JPH0232695A - magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording and reproducing device, and in particular to a magnetic recording and reproducing device that performs digital signal processing by dividing signals into different bands such as a luminance signal and two color signals. Regarding.

[Conventional technology]

In the past, there have been examples in which skew-free variable speed playback is possible using variable delay means that controls the delay time through digital processing, such as the magnetic playback device described in Japanese Patent Application Laid-open No. 62-7277. No consideration is given to the delay time difference.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into account delay time differences when the luminance signal is divided into four color signals and subjected to filter processing, resulting in a problem of color shift.

An object of the present invention is to provide a magnetic recording and reproducing apparatus that processes digital signals separately for luminance signals and color signals, which can correct delay time differences between signal filters and obtain good images without color shift. The objective is to realize a recording/playback device.

[Means to solve the problem]

The above objective is achieved as follows. record.

During reproduction, this can be achieved by using control signal generating means that can vary the generation timing of a signal that controls a circuit that digitally processes each signal, or means that variably delays each signal.

[Operation] The control signal generation circuit or the variable delay means for each signal works to cancel out the difference in delay time between the filters of each signal, and determines the generation timing of the control signal or the delay time of each signal. , the reproduced video signal will not cause color shift.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
- As an example, the high-definition television (No. 7) shown in FIG.
This figure shows an example of a magnetic recording and reproducing device that can record and reproduce HD TV signals (hereinafter abbreviated as HD TV signals). In FIG. R), green (G), blue (B) input terminals,
4 is the horizontal synchronization signal of the HDTV signal (hereinafter referred to as HD)
input terminal.

5 is the vertical synchronization signal of the HDTV signal (hereinafter abbreviated as VD)
input terminals; 6 is a matrix circuit that converts the three primary color signals R, G, and B into a luminance signal Y and two color signals CW and CN; 1;
0.11.12 is a low-pass filter (hereinafter abbreviated as LPF), 20.21.22 is an A/D converter, 30 is a recording system luminance signal processing circuit, and 31.32 is a recording system luminance signal processing circuit 30. 40 is a recording system color signal processing circuit, 41 to 45 are components that constitute the recording system color signal processing circuit 40, 41 and 42 are vertical filters that limit the vertical band, and 43 is a line sequential conversion. circuit, 44.45 is memory,
50 is a recording system control signal generation circuit, 51 is a synchronization information generation circuit, 52 is a switching circuit, 60° 61 is a D/A converter, 7
0.71 is LPF, 80.81 is FM modulation circuit, 90.
91 is a recording amplifier, too, ioo '101, 10
1' is a magnetic head, 102 is a magnetic tape, 103 is a drum, 110.111 is a preamplifier, 120.121 is an FM demodulation circuit, 130.131 is an LPF, 140 is a synchronous separation circuit, 150.151 is an A/D converter , 160 is a reproduction system luminance signal processing circuit, 161 and 162 are memories forming the reproduction system luminance signal processing circuit 160, 170 is a reproduction system color signal processing circuit, and 171 to 173 are elements forming the reproduction system color signal processing circuit 170. So, 171.172 is memory, 1
73 is a color signal interpolation circuit, 180 is a reproduction system control signal generation circuit, an inverse matrix circuit that converts color signals CW and CN into three primary color signals R, G, and B, and 211 to 213 are outputs of three primary color signals R, G, and B, respectively. Terminal 214 is horizontal synchronization signal HD
The output terminal 215 is an output terminal for the vertical synchronization signal VD.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

The HD TV signals are supplied to input terminals 1, 2.3 in the form of three primary color signals R, G, and H, respectively. Next, the matrix circuit 6 converts the three primary color signals R, G, and B into the luminance signal Y and the two
It is converted into two color signals Cw and Cs. After that, Y, Cw
, CM signals have their signal bands limited by L P F 10, 11, 12, and A/D converters 20, 21, 22.
is converted into a digital signal by

The sampling clock WCKY of the luminance signal and the sampling clock WCKC of the two color signals Cw and C1f are set to WCKY=3·WCKC since in this embodiment, the bands of the luminance signal and the chrominance signal have a relationship of about 3:1. Each signal converted into a digital signal is input to a recording system luminance signal processing circuit 30 and a recording system color signal processing circuit 40, respectively, and predetermined signal processing is performed according to a control signal from a recording system control signal generation circuit 50. . Regarding this signal processing, please refer to the 4th section.
The rest will be explained in detail using figures.

Here, L P FIo, 11.12 is for removing aliasing components due to sampling when converting to a digital signal, and its limited band is determined by the signal band. In this embodiment, as shown in FIG. 2, the door degree A is 2.
0M1(z, two color signals CIl, CM is 7M7, so LPFIO is 20M, LPFll, 12
is the limited band of 7M1 (z. On the other hand, the delay time of the LPF varies depending on its limited band, and the delay time is larger in the narrow band. Here, the delay time of LPFIO is τy,L
If the delay time of PFII, 12 is τC, then τC〉τ
It becomes y. Therefore, when the signal shown in FIG. 3(a) is input, after passing through the LPF, it becomes the luminance signal Y and the color signal CW as shown in FIG. 3(b).

A deviation of the LPF delay time difference τM (=τC−τy) occurs at Cn. Regarding recording/reproduction system icon processing,
It is necessary to consider the above deviation. Therefore, in the recording system control signal generation circuit 50, the control signals for the luminance signal and the color signal are synchronized with the sampling clocks RCKY and RCKC based on the synchronization information (in this embodiment, HD and VD), and are different from each other by τM. It can be generated at the right time. The signals from the recording system control signal generation circuit 50 that control writing to the memory will be explained. Figure 3(c)
The two signals SPy and SPc shown in are the luminance signal 2, respectively.
This is a control signal indicating the start of color signal processing, and specifically, it is a control signal that indicates the start of color signal processing. This is a write start signal to the memories 44 and 45. As shown in FIG. 3(b), '! 4-degree signal 2
Even if there is a delay time difference τM of the LPF in the color signal, SPy, S
The generation timing of Pc is variable, and by generating SPy and SPc at timings that differ by τM from each other as shown in FIG. 3(C), both the luminance signal and the two color signals can be written into the memory regardless of the delay time difference between the filters. I can do it. In Figure 3(c), S
Although the signals Py and SPc are shown, it goes without saying that the timing of generation of other control signals such as memory address, reset, etc. changes in conjunction with SPy and SPc.

Next, recording system signal processing will be described in detail. In this embodiment, in order to record a wideband signal as shown in FIG.
(the period indicated by τ0 in Fig. 4(,)) is expanded by 1.8 times on the time axis, and as for the color signal, the above two color signals C
W (shown in Figure 4(b)) and CM (shown in Figure 4(c)
) shown in ) into a line-sequential equation, and then divides it into two channels and sets the valid period τ0 of one horizontal scanning period of the original signal to 0.
The time axis is compressed by 6 times, the luminance signal is time-division multiplexed, and horizontal synchronization information S of period τ3 is time-division multiplexed, resulting in two channels as shown in FIGS. 4(d) and (8). generates a recorded video signal. This horizontal synchronization information S consists of a negative polarity synchronization signal and a time-base reference signal such as a burst signal so that the synchronization information can be reliably separated during reproduction and the reproduced signal can be processed without time-base errors.

The above signal processing is performed as follows. The recording system luminance signal processing circuit 30 and the recording system color signal processing circuit 40 each include a memory for each channel.

The luminance signal Y is alternately written into the memories 31 and 32 line by line. On the other hand, the vertical bands of the two color signals CW and CM are controlled by vertical filters 41.42, and they are alternately written line by line in the memo 1J44.45. Further, the above-mentioned synchronization information S is generated by the synchronization information generation circuit 51
It is output from Here, the two channels of the luminance signals are simultaneously read out, and are appropriately switched by the switching circuit 52 in order to time-division multiplex them with the synchronization information S, as shown in FIG.
d) Generate two-channel recording signals as shown in (e).

The time axis expansion and compression at this time is realized as follows. Write clock WCKY of luminance signal to memory 31 and 32
(=luminance signal sampling clock), write clock WCKC (=chrominance signal sampling clock) to the color signal memory 44.45, read clock R
The relationship with CK is RCK = WCKY = WCKC-
As a result, the luminance signal Y is time-axis expanded by 1.8 times 1.8 0.6 , and the line-sequential color signal C[,8 is time-axis compressed by 0.6 times.

The two-channel recording signal obtained in the above manner is D/
After being converted into an analog signal by A converters 60 and 61, it is input to L P F2O,71. The recording signal bands of the two channels are the same, the limit bands of L P F2O, 71 are also the same, and there is no difference in delay time. After that, the FM conversion circuit 80.81 performs FM modulation, and the recording amplifier 90.9
1, the magnetic head too, 1ot (or 1
00', lot' is supplied. There are two sets of magnetic heads (100' and 100') facing each other at 180°.
, 101 and 101') are attached to the drum 103. In order to record a broadband signal, the drum 103 is rotated at, for example, 5.40 rpm to increase the head relative speed. The magnetic tape 102 is wound around the drum more than 1,800 times, and the video signals divided into the two channels are sequentially recorded on the magnetic tape 10IC by magnetic heads 100°100', 101, and 101' for each channel.

Next, during reproduction, the magnetic heads 100, 100'
The signals output from 101 and 101' are sent to preamplifier 1.
1 o.

The signal is input to FM demodulation circuits 120 and 121 via 111, and is subjected to FM demodulation. Then L P F 130.131
After being band-limited by , the signals are synchronously separated by a synchronous separation circuit 140 , and converted into digital signals by A/D converters 150 and 151 . After being converted into a digital signal,
The luminance No. 48 Y and the line sequential color signals C+ and s are respectively output from the reproduction system luminance signal processing circuit 160. Reproduction color signal processing circuit 170
is input. In the above reproduced signal processing circuit, the original HDT
In order to convert it to a V signal, the reverse processing to that during recording is performed. That is, the channels of the synchronization information added during recording are combined. Furthermore, since the color signal is subjected to line-sequential processing during recording, Cw and Cu are restored by interpolation processing.

The above processing is realized as follows. Reproduction system luminance signal processing circuit 160. The reproduction color signal processing circuit 170 has memories 161, 162, and 171 for each channel.
2, the synchronization information S is not written to the memory, and the color signal,
Only the luminance signal portion is written to each signal memory, and when read out, the compression rate of each signal is determined.

By reading with a clock according to the expansion rate, synchronization information can be removed and data can be expanded on the time axis.

Since color signals are processed line-sequentially during recording, interpolation circuit 1
In step 73, necessary interpolation processing is performed to obtain two color signals Cw and Cs.
restore. Each of the above signal processing circuits.

It operates according to a control signal from the reproduction system control signal generation circuit 180.

The luminance signal Y and two color signals C obtained as above
Convert w and CN to analog signals with D/A conversion @190.191.192, and LPF200°201,2
02 limits the band.

Here L P F 200 and L P F201.202
Like the recording system L PFIo, 11.12, the limited band is different. Therefore, the delay time τy of LPF 200, the delay time τC (τC
〉τy), then the delay time difference τ, ＜=τC−τy
), a time lag occurs between the luminance signal and the color signal. On the other hand, the above-mentioned time deviation can be corrected by generating the control signals for the luminance signal and the color signal at timings different by τM based on the synchronization information, as in the case of recording. This will be explained below using FIG. 5. R8Py and R5Pc shown in FIG. 5(a) are examples of reproduction system control signals,
Specifically, these are signals to start reading the luminance signal and two color signals from the memory. As shown in Figure 5(a), RS
By generating Py, RS Pc at timings different from each other by τM, the luminance signal and color signal (shown in FIG. 5(b)), which are read out from the memory with a time lag and with difficulty, are passed through the LPF, respectively. Therefore, it is possible to remove the time lag between the luminance signal and the two-color signal at the output of the LPF (as shown in FIG. 5(Q)). Here, R is used as a control signal.
Although 3Py and R8Pc are given as examples, other control signals,
For example, memory addresses and reset signals are also RS Py,
Needless to say, it is generated in conjunction with RS Pc.

The analog luminance signal Y and two color signals CWICN obtained in the above manner are converted into three primary color signals R, G, and B by an inverse 71 helix circuit 210, and output terminals 211.2
12.213 respectively.

In addition, the horizontal synchronization signal I (
D, the vertical synchronization signal VD is output, and the output terminal 214.
215, respectively.

Next, another embodiment will be described using the timing diagrams of FIG. 6 and FIGS. 7 and 8. 6(a) shows a second embodiment of the recording system luminance signal processing circuit 30, FIG. 6(b) shows a second embodiment of the recording system color signal processing circuit 40, and FIG. 6(c) shows the reproduction system. A second embodiment of the system luminance signal processing circuit 160, FIG. 6(d) is a diagram showing a second embodiment of the reproduction system color signal processing circuit 170, and the other parts are the same as the block diagram of FIG. And 3 in 1 figure
3.46.163.174 is a variable delay circuit.

The operation of the recording system will be explained using FIG. Luminance signal and color signal input as described above (shown in Figure 7(a))
is L P FIo, 11.12. A time lag τM occurs due to the delay time difference (as shown in FIG. 7(b)). Here, using the variable delay circuits 33 and 46, it is possible to correct the above-mentioned temporal shift between the luminance signal and the color signal. That is, the relationship between the delay amount τoz of the variable delay circuit 33 and the delay amount τoc of the variable delay circuit 46 is τM=τl1l.
Figure 7 (
As shown in c), the time difference τ between the luminance signal and the color signal can be removed. Therefore, in this case, Fig. 3(c)
The generation timings of the memory control signals SPy and SPc shown in FIG. 7 may be constant (as shown in FIG. 7(d)).

On the other hand, also in the reproduction system, the above-mentioned time difference between the luminance signal and the color signal can be corrected by 1 using variable delay circuits 163 and 174. That is, control No. 42 R shown in FIG. 8(a)
For the luminance signal and color signal (shown in FIG. 8(b)) read out from the memory according to S Py and RS Pc, the approximate extension amount τ111 of the variable delay circuit 163 and the delay amount of the variable delay circuit 174 are calculated. The relationship of τpc is set so that τM=τoy−τDC. As a result, the output of the variable delay circuit has a time difference of τM between the luminance signal and the chrominance signal (2) shown in FIG. '', the time lag is corrected as shown in FIG. 8(d).

Here, the variable delay circuit is a digital delay means such as a shift register or a line memory. Further, in the first embodiment, a variable generation means for each control signal was used, and in the second embodiment, a variable delay circuit for the video signal was used. , the other one can be used for fine adjustment to obtain the same effect.

As described above, the time difference between the luminance signal and the color signal is corrected by digitally managing the delay time of the analog LPF, but whereas the delay time of the analog LPF is continuous, , what can be digitally managed is discrete. In this case, the finer the minimum variable range,
Errors can be reduced for continuous delay amounts.

Therefore, when the sampling clock rates of each (No. 8) are different as in this embodiment, the control signal generation timing of the luminance signal system and the delay time of the variable delay circuit are adjusted using the sampling clock RCKY of the luminance signal, and the sampling clock RCKY of the chrominance signal system is used. The control signal generation timing and the delay time of the variable delay circuit can be adjusted independently using the color signal sampling clock RCKC (in this embodiment, RCKY=3.RCKC), which is the relatively highest clock. , the sampling clock of a wider band luminance signal can be adjusted in units of RCKY.

Next, we will discuss the case where the sampling clock rate is high and the digital variable element or control signal generation circuit cannot handle it, so phase division is used for processing. Phase division allows the processing clock rate to be lowered. - As an example, consider a case where the luminance signal Y is processed by two-phase division, and the color signals Cv and CN are processed without phase division. FIG. 9(a) is a diagram showing the sampling phases of the luminance signal Y and the color signals Cw and CFt when they are A/D converted after passing through the LPFIo and 11.12 in the recording system. In the figure, the points indicated by black circles are data that should originally be at the same position for the luminance signal Y and color signals CW and CM, but LPFIO and LPFll, 12
There is a difference of 1M due to the delay time difference. FIG. 9(b) shows a case where the luminance signal Y is divided into two phases for signal processing in this state.

Here, when correcting the time difference using a variable delay circuit, the brightness signal Y is adjusted using the brightness signal sampling clock T, RCKY/2, and the color signal system is adjusted using the color signal sampling clock RCKC. By using the brightness signal Y and the color signal Cw, each can be adjusted independently.
It is possible to correct the time and misalignment of Cs as shown in FIG. 9 (Q), and it is relatively the highest clock. It can be adjusted in units of the sampling clock RCKY of a wider band luminance signal. In this embodiment, an example was given in which the luminance signal is divided into two phases and the color signal is not divided into phases, but when the luminance signal is divided into N phases (N is a natural number) and one Buddhist monk name is divided into M phases (M is a natural number). The present invention is also applicable.

In this embodiment, the time difference due to the delay time difference of the analog filter has been described, but the time difference caused by the different digital No. 43 processing of the luminance signal 9 can also be corrected in the same way. In addition, in this example, 2
Taking channel division recording as an example, L channel division record 1
(L is a natural number), the present invention can be applied without any change.

〔Effect of the invention〕

As described above, the present invention has the following effects: 1. It is possible to realize a magnetic recording and reproducing apparatus that can obtain a good screen without color shift regardless of the delay time difference of analog filters.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram explaining a high-definition television system, and FIG. 3 is a block diagram showing an embodiment of the present invention. 5 is a diagram for explaining the operation of the embodiment shown in FIG. 1, FIG. 4 is a diagram for explaining the recording method of this embodiment, FIG. 6 is a block diagram showing the main parts of another embodiment, and FIG. figure. 1-5...Input terminal, 211-215...Output terminal, 10-12.70.71.130.131.200
~202...Low pass filter, 20~22.150.151...A/D converter. 6...71-RISC circuit, 30... Recording system luminance signal processing circuit, 40... Recording system color signal processing circuit, 50... Recording system control signal generation circuit. 33, 46.163.174... variable delay circuit, 16
0: Reproduction system luminance signal processing circuit, 170: Reproduction system color signal processing circuit, 180: Reproduction system control signal generation circuit, 60, 61.1
90-192...D/A converter, 210...Inverse matrix circuit. The first country

Claims (1)

[Claims] 1. In a device that multiplexes a luminance signal and a chrominance signal of a video signal in a time division manner to record and reproduce the luminance signal, the luminance signal is passed through a first filter to a first sampling clock having a predetermined frequency. a first A/D conversion means for converting into a digital signal;
a second A/D conversion means for converting the color signal into a digital signal using a second sampling clock having a lower frequency than the first sampling clock via a second filter having a different pass band from the first filter; , first A/D
a first writing means for sequentially writing the digital signal from the conversion means in units of horizontal scanning lines into the first memory at a first sampling clock; and a first writing means for writing the digital signals from the second A/D conversion means in units of horizontal scanning lines. a second write means for sequentially writing into a second memory using a second sampling clock; a first write control signal for controlling the first write; and a second write control signal for controlling the second write; D/A conversion that reads the digital signals alternately from the first and second memories, generates a time-division multiplexed signal of the luminance signal and the color signal, and converts it into an analog signal. and the write control signal generating means generates the first write control signal at a first sampling clock period with a time difference corresponding to a time difference occurring between the first filter and the second filter. A magnetic recording/reproducing apparatus characterized in that the second write control signal is adjusted and generated at a second sampling clock cycle. 2. In the above magnetic recording/reproducing device, a first A/D conversion means converts a luminance signal into a digital signal via a first filter using a first sampling clock of a predetermined frequency; a second A/D converter that converts the digital signal into a digital signal using a second sampling clock having a lower frequency than the first sampling clock through a second filter having a different pass band from the first A/D converter;
a first digital variable delay means for delaying the digital signal from the conversion means in synchronization with the first sampling clock; and a first digital variable delay means for delaying the digital signal from the second A/D conversion means in synchronization with the second sampling clock. second to let
a digital variable delay means, a first writing means for sequentially writing the digital signal from the first digital variable delay means into the first memory in units of a horizontal scanning period using a first sampling clock, and a second digital variable delay means. a second writing means for sequentially writing a digital signal from the means into a second memory in units of a horizontal scanning period using a second sampling clock; a first write control signal for controlling the first writing; means for generating a second write control signal for controlling writing; and means for alternately reading digital signals from the first and second memories to generate a time-division multiplexed signal of a luminance signal and a color signal; and D/A conversion means for converting it into an analog signal, and the first and second digital variable delay means have a time difference corresponding to a time difference occurring between the first filter and the second filter. , the first digital variable delay means adjusts the delay time in the first sampling clock period, and the second digital variable delay means adjusts the delay time in the second sampling clock period, thereby adjusting the luminance signal and the color signal. 2. The magnetic recording/reproducing apparatus according to claim 1, wherein the magnetic recording/reproducing apparatus is delayed. 3. In the magnetic recording and reproducing device, A/D conversion means converts the reproduced video signal into a digital signal using a clock of a predetermined frequency, and the digital signal from the A/D conversion means is used for a luminance signal and a color signal. a means for distributing and writing the luminance signal into each memory, a first reading means for reading out the luminance signal from each memory in synchronization with a first sampling clock for the luminance signal, and a second sampling clock for the chrominance signal for the chrominance signal. a second readout means for reading in synchronization with the first readout, a means for generating a first readout control signal for controlling the first readout, a second readout control signal for controlling the second readout, and a luminance signal memory. a first D/A conversion means for converting a digital signal from the color signal memory into an analog signal; a second D/A conversion means for converting a digital signal from the color signal memory into an analog signal; a first filter that limits the band of the output from the A conversion means;
The second D/A conversion means has a second filter having a different pass band from the first filter that limits the band of the output from the second D/A conversion means, and the readout control signal generation means has a second filter that limits the band of the output from the second D/A conversion means. The first readout control signal is adjusted with the first sampling clock period, and the second readout control signal is adjusted with the second sampling clock period, with a time difference corresponding to the time difference caused by the second filter. The magnetic recording and reproducing apparatus according to claim 1, characterized in that: 4. In the magnetic recording and reproducing device, an A/D conversion means converts the reproduced video signal into a digital signal using a clock of a predetermined frequency, and the digital signal from the A/D conversion means is used for a luminance signal and a color signal. a means for distributing and writing the luminance signal into each memory, a first reading means for reading out the luminance signal from each memory in synchronization with a first sampling clock for the luminance signal, and a second sampling clock for the chrominance signal for the chrominance signal. a second readout means for reading in synchronization with the first readout, a means for generating a first readout control signal for controlling the first readout, a second readout control signal for controlling the second readout, and a luminance signal memory. a first digital variable delay means for delaying a digital signal from the color signal memory in synchronization with a first sampling clock; and a second digital variable delay means for delaying a digital signal from the color signal memory in synchronization with a second sampling clock. a delay means, a first D/A conversion means for converting the digital signal from the first digital variable delay means into an analog signal, and a first D/A conversion means for converting the digital signal from the second digital variable delay means into an analog signal. a first filter that limits the band of the output from the first D/A converter; and a first filter that limits the band of the output from the second D/A converter. a second filter having a different passband from the first filter; the first and second digital variable delay means have a time difference corresponding to a time difference occurring between the first filter and the second filter; The first digital variable delay means adjusts the delay time in the first sampling clock period, and the second digital variable delay means adjusts the delay time in the second sampling clock period to delay the luminance signal and the color signal. 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording and reproducing apparatus comprises: 5. In the above magnetic recording/reproducing device that processes the luminance signal by dividing it into N phases (N is a natural number) and dividing the color signal into M phases (M is a natural number), the means for generating the control signal is configured to generate a first control signal. is 1/N period of the first sampling clock, and the second
2. The magnetic recording and reproducing apparatus according to claim 1, wherein the control signal is generated by adjusting the period of 1/M of the second sampling clock. 6. In the above magnetic recording and reproducing apparatus that processes signals by dividing the luminance signal into N phases (N is a natural number) and dividing the chrominance signal into M phases (M is a natural number), the first digital variable delay means is connected to the first sampling clock. 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the second digital variable delay means adjusts at a 1/M period of the second sampling clock.