JPH0614328A - Waveform equalizing system - Google Patents

Abstract

PURPOSE:To compensate the transmission distortion of transmitted luminance signal and chrominance signal in each transmission line. CONSTITUTION:This system is provided with a reference signal inserting means D connected to the prestage of a transmitting side processing system A so as to insert a composite reference signal into a prescribed position of a composite video signal at the time of inputting the composite video signal or insert luminance and chromi-nance reference signals separated from the composite reference signal into respective prescribed positions in the luminance signal and the chrominance signal at the time of inputting the luminance and chrominance signals and a waveform equalizing means E including a detection means for fetching the luminance and chrominance reference signals transmitted through a receiving side processing system C and detecting distortion received at the time of transmitting these signals and two filtering means for canceling a transmission distortion component detected from the luminance and chrominance signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveform equalization system for compensating for transmission distortion in equipment for transmitting video signals.

[0002]

2. Description of the Related Art FIG. 12 is a conceptual diagram of a transmission system for transmitting a video signal.

As shown in the figure, a video signal is transmitted via a transmission side processing system A, a transmission line B, and a reception side processing system C, respectively. And as this transmission system, for example, VT
Various types such as R, package media, and CATV can be considered.

Specifically, in the VTR, the transmission side processing system A corresponds to the recording signal processing means, the transmission line B corresponds to the tape head system, the reception side processing system C corresponds to the reproduction signal processing means, and the video disk and In package media such as video software, the transmission side processing system A corresponds to the recording signal processing means at the time of creating the master / master tape, the transmission line B corresponds to various package media, and the reception side processing system C corresponds to the reproduction signal processing means.
In the CATV, the transmission side processing system A is transmission signal processing means, the transmission line B is wired (optical cable, etc.), and the reception side processing system C is
Correspond to the received signal processing means in the repeater or terminal, respectively.

In these various transmission systems, various waveform equalization systems have been proposed for compensating the respective transmission characteristics, that is, for compensating the distortion generated in the transmission system.

As an example of a waveform equalization system for compensating for distortion generated in this transmission system, the following (1) and (2) used in a VTR or the like will be described as an example.

That is, as the compensating means (1), at the time of recording, a video signal in which a reference signal having a frequency near the upper limit of the reproduction frequency bandwidth is inserted in a part of the vertical blanking period of the video signal is recorded and reproduced. At this time, a magnetic recording / reproducing apparatus that supplies the reference signal extracted from the reproduction signal to the frequency characteristic varying means and reproduces it so that the reproduction level of the reference signal becomes constant, aligns the frequency characteristics during reproduction, and compensates for the deterioration of the transmission characteristic. It is known (for example, JP-A-61-41284).

The compensating means (2) records a video signal in which a ramp signal is inserted in a part of the blanking period of the video signal at the time of recording, and at the time of reproduction, a reproduction ramp signal extracted from the reproduction signal and a reference. There is known a recording / reproducing method of a video signal for compensating the deterioration of the transmission characteristic by detecting the correction amount by comparing the level with the ramp signal and correcting the level of the reproduced video signal based on the detected correction amount (for example, Japanese Patent Laid-Open Publication No. Sho. 61-46681).

[0009]

However, the above-mentioned conventional compensating means (1) and (2) have the following problems.

That is, in the compensating means (1), since the target of compensation is only the frequency characteristic, other deteriorations (ringing, smear, etc.) cannot be compensated, and the reference signal is reproduced at a single frequency. Appropriate compensation can be performed only when the frequency characteristic of the signal is linear, and it may be inconvenient to use it for other than this.

Further, in the compensating means (2), since the objects of compensation are only the linearity and the gain, compensation for other deteriorations is still impossible, resulting in non-linear distortion (distortion due to white / dark clip, emphasis, etc.). I couldn't handle it.

[0012]

In order to solve the above problems, the present invention provides a waveform equalization system having the following configuration.

A waveform equalization system for compensating the transmission distortion of a transmitted video signal, which is provided in the preceding stage of a transmission side processing system, and when a composite video signal is input, a composite reference signal is used as the composite video signal. When the luminance signal and the color signal are input at the specific position of,
Luminance transmitted through the receiving side processing system and a reference signal inserting means for inserting a luminance reference signal and a color reference signal obtained by separating the composite reference signal into specific positions in the luminance signal and the color signal, respectively. The reproduction luminance reference signal is captured from the signal, the reproduction color reference signal is captured from the color signal transmitted through the receiving side processing system, and the distortions received by the reproduction luminance reference signal and the reproduction color reference signal are transmitted. A waveform or the like characterized by having a detecting means for detecting and a waveform equalizing means provided with a filter means for canceling each transmission distortion component of the luminance signal transmission system and the color signal transmission system detected by the detection means. System.

[0014]

1 is a block diagram of an embodiment of a waveform equalization system according to the present invention.

As shown in FIG. 1, the waveform equalization system 1
12 has the same configuration as that of the transmission system shown in FIG. 12, in which the reference signal inserting means D is provided in the preceding stage of the transmitting side processing system A and the waveform equalizing means E is provided in the subsequent stage of the receiving side processing system C. Further, the waveform equalizing means E includes a detecting means 10 and digital filter means 13 and 20, as will be described later.

The waveform equalization system 1 is provided in the preceding stage of the transmission side processing system A, and when a composite video signal is input, a composite reference signal is inserted at a specific position of the composite video signal to obtain a luminance signal. And a color signal is input, reference signal inserting means D for inserting a luminance reference signal and a color reference signal obtained by separating the composite reference signal into specific positions in the luminance signal and the color signal, respectively. , A reproduction luminance reference signal from the luminance signal transmitted via the reception side processing system C, and a reproduction color reference signal from the color signal transmitted via the reception side processing system C to obtain the reproduction luminance reference signal And detecting means 10 for detecting the distortion received by the reproduced color reference signal during transmission, respectively.
Filtering means 1 for canceling each transmission distortion component of the luminance signal transmission system and the chrominance signal transmission system detected by the detection means 10.
By having the waveform equalizing means E provided with 3 and 20, the transmitted luminance signal and chrominance signal are reproduced to reduce the transmission distortion between the transmission side processing system A → transmission path B → reception side processing system C. By detecting and processing the reproduced luminance signal and reproduced chrominance signal so as to cancel the distortions respectively, optimum and all distortions can be independently corrected according to each transmission system, and the transmission characteristics of both transmission systems are compensated. To do.

The VTR will be described below as an example.

FIG. 2 is a block diagram of an embodiment of the reference signal inserting means D which is a main part of the waveform equalization system according to the present invention, FIG. 3 is a waveform diagram of the reference signal, and FIG. signal,
FIG. 4B is a color reference signal, FIG. 4C is a composite reference signal, and FIGS. 4 and 10 are waveform diagrams of a recording luminance signal and a recording color signal in which a luminance reference signal and a color reference signal are inserted, respectively. 5A to 5D are waveforms of the recording luminance signal and the recording color signal in the first to fourth fields, and FIG. 5 is provided in the receiving side processing system C of the waveform equalizing system according to the present invention. FIG. 6 is a configuration diagram of the comb filter, and FIG. 6 is an input / output signal waveform diagram of the comb filter.
(C) and (E) are input reproduction luminance signal waveforms of the comb filter, respectively, (B), (D), and (F) are output reproduction luminance reference signal waveforms of the comb filter, respectively, and FIGS. FIGS. 9A and 9B are configuration diagrams of the first and second embodiments of the waveform equalizing means E, which are essential parts of the waveform equalization system according to the present invention, and FIG. 9 is an explanatory diagram for compensating for deterioration of transmission characteristics. ) Is a signal waveform at the time of recording, (B) is a reproduced signal waveform, (C) is a main signal path waveform, (D) is an antiphase pseudo-distortion waveform, and (E) is a main signal. FIG. 11 is a block diagram for explaining the timing circuit, which is the summed waveform of the path waveform and the anti-phase pseudo distortion.

In FIG. 2, 2 is a reference signal insertion circuit, 2A is a sync separation circuit, 2B is a timing generation circuit,
2C is a clock generation circuit, 2D is a reference signal storage circuit (R
OM), 2E is a D / A converter (DAC), 2F is a low-pass filter circuit (LPF), a, b, d, e, g, h, j,
k, m and n are fixed contacts, c, f, i, l and o are movable contacts, SW1, SW2, SW3, SW4 and SW5 are changeover switches, and 3 is a Y / C separation circuit.

The reference signal insertion circuit 2 shown in FIG. 2 is a recording signal processing means (luminance (Y) signal recording processing means and color (C)) of a VTR corresponding to the transmission side processing system A of the waveform equalization system 1.
Signal recording processing means).

Although not described in detail here, the above-mentioned V
The luminance signal recording processing means of the TR sequentially reaches the video head through the AGC circuit, the clamp circuit, the pre-emphasis circuit, the clipping circuit, the FM modulator, the high-pass filter, the recording amplifier, the rotary transformer, etc. The signal recording processing means sequentially goes to the recording amplifier of the luminance signal recording processing means through the ACC circuit, the frequency converter, the low-pass filter, the killer circuit and the like.

By the way, as an input signal of the VTR, the S terminal (Separate terminal, S input) for the separate input of the luminance signal (Y) and the color signal (C), the luminance signal input terminal and the color signal input terminal are integrated. And a composite video signal input terminal (composite video input) for composite signal input.

The S terminals are respectively connected to one input terminals h and k of changeover switches SW3 and SW4 provided on the output side of the reference signal inserting circuit 2, and the composite video signal input terminals are changeover switches SW5 and SW5. / C separation circuit 3
And the other input terminals g and j of the signal changeover switches SW3 and SW4, respectively.

The changeover switches SW1 and SW2 are switches interlocked with each other according to an input signal. When only a composite video signal is inputted, the changeover switches SW1 and SW2 are switched downward in the figure (the movable contact c of the changeover switch SW1 is a fixed contact b). , The movable contact f of the changeover switch SW2 is switched to the fixed contact e), and the combination of the luminance signal and the color signal (hereinafter referred to as the S signal) is simultaneously input, or only the S signal is input. Is switched upward in the figure (the movable contact c of the changeover switch SW1 is changed to the fixed contact a and the movable contact f of the changeover switch SW2 is changed to the fixed contact d).

The output signal of the change-over switch SW1 output via the movable contact c is a luminance signal or a composite video signal, which is taken out by the sync separation circuit 2A as a horizontal sync signal or a vertical sync signal. It is guided to the timing generation circuit 2B.

The timing generation circuit 2B generates a burst gate pulse for extracting a color burst signal from the color signal or the composite video signal, supplies this signal to the clock generation circuit 2C, and at the same time, outputs the composite reference signal to the reference signal storage circuit. An address signal for reading from 2D is generated, and a switching signal for the reference signal insertion switch SW5 is generated.

The clock generation circuit 2C extracts a color burst signal from the color signal or composite video signal supplied via SW2 based on this burst gate pulse, and is an integer multiple of the burst frequency phase-locked with this (for example, 4 A clock of double frequency. This serves as a master clock for operating the entire reference signal insertion circuit 2.

The reference signal storage circuit 2D stores the data of the composite reference signal shown in FIG. 2C and outputs the data according to the address signal from the timing generation circuit 2B. The data of the composite reference signal is D / A. It is converted into an analog signal by the converter 2E.

As will be described later, the timing of reading the data of the composite reference signal from the reference signal storage circuit 2D is different when the composite video signal is input and when the S signal is input.

The operation of changing over the changeover switches SW3, SW4, and SW5 is different when the composite video signal is input and when the S signal is input, and therefore, description will be given separately for each case.

When a composite video signal is input, the changeover switch SW5 functions as a switch for inserting a composite reference signal, and normally (a period other than the reference signal insertion period) is switched upward (the movable contact o of the changeover switch SW5 is fixed). Although the composite video signal is passed through as it is (switched to the contact m), when it comes to the reference signal insertion section, it is switched downward according to the switch signal from the timing generation circuit 2B (the movable contact o of the switch SW5 is switched to the fixed contact n). The composite reference signal is selectively output.

The composite video signal in which the composite reference signal is inserted is separated into a luminance signal and a chrominance signal in the Y / C separation circuit 3 and sent to the fixed contact g of the changeover switch SW3 and the fixed contact j of SW4, respectively.

At this time, the changeover switches SW3 and SW4 are switched downward (the movable contact i of the changeover switch SW3 is changed to the fixed contact g and the movable contact l of the changeover switch SW4 is changed to the fixed contact j), and the luminance signal and The color signal is sent to each transmission system.

When the S signal is input, the S signal is preferentially processed even when the composite video signal is input at the same time.

The changeover switch SW5 is always switched downward (the movable contact o of the changeover switch SW5 has a fixed contact n).
The composite reference signal is selected, and the Y / C separation circuit 3 separates the composite reference signal into a luminance reference signal and a color reference signal.

The changeover switches SW3 and SW4 are normally switched upward in the figure (the movable contact i of the changeover switch SW3 is changed to the fixed contact h and the movable contact l of the changeover switch SW4 is changed to the fixed contact k), and the S signal is kept as it is. Through,
When it comes to the reference signal insertion section, it is switched downward according to the switching signal from the timing generating circuit 2B (the movable contact i of the switching switch SW3 is the fixed contact g, the switching switch SW is
The movable contact 1 of 4 is switched to the fixed contact j), and the luminance reference signal and the color reference signal are selected.

The switching timings of the changeover switches SW3 and SW4 are the same.

Thus, the composite reference signal is Y
After passing through the / C separation circuit 3, the luminance reference signal and the color reference signal are sent to the respective transmission systems in a separated state, so that the Y / C separation circuit 3 is different from that when the composite video signal is input.
It is necessary to read out faster by the delay time in. The address signal supplied from the timing generation circuit 2B to the reference signal storage circuit 2D is generated in consideration of this point.

As described above, according to this method, it is not necessary to have the reference signal generating circuit for the luminance reference signal and the reference signal generating circuit for the color reference signal exclusively, and only one system of the composite video reference signal generating circuit is required, so that the circuit scale and the cost are reduced. Is excellent in terms of.

Here, the above-mentioned brightness reference signal will be described.

The luminance reference signal is used for the purpose of compensating for transmission distortion (deterioration of transmission characteristics) in the luminance signal transmission system (luminance signal recording processing means → tape / head system → luminance signal reproduction processing means), and serves as a luminance signal. It is a signal that has characteristics and can reliably detect this transmission distortion.

FIG. 3A shows an example of a luminance reference signal waveform. This luminance reference signal is a bar waveform having a rising characteristic of SINX / X, and is displayed in a specific line (for example, in a vertical blanking period). 12th line).

The characteristics of the SINX / X used here have, for example, flat frequency characteristics up to the system transmission band in order to compensate the entire band of the waveform equalization system (for example, S-VHS
If the frequency is higher than that, the characteristic is a characteristic obtained by applying an appropriate window function that attenuates with an appropriate curve (for example, squared cosine characteristic).

The above-mentioned color reference signal will be described.

The color reference signal is used for the purpose of compensating for the transmission distortion in the color signal transmission system (color signal recording processing means → tape / head system → color signal reproduction processing means), and has a characteristic as a color signal and This is a signal that can reliably detect transmission distortion.

FIG. 3B shows an example of a color reference signal in a color signal transmission system which is quadrature two-phase modulated. This color reference signal is, for example, the lower limit frequency of the color signal band (for example, 3.
It is a sine sweep signal whose frequency linearly increases from 08 MHz) to an upper limit frequency (4.08 MHz, for example), and is a signal whose phase is inverted at the position of the central color subcarrier frequency (3.58 MHz, for example).

FIG. 3C shows an example of the composite reference signal waveform.

In FIGS. 3A to 3C, the timing positional relationship between the luminance reference signal and the color reference signal is 50% of the rising time of the bar waveform of the luminance reference signal and the time when the phase of the color reference signal is inverted. Are set so that they coincide with each other, and what is mixed at this timing is the composite reference signal.

The reason is that the timing deviation between the luminance reference signal and the color reference signal can be easily detected from the reproduced luminance reference signal and the reproduced color reference signal to be reproduced.

FIG. 4 shows the waveforms of the recording luminance signal and the recording color signal in which the luminance reference signal and the color reference signal are inserted.
It shows the timing positions of the luminance reference signal and the color reference signal in the TSC video signal.

As shown in (A) to (D) of FIG.
The luminance reference signal shown in (A) is the 12th line (12H) of each luminance signal in the first to fourth fields.
The video signal periods of the 11th line and the 13th line which are adjacent to the video signal period in which the luminance reference signal is inserted are in the blanking state.

The color reference signal shown in FIG. 3B is inserted in the video signal period of the twelfth line of each color signal in the first to fourth fields, similarly to the above-mentioned insertion timing of the luminance reference signal. 11th line and 13th line adjacent to the video signal period in which the color reference signal is inserted.
Each video signal period of the line is blanked, but in order to match the color sequence, the color reference signal of the odd field (first and third fields) and the color reference signal of the even field (second and fourth fields) The signals are recorded so that their hues are opposite to each other (become opposite phases).

In this state, the first field is "C +" and the second field is "C" in FIGS.
The symbol "-", the third field is indicated by "C-", and the fourth field is indicated by "C +", and the relationship with the color burst phase is cycled every four fields (frames A and B).

The reception side processing system C of the waveform equalization system 1 may be equipped with the line correlation type comb filter 4 shown in FIG. 5 as a noise canceller.

For example, when the two-line correlation type comb filter 4 shown in FIG. 5 is installed in the receiving side processing system C,
When a luminance signal in which one line before and after the luminance reference signal shown in FIG. 6 (A) is not blanked is input to this filter 4, the signal shown in FIG. 6 (B) is output and the luminance reference signal is inserted. In the twelfth line, a signal obtained by adding the half amplitude of the luminance reference signal and the half amplitude of the preceding one line (or the succeeding one line) having no line correlation appears here.

As described above, since the reproduction luminance reference signal is disturbed by the unspecified signal of the preceding one line (or the following one line) and unspecified distortion unrelated to the transmission characteristic is generated, characteristic compensation is performed. I can't do well.

When a luminance signal in which only one line before the luminance reference signal shown in FIG. 6C is blanked is input to the filter 4, the signal shown in FIG. The twelfth line in which the reference signal is inserted is a signal obtained by adding 1/2 amplitude of the luminance reference signal and 1/2 amplitude of the preceding 1 line (or the following 1 line) having no line correlation. It may appear.

As described above, the reproduction luminance reference signal is disturbed by the unspecified rear-line signal, and unspecified distortion unrelated to the transmission characteristics occurs, so that characteristic compensation cannot be performed well.

In order to solve the above-mentioned problem, when a luminance signal in which one line before and after the luminance reference signal shown in FIG. 6E is blanked is input to this filter 4, the luminance signal shown in FIG. The signal shown is output, and only the reproduced luminance reference signal having an amplitude half that of the luminance reference signal appears therein, so that the characteristic can be compensated for without the unspecified interference.

The comb filter 4 is composed of a delay circuit (1H delay) 5, an adder circuit 6 and an attenuator circuit (1/2) 7.

Further, when a 3-line correlation type comb filter is used as the noise canceller, similarly, FIG.
When the luminance signals shown in (A) and (C) are input, the signals shown in (B) and (D) of the figure are output, and the reproduction luminance reference signal is disturbed and unspecified unrelated to the transmission characteristics. However, if the luminance signal shown in (E) is input, the signal shown in (F) is output and the reproduced luminance reference signal is not disturbed. It goes without saying that good compensation can be achieved.

Here, the operation of the noise canceller may be stopped at least during the luminance reference signal insertion period (the 12th line), and by doing so, interference by the noise canceller does not occur, and FIG. As shown, the amplitude is never halved.

Since the color signal system may use a noise canceller such as CNR (color noise reduction), in such a case, a period corresponding to the color reference signal insertion period (luminance reference signal insertion period (12th line)). ) It is necessary to stop this operation, for example, by cutting the loop for a period.

Although the above description of FIGS. 6A to 6F is for the luminance signal, the color signal is the same as the luminance signal shown in FIG. 6E although not described in detail here. When a color signal in which one line before and after the color reference signal is blanked is input to the filter 4,
Similar to the signal shown in FIG. 7F, only the reproduced color reference signal having an amplitude half that of the color reference signal appears here, so that this signal can be subjected to characteristic compensation without unspecified interference. It goes without saying that you can do it.

By the way, the luminance signal in which the luminance reference signal is inserted by the reference signal inserting means D (reference signal inserting circuit 2) shown in FIG. 2 and the color signal in which the color reference signal is inserted are VT.
At R, each is supplied to a transmitting side processing system A which is a recording signal processing means and is subjected to each recording process to be a recording luminance signal and a recording color signal, and then recorded through a tape head system which is a transmission line B, Then, during reproduction, VT from this transmission line B
In R, each is supplied to a receiving side processing system C which is a reproduction signal processing means, and through each reproduction process, the above-described recording luminance signal and recording color signal are reproduced to obtain a reproduction luminance signal and a reproduction color signal, which will be described later. The waveform equalizer E reproduces and outputs the reproduction luminance signal and the reproduction color signal obtained by waveform equalization based on the reproduction luminance reference signal and the reproduction color reference signal extracted from the reproduction luminance signal and the reproduction color signal.

The above-mentioned waveform equalizing means E is the receiving side processing system C.
Detection means 10 for taking in a reproduction reference signal based on the reference signal from the video signal transmitted via the reference signal and detecting the distortion received by the reference signal during transmission, and filter means 13 for canceling the transmission distortion component detected from the transmitted video signal. , 20 and.

7 and 8 are configuration diagrams of the first and second embodiments of the waveform equalizing means, which is a main part of the waveform equalizing system according to the present invention.

7 and 8, 8A and 24A are reproduction luminance signal transmission characteristic compensation circuits, 8B and 24B are reproduction color signal transmission characteristic compensation circuits, 9 is a clock generation circuit, and 10 is CP.
U (detection means), 11 and 18 are A / D converters (AD
C), 12, 19, 26 and 28 are delay circuits (DLY),
13, 20 are transversal filters (digital filter means), 14, 21, 25, 27 are adders, 15
Is a variable delay circuit (VDL), 16 and 22 are D / A converters (DAC), 17 and 23 are low-pass (LPF) filters, C
Is a receiving side processing system, and E is a waveform equalizing means. The reproduction luminance signal transmission characteristic compensation circuit 8A is a feedback control system including a delay circuit 12, a transversal filter 13, and an adder 14, and the reproduction color signal transmission characteristic compensation circuit 8B is a delay circuit 19, a transversal filter 20, and an adder 21.
The reproduction luminance signal transmission characteristic compensating circuit 24A is composed of a transversal filter 13, an adder 25, and a delay circuit 26, and a reproduction color signal transmission characteristic compensating circuit 24B. Is a transversal filter 20 and an adder 2
7, a feedforward control system including a delay circuit 28.

The waveform equalizing means E shown in FIGS. 7 and 8 corresponds to the receiving side processing system C of the waveform equalizing system 1 and is the reproduction signal processing means (luminance (Y) signal reproduction processing means and color (C)) of the VTR. Signal reproduction processing means).

Although not described in detail here, the above V
The brightness signal reproduction processing means of the TR includes a preamplifier circuit, a channel switcher, a high-pass filter circuit, a dropout compensation circuit (DO) from a rotary transformer through a video head.
C), a limiter circuit, an FM demodulator, a de-emphasis circuit, a low-pass filter circuit, etc. in sequence, and the above-mentioned color signal reproduction processing means passes through a preamplifier circuit of the luminance signal reproduction processing means and then a low-pass filter, The ACC circuit, the frequency converter, the bandpass filter circuit, the killer switch, etc. are sequentially provided.

Now, as shown in FIG. 7, the reproduction luminance signal (reproduction Y) supplied from the above-mentioned luminance signal reproduction processing means.
Is supplied to the clock generation circuit 9 and the A / D converter 11, respectively, and the reproduction color signal (reproduction C) supplied from the color signal reproduction processing means is supplied to the clock generation circuit 9 and the A / D converter 11.
They are supplied to the D converters 18, respectively.

The clock generation circuit 9 generates and outputs a clock similar to the clock generated from the clock generation circuit 2C in the reference signal insertion circuit 2 shown in FIG. That is, the clock generation circuit 9 generates a burst gate pulse from the reproduced color signal based on the horizontal and vertical sync signals extracted from the reproduced luminance signal, extracts a color burst signal from the reproduced color signal using the burst gate pulse, and bursts the burst signal. A clock having an integral multiple (for example, four times the frequency) of the color burst frequency synchronized with the gate pulse is generated and output.

The clock output from the clock generation circuit 9 is a reproduction luminance signal transmission characteristic compensation circuit 8A, a reproduction color signal transmission characteristic compensation circuit 8B, A / D converters 11 and 18, a variable delay circuit 15, and a D / A converter. It is supplied to 16 and 22, respectively.

Here, the waveform equalization of the waveform equalizer E shown in FIG. 7 will be described with reference to FIG.

For convenience of explanation, the waveform equalization will be described only for the reproduction luminance signal, but it goes without saying that the waveform equalization can be performed for the reproduction color signal as well.

Now, the recording luminance signal output from the above-mentioned reference signal inserting circuit 2 and having the luminance reference signal inserted therein (see FIG. 9).
The waveform aa) shown in FIG. 9A is recorded on the tape after being converted into a recording luminance signal through each recording process in the recording signal processing means.
It is recorded via the head system.

At the time of reproduction, the reproduction luminance signal (waveform bb shown in FIG. 7B) reproduced through each reproduction process in the reproduction signal processing means is the A / D converter 11 of the waveform equalizing means E.
Is supplied as an A / D-converted digital data signal to the delay circuit 12 and the transversal filter 13 each including a multistage shift register.

From the delay circuit 12, a delay signal (see FIG.
A digital signal corresponding to the waveform cc) is output, and the transversal filter 13 outputs a compensation signal (a digital signal corresponding to the waveform dd shown in FIG. 3D).

This transversal filter 13 is a CP
Under the control of U10, the above-mentioned compensation signal having a phase opposite to that of the signal component is output so as to cancel the signal component according to the deterioration of the transmission characteristics in the delay signal.

In this way, the adder 14 adds the compensation signal from the transversal filter 13 to the delay signal from the delay circuit 12 to cancel the signal component corresponding to the deterioration of the transmission characteristic. A digital signal corresponding to the waveform ee shown in FIG. 7E is output.

The reason why the delay circuit 12 is composed of a shift register is that the adder 14 matches the timing with the compensating signal from the transversal filter 13, and it depends on the number of taps of the transversal filter 13. This is to realize a delay amount that is uniquely determined.

The reproduction luminance signal including the reproduction luminance reference signal output from the adder 14 and having the deterioration of the transmission characteristic compensated is supplied to the variable delay unit 15.

The variable delay unit 15 is composed of, for example, a variable length shift register in which the delay amount is variable according to the control signal from the CPU 10.

The variable delay unit 15 roughly adjusts the timing of the reproduction luminance signal supplied here to the timing of the reproduction color signal in units of half clocks, and then the reproduction luminance signal is output in units of half clocks. One of them is supplied to the D / A converter 16, where it is D / A converted, and then becomes a final reproduction luminance signal via the low-pass filter circuit 17,
The other output is directly supplied to the CPU 10.

As described above, the variable delay unit 15 can adjust the timing of the reproduction luminance signal in half clock units of the reproduction color signal in half clock units of the reproduction color signal.
Further, even for minute timing adjustment within a half clock (a minute delay amount), by using the sampling frequency converter 29 described later, a phase corresponding to the delay amount with respect to the target clock phase is converted at the time of sampling frequency conversion here. By giving it as an offset, it is possible to adjust the timing within a half clock at the same time as the frequency conversion.

Here, although the reproduction luminance reference signal is inserted in the reproduction luminance signal output from the low-pass filter circuit 17, since this insertion position is within the vertical blanking period of the reproduction luminance signal, it remains as it is. By supplying the reproduction luminance signal together with the reproduction color signal from the low-pass filter circuit 23 to the reproducing means such as a TV receiver (not shown), a good reproduced image can be obtained, but this reproduction luminance reference signal is extracted. In order to obtain the reproduction luminance signal, the variable delay device 15 and the D / A converter 16 in FIG.
It suffices to insert a reference signal extracting circuit complementary to the reference signal inserting circuit 2 shown in FIG.

The reproduction luminance signal output from the variable delay unit 15 to the CPU 10 and including the reproduction luminance reference signal is converted from the reproduction luminance signal by the CPU 10 in accordance with the timings of the luminance signal and the color signal shown in FIGS. The transversal filter 13 outputs a control signal corresponding to the difference obtained by comparing the extracted reproduction luminance reference signal waveform (the above-mentioned waveform bb) and the recording luminance signal waveform (the above-mentioned waveform aa) with the same normal waveform.
And the coefficient of the transversal filter 13 is changed so that this difference does not occur.

The CPU 10 takes in the reproduction luminance reference signal reproduced in each field, and gradually updates the coefficient of the transversal filter 13 so that the reproduction luminance reference signal waveform becomes the same as the recording luminance reference signal waveform. Go.

The reproduced waveform used for the calculation at this time is S / N.
In order to improve the performance, several fields period synchronous addition is performed and used.

Although the above description has been made with respect to compensating for the deterioration of the transmission characteristics in the luminance signal transmission system, the deterioration of the transmission characteristics can be similarly compensated for in the chrominance signal transmission system as well. It is possible to compensate for the deterioration of transmission in both the luminance signal and chrominance signal transmission systems.

That is, in the color signal transmission system, the recording color signal output from the above-mentioned reference signal inserting circuit 2 and into which the color reference signal is inserted is converted into a recording color signal through each recording process in the recording signal processing means. , Is recorded via a tape head system.

At the time of reproduction, the reproduction color signal reproduced through each reproduction process in the reproduction signal processing means is multistaged as a digital data signal A / D converted by the A / D converter 18 of the waveform equalizing means E. The signals are supplied to the delay circuit 19 including a shift register and the transversal filter 20, respectively.

A delay signal is output from the delay circuit 19,
A compensation signal is output from the transversal filter 20. This transversal filter 20 is a CPU
By the control of 10, the above-mentioned compensation signal having a phase opposite to that of the signal component is output so as to cancel the signal component corresponding to the deterioration of the transmission characteristic in the delay signal.

In this way, the adder 21 adds the compensation signal from the transversal filter 20 to the delay signal from the delay circuit 19 to obtain a delayed signal from which a signal component corresponding to the deterioration of the transmission characteristic is canceled. Is output.

Here, the reason why the delay circuit 19 is composed of a shift register is that the adder 21 matches the timing with the compensation signal from the transversal filter 20, and it depends on the number of taps of the transversal filter 20. This is to realize a delay amount that is uniquely determined.

One of the reproduced color signals output from the adder 21 and including the reproduced color reference signal in which the deterioration of the transmission characteristic is compensated,
After being supplied to the D / A converter 22 and D / A converted, it becomes a final reproduced color signal via the low-pass filter circuit 23, and the other output is directly supplied to the CPU 10.

Here, although the reproduction color reference signal is inserted in the reproduction color signal output from the low-pass filter circuit 23, since this insertion position is within the vertical blanking period of the reproduction color signal, it is practically used. Although there is no upper limit, in order to obtain a reproduction color signal obtained by extracting the reproduction color reference signal, in FIG.
Between the adder 21 and the D / A converter 22 (adder 21 and C
It suffices to insert a reference signal extracting circuit complementary to the reference signal inserting circuit 2 shown in FIG.

The CPU 10 takes in the reproduced color reference signal reproduced in each field, and gradually updates the coefficient of the transversal filter 13 so that the reproduced color reference signal waveform becomes the same as the color reference signal waveform at the time of recording. Go.

The reproduced waveform used for the calculation at this time is S / N.
In order to improve the performance, several fields period synchronous addition is performed and used.

By the way, as a basic algorithm for updating the coefficients of the above-mentioned transversal filters 13 and 20, the steepest descent method is used, and a tap updating formula such as the following formula (1) is used.

Cn ^* = Cn−αen Equation (1) where Cn current nth tap coefficient Cn ^* updated current nth tap coefficient en nth error signal α correction coefficient (<1) The update is performed every several fields within the vertical blanking period, and is not performed in the effective scanning period of the luminance signal and the color signal, the color burst signal period, and the horizontal / vertical synchronization signal period.

The above-mentioned waveform bb shown in FIG. 9B is obtained by reproducing the waveform aa shown in FIG. 9A,
Ringing is caused by distortion of transmission characteristics.

The waveform dd in FIG. 7D is a filter output whose coefficient is controlled by the CPU 10, and is a waveform b
It has an anti-phase component of distortion contained in b.

The above luminance reference signal and color reference signal are
The 11th to 13th lines are used when the blanking lines of the 11th and 13th lines are included in the 12th line in the vertical blanking period of the luminance signal and the chrominance signal, but not limited to this. 10th line to 13th
Any period may be set during the period of the line and the 17th to 20th lines.

However, the 14th line to the 16th line, the 2nd line
Since one line is used for teletext, this line may be used if there is no need to coexist with it.

Further, although the above-mentioned luminance reference signal and color reference signal are described as a one-field / four-field sequence, a two-line / field four-field sequence as shown in FIGS. good.

In this case, a total of 4 lines including 2 lines before and after blanking are applied, the same signal is recorded on the 11th line and the 12th line of each field, and the color reference signal is on the same line. Is inserted at the same timing as the luminance signal.

The color reference signal is set so that the hue is inverted between consecutive lines and the same line in the even field next to the odd field.

This is because when the transmission system has an arithmetic circuit (Y / C separation circuit, noise reduction, etc.) that utilizes the correlation between fields or frames, the color reference signal is mistaken for the luminance reference signal in this arithmetic circuit. This is to prevent detection and malfunction.

FIG. 10 is a waveform diagram of the recording luminance signal and the recording color signal in which the luminance reference signal and the color reference signal are inserted.
It shows timing positions of a luminance reference signal and a color reference signal in an NTSC video signal.

As shown in (A) to (D) of FIG.
The luminance reference signal shown in (A) is the 11th and 12th lines (1) of each luminance signal in the first to fourth fields.
1H, 12H) are inserted in each video signal period,
The video signal periods of the 10th line and the 13th line (10H, 13H) are blanked.

Further, the color reference signal shown in FIG. 3B is similar to the above-described luminance reference signal insertion timing, and the eleventh and eleventh color signals in the first to fourth fields are used.
It is inserted in the video signal period of 12 lines, respectively.
The video signal periods of the 0th line and the 13th line are blanked, but in order to match the color sequence, the color reference signal of the odd field (first and third fields) and the even reference field (second and fourth fields) are used. The recording is performed so that the hue is opposite to (reverse to) the color reference signal of the (field).

In this state, the color reference signals of the 11th and 12th lines in the first field are "C +" and "C-", respectively, and the second field is "C" in FIGS.
-"," C + ", and the third field is" C- "," C ", respectively.
The "+" and the fourth field are indicated by the symbols "C +" and "C-", respectively, and the relationship with the color burst phase is cycled every four fields (frames A and B).

Further, since the color reference signal is not a signal to be viewed on the screen, it is not always necessary to satisfy the color sequence if there is no arithmetic circuit utilizing field / frame correlation in the transmission system.

For example, there is no problem even if the same signal is inserted in each field.

The reproduction luminance signal transmission characteristic compensating circuits 8A and 8B shown in FIG. 7 are feedback control systems, respectively, and the above description is also provided along with this, but instead, it is shown in FIG. Playback luminance signal transmission characteristic compensation circuit 2
A feedforward control system such as 4A and 24B may be used. Further, both may be combined.

In the waveform equalizing means E shown in FIG. 8, the reproduction luminance signal transmission characteristic compensation circuits 8A and 8B are removed from the waveform equalization means E shown in FIG. , 24B, and the other components are the same as those shown in FIG. 7, the same components are designated by the same reference numerals,
Although the description is omitted, it goes without saying that the waveform equalization of the reproduction luminance signal and the reproduction color signal can be performed in the same manner as the waveform equalization means E shown in FIG.

In this case, since the reproduction signal transmission characteristic compensating circuits 8A and 8B are feedback control systems, the tap updating equation using the above equation (1) cannot be used, but it is performed under the control of the CPU 10. The updating of the taps for the transversal filters 13 and 20 is performed every several fields within the vertical blanking period, and is not performed during the effective scanning period of the luminance signal and the chrominance signal, the color burst signal period, and the horizontal and vertical synchronization signal period. Of course,

By the way, the clock generating circuit 9 shown in FIGS. 7 and 8 generates and outputs a clock of an integral multiple (for example, four times the frequency) of the color burst frequency synchronized with the burst gate pulse. Instead of the clock, it is synchronized with the horizontal synchronizing signal included in the reproduction luminance signal and is an integral multiple thereof (for example, 910 for an NTSC video signal).
A clock having a double frequency) may be used, or a clock synchronized with a color burst signal included in the reproduced color signal and having an integral multiple thereof (for example, a color subcarrier frequency of four times for an NTSC video signal). You may use.

Now, in a domestic VTR without a TBC (time base collector), since the phase relationship between the color subcarrier frequency and the frequency of the horizontal / vertical synchronizing signal is not always constant and fluctuates along the time axis, the reproduced color is changed. If the clock generated from the signal (or the reproduction luminance signal) is used commonly for both the color signal and luminance signal transmission systems, there is a problem that an error occurs on the time axis between both signal transmission systems.

In order to solve this, the timing circuit 43 having the configuration shown in FIG.
5 and the D / A converter 16 are inserted and connected, and the variable delay unit 15
After roughly adjusting the timing of the reproduction luminance reference signal and the reproduction color reference signal in half clock units from the clock generation circuit 9, the CPU 10 controls the phases to slightly differ (for example, 1 to 2 nsec each). From the clocks, the clock closest to this timing shift is selected by the multiplexer 39, and the flip-flop circuit 42 is selected.
A method is used in which the reproduction luminance signal output from the variable delay unit 15 is D / A-converted by the D / A converter 16 in synchronization with this clock to enable timing adjustment within half a clock.

Clocks having different phases have delay times of 1 to 2
Buffer circuits 40a, 40b, 40c, ...
40n are cascade-connected by an appropriate number of stages, and each output side of the buffer circuits 40a, 40b, 40c, ..., 40n is connected to the parallel input side of the multiplexer 39.

Thus, in the timing circuit 43, C
By changing the clock selection signal supplied from the PU 10 to the multiplexer 39, the multiplexer 3
The phase of the clock output from 9 is varied, and this variable control is updated every few fields until the timings of the reproduction luminance signal and the reproduction color signal match (converge).

The timing circuit 43 having the configuration shown in FIG. 11 is inserted and connected between the variable delay device 15 and the D / A converter 16 of the luminance signal transmission system, and the reproduction luminance signal is reproduced at the timing of the reproduction color signal. Although not described in detail here, the timing circuit 43 is used for the reproduction color signal transmission characteristic compensation circuit 8B (24B) of the color signal transmission system and the D / A.
It is needless to say that the timing of the reproduction color signal can be matched with the timing of the reproduction luminance signal by inserting and connecting with the converter 22 in the same manner as described above.

The above description is for the case where the system of the present invention is applied to a VTR having a well-known structure, but other recording / reproducing means such as a magnetic disk or an optical disk can also be applied.

Further, even when there is no recording process on the user side such as a package medium such as a video disc or video software, the same effect can be obtained by recording with the reference signal at the time of creating the package medium.

Not only in the case of recording / reproducing, but also in a system that generally transmits a signal, for example, CATV or wireless communication, the reference side is transmitted including the reference signal on the transmission side, and the waveform is equalized on the reception side. By doing so, the same effect can be obtained.

It is also possible to continuously insert the above-mentioned reference signal for at least two horizontal synchronization periods of the video signal. In this case, interference is caused by the comb filter for Y / C separation. Not available (even with a 2-line comb filter)
The H-th reference signal can be completely separated).

The above-mentioned reference signal can also be inserted in a 4-field sequence. In this case, an arithmetic circuit (Y / C separation circuit or Even in the case of having noise reduction, etc.), it is possible to prevent the color reference signal from being erroneously detected as the luminance reference signal by this arithmetic circuit and malfunction.

[0130]

According to the waveform equalization system of the present invention, when a composite video signal is input, a composite reference signal is inserted at a predetermined position of the composite video signal and a luminance signal and a chrominance signal are input. Is configured to insert the luminance and color reference signals obtained by separating the composite reference signal into predetermined positions in the luminance signal and the color signal, respectively, so that it is necessary to provide a reference signal generation circuit for each luminance and color reference signal. Since there is no need to provide a reference signal generating circuit for only the composite reference signal, the configuration of the reference signal generating circuit becomes small, which has the effect of reducing the cost, and there are multiple video signal transmission modes. Even when signals are transmitted through a plurality of transmission paths as a combination of signals (for example, VH for direct recording / reproduction of composite video signals). (Such as a VTR of a system that performs Y / C separation processing, or a component such as a VTR of a system other than this system that performs component recording / playback), and optimum distortion according to each transmission system. Can be corrected,
Further, it has an effect of removing any distortion such as linearity or gain of frequency characteristics, ringing, smear, and the like. Furthermore, the system of the present invention is applied to a transmission device such as a VTR having a variation in recording / reproducing transmission system for each product. In this case, there is an effect that it is possible to stably provide a transmission device having a constant quality that is not affected by variations in transmission characteristics between the transmission devices.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a waveform equalization system according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a reference signal inserting means which is a main part of the waveform equalization system according to the present invention.

FIG. 3 is a waveform diagram of a reference signal.

FIG. 4 is a waveform diagram of a recording luminance signal and a recording color signal in which a luminance reference signal and a color reference signal are inserted.

FIG. 5 is a configuration diagram of a comb filter provided in a reception side processing system of the waveform equalization system according to the present invention.

FIG. 6 is an input / output signal waveform diagram of the comb filter.

FIG. 7 is a configuration diagram of a first embodiment of waveform equalizing means which is a main part of the waveform equalizing system according to the present invention.

FIG. 8 is a configuration diagram of a second embodiment of waveform equalization means, which is a main part of the waveform equalization system according to the present invention.

FIG. 9 is an explanatory diagram for compensating for deterioration of transmission characteristics.

FIG. 10 is a waveform diagram of a recording luminance signal and a recording color signal in which a luminance reference signal and a color reference signal are inserted.

FIG. 11 is a configuration diagram for explaining a timing circuit.

FIG. 12 is a conceptual diagram of a transmission system for transmitting a video signal.

[Explanation of symbols]

1 waveform equalization system 10 CPU (detection means) 13, 20 transversal filter (filter means) A transmission side processing system B transmission path C reception side processing system D reference signal insertion means E waveform equalization means

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[Procedure amendment]

[Submission date] October 4, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0055

[Correction method] Change

[Correction content]

For example, when the two-line correlation type comb filter 4 shown in FIG. 5 is installed in the receiving side processing system C,
When a luminance signal in which one line before and after the luminance reference signal shown in FIG. 6A is not blanked is input to the filter 4, the signal shown in FIG. 6B is output.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction content]

As shown in FIG. 6B, the reproduction luminance reference signal is disturbed by the unspecified signal of the preceding one line (or the following one line), and unspecified distortion unrelated to the transmission characteristic is generated. Therefore, characteristic compensation cannot be performed well.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0057

[Correction method] Change

[Correction content]

In order to eliminate the above, FIG.
A luminance signal in which only one line before the luminance reference signal shown in (C) is blanked is input to the filter 4.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0058

[Correction method] Change

[Correction content]

Alternatively, the luminance signal in which one line before and after the luminance reference signal shown in FIG.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction content]

As a result, the signals shown in (D) and (F) of the same figure are output, and 1/2 of the luminance reference signal is output to 12 lines.
Only the reproduction luminance reference signal having the amplitude of 1 appears, and this signal can be characteristic-compensated without unspecified interference.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction content]

Further, when a 3-line correlation type comb filter is used as the noise canceller, similarly, FIG.
When the luminance signals shown in (A) and (C) are input, the reproduced luminance reference signal is disturbed and unspecified distortion unrelated to the transmission characteristic occurs, so that characteristic compensation cannot be performed well.
It is needless to say that when the luminance signal shown in FIG. 6E is input, the signal shown in FIG. 7F is output, and the reproduced luminance reference signal is not disturbed and good characteristic compensation can be performed.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0116

[Correction method] Change

[Correction content]

The reproduction luminance signal transmission characteristic compensating circuits 8A and 8B shown in FIG. 7 are of the FIR type, and the above description has been made in accordance therewith, but instead of this, the reproduction shown in FIG. Luminance signal transmission characteristic compensation circuit 24A, 24B
The IIR type may be used as described above. Further, both may be combined.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0118

[Correction method] Change

[Correction content]

In this case, since the reproduction luminance signal transmission characteristic compensating circuits 24A and 24B are IIR type, it is not possible to use the tap update equation using the above equation (1), but it is performed under the control of the CPU 10. The update of the taps for the transversal filters 13 and 20 is performed every several fields within the vertical blanking period, and the effective scanning section of the luminance signal and the chrominance signal, the color burst signal section,
Needless to say, this is not performed in the horizontal / vertical synchronization signal section.

[Procedure Amendment 9]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 10]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

[Procedure Amendment 11]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 12

[Correction method] Change

[Correction content]

[Fig. 12] ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 31, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0130

[Correction method] Change

[Correction content]

[0130]

According to the waveform equalization system of the present invention, when a composite video signal is input, a composite reference signal is inserted at a predetermined position of the composite video signal and a luminance signal and a chrominance signal are input. Is configured to insert the luminance and color reference signals obtained by separating the composite reference signal into predetermined positions in the luminance signal and the color signal, respectively, so that it is necessary to provide a reference signal generation circuit for each luminance and color reference signal. Since there is no need to provide a reference signal generating circuit for only the composite reference signal, the configuration of the reference signal generating circuit becomes small, which has the effect of reducing the cost, and there are multiple video signal transmission modes. Even when signals are transmitted through a plurality of transmission paths as a combination of signals (for example, VH for direct recording / reproduction of composite video signals). (Such as a VTR of a system that performs Y / C separation processing, or a component such as a VTR of a system other than this system that performs component recording / playback), and optimum distortion according to each transmission system. Can be corrected,
Further, it has an effect of removing any distortion such as linearity or gain of frequency characteristics, ringing, smear, and the like. Furthermore, the system of the present invention is applied to a transmission device such as a VTR having a variation in recording / reproducing transmission system for each product. In this case, there is an effect that it is possible to stably provide a transmission device having a constant quality that is not affected by variations in transmission characteristics between the transmission devices.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a waveform equalization system according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a reference signal inserting means which is a main part of the waveform equalization system according to the present invention.

FIG. 3 is a waveform diagram of a reference signal.

FIG. 4 is a waveform diagram of a recording luminance signal and a recording color signal in which a luminance reference signal and a color reference signal are inserted.

FIG. 5 is a configuration diagram of a comb filter provided in a reception side processing system of the waveform equalization system according to the present invention.

FIG. 6 is an input / output signal waveform diagram of the comb filter.

FIG. 7 is a configuration diagram of a first embodiment of waveform equalizing means which is a main part of the waveform equalizing system according to the present invention.

FIG. 8 is a configuration diagram of a second embodiment of waveform equalization means, which is a main part of the waveform equalization system according to the present invention.

FIG. 9 is an explanatory diagram for compensating for deterioration of transmission characteristics.

FIG. 10 is a waveform diagram of a recording luminance signal and a recording color signal in which a luminance reference signal and a color reference signal are inserted.

FIG. 11 is a configuration diagram for explaining a timing circuit.

FIG. 12 is a conceptual diagram of a transmission system for transmitting a video signal.

[Explanation of Codes] 1 waveform equalization system 10 CPU (detection means) 13, 20 transversal filter (filter means) A transmission side processing system B transmission path C reception side processing system D reference signal insertion means E waveform equalization means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 17/02 B 6942-5C

Claims (1)

[Claims] 1. A waveform equalization system for compensating for transmission distortion of a transmitted video signal, which is provided in a stage before a transmission side processing system, and when a composite video signal is input, a composite reference signal is used as the composite reference signal. When the luminance signal and the color signal are input at a specific position of the video signal, the luminance reference signal and the color reference signal obtained by separating the composite reference signal are specified in the luminance signal and the color signal. Reference signal inserting means for inserting into each position, and a reproduction luminance reference signal from the luminance signal transmitted via the receiving side processing system, and a reproduced color reference signal from the color signal transmitted via the receiving side processing system. And a luminance signal transmission system and color detected by the detection means for detecting the distortions respectively received by the reproduction luminance reference signal and the reproduction color reference signal during transmission. Waveform equalization system characterized by having a waveform equalizing means comprising a filter means for canceling each of the transmission distortion component of No. transmission system.