JPS61108265A - Multi-scanning type receiver - Google Patents

Abstract

PURPOSE:To obtain always a prescribed display picture independently of a vertical frequency by using a signal from a sawtooth wave oscillator in which the amplitude of the sawtooth wave is controlled to a prescribed value so as to apply vertical deflection. CONSTITUTION:A vertical synchronizing signal from a separation circuit is fed to the sawtooth wave oscillator 6 being a component of a vertical deflection circuit 8 through an input terminal 60, and a sawtooth wave is generated by, e.g., charging/discharging a capacitor 62 by a current from a current source 63. Further, a signal from the input terminal 60 is fed to a count terminal of an up-down counter 65, the counted data is fed to a DA converting circuit 67, where the data is converted into an analog quantity, which controls the current source 63. Thus, the sawtooth wave whose peak value (amplitude) is controlled into a prescribed voltage independently of the frequency of the vertical synchronizing signal is extracted from the oscillator 1.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable not only to reception of IMM Fumin-style television broadcasting, but also to reception of television broadcasting using different broadcasting methods, and display of video signals from computers, etc. The present invention relates to a multi-scanning receiver capable of receiving video signals having different vertical frequencies and vertical deflection widths.

[Conventional technology]

For example, in an NTSC television signal, the vertical frequency is approximately 601 Iz and the horizontal frequency is approximately 15.75 kjlz.
The image is formed. In contrast, the so-called CCI
I? In the force formula, the vertical frequency becomes 5011z -ζ.

Furthermore, a conversion device has been proposed that doubles the number of scanning lines through arithmetic processing or the like to improve the quality of the received image. When this device is used, the output signal has a vertical frequency of, for example, 6011z, and a horizontal frequency of about 31.
It has become 5kllz.

In addition, some so-called high-resolution display computer output signals have a horizontal frequency of about 25 kllzO. Furthermore, in so-called Western quality television, the horizontal frequency is scheduled to be approximately 33.75kllz.

A multi-scanning receiver has been proposed that allows a single device to receive various signals having different vertical and horizontal frequencies.

By the way, in conventional television receivers, the vertical deflection circuit generally uses a constant slope sawtooth wave to form a deflection current.

That is, for example, in FIG. 5, input terminal A (2 (11)
is supplied with a vertical synchronizing signal, and this signal is fed to the sawtooth wave oscillator (202).
203) is charged and discharged by the current of the current source (204') (a sawtooth wave with a constant slope is formed. This signal is output to the output circuit <2).
05) to the vertical deflection coke (206). Furthermore, a series circuit of a figure-8 correction capacitor (207) and a resistor (208) is connected in series to this deflection yoke (206), and a vertical deflection volume (209) is connected in parallel to this resistor (2 (18)). A voltage divider circuit containing is connected,
This amount) ball output is fed back to the output circuit vpt (205).

According to this circuit, a vertical deflection signal with a constant slope is formed and supplied to the vertical deflection yoke (206).
- The width of the vertical deflection at the inner surface can be controlled by adjusting the width of the beam (209).

However, in this device, for example, NTSC system and CC
When attempting to receive IR television broadcasting, the vertical frequency is changed from approximately 6011z to 5011z. In that case, in the lid device, the amplitude of the sawtooth wave changes when the frequency is changed due to the constant slope. That is, when a sawtooth wave as shown in FIG. 6A is formed at about 6011z, the amplitude becomes large at 5011y because it is a constant slope as shown in B.

For this reason, conventionally, when the frequency was changed, the volume (
209) and readjust the screen size.

Furthermore, when displaying the output of a computer, for example, in conventional TV broadcast reception, so-called overscanning is performed in order to display both images to the fullest extent of the display screen, whereas with the output of a computer, the corners of the display screen are Underscanning is performed to display the entire image completely. For this reason, in standard television broadcasting, the vertical amplitude is determined by taking the number of horizontal scanning lines as, for example, a period of 26262.5, an image of 229, and an overscan of 5%, whereas for example, in the output of a computer with a horizontal frequency of 25 kHz, the vertical scanning time is plane and the vertical amplitude is varied.

Even in this case, it is necessary to readjust the vertical deflection width of the human input signal accordingly.

[Problem that the invention seeks to solve]

1-A multi-scanning receiver as described above has been proposed.

However, in this device, if vertical deflection is performed with the same configuration as used in a conventional television receiver, if the vertical frequency is different or if you try to change the display range of the screen, There was a problem in that the vertical deflection volume had to be readjusted each time.

Means for Solving Problem yjj] The present invention provides a method for detecting the amplitude of an output signal and controlling the amplitude to a predetermined value in a multi-scanning receiver that receives a plurality of video signals with different vertical frequencies. This is a multi-scanning type receiver in which a sawtooth wave oscillator (61) with a vertical period of (101) is provided, and vertical deflection is performed by the output of this sawtooth wave oscillator (61).

[Effect]

According to this device, vertical deflection is performed using a signal from a sawtooth wave oscillator in which the amplitude of the sawtooth wave is controlled in a predetermined manner, so that a predetermined display signal can be generated regardless of the vertical frequency. Obtainable.

(Embodiment) First, a multi-scanning receiver proposed by the applicant of the present application will be described.

Figure 3 shows the overall block diagram. In this figure, a typical television broadcast tuner or video tape recorder,
When receiving a normal video signal from a video disc player, satellite broadcast tuner, or some personal computers, the video signal supplied to the input terminal (+1) passes through the RGB process circuit ( 3) to form three primary color signals. In addition, the video/RGB switching signal supplied to the input terminal (4) is supplied to the process circuit (3), whereby the three primary color signals from the selected video signal are output to the output circuit (5).
) is supplied to the cathode ray tube (6).

In addition, the video signal from the input terminal (11) is connected to the sync separation circuit (
7), and the vertical and horizontal synchronization signals are separated.

Furthermore, the switching signal from the input terminal (4) is connected to the park circuit (7).
The vertical deflection signal from the selected video signal is supplied to the vertical deflection circuit (8), and the formed vertical deflection signal is applied to the vertical deflection yoke (6) of the cathode ray tube (6).
9). Also, the horizontal synchronizing signal from the video signal selected by the separation circuit (7) is supplied to the AFC circuit (1/#ioo).
The signal from this AFC circuit αψ is supplied to the horizontal oscillation circuit 1m (11), and the control signal at the time of passing from the mode detection circuit 1/8 (12) is supplied to the oscillation circuit 17.
K(11). And this oscillation circuit (11)
is supplied to the horizontal deflection circuit (13), and the formed horizontal deflection signal is sent to the horizontal deflection yoke (6) of the cathode ray tube (6).
14). Furthermore, the signal from the deflection circuit (13) is transmitted to a high voltage source such as a fly bank transformer/1-times l#1 (
15) and the formed commercial signal is supplied to the high voltage terminal (16) of the cathode ray tube (6), while a part of the signal is
F CIi”!IIIj4001.

Furthermore, the commercial power from the power supply input (17) is supplied to the power supply circuit (41), and in response to the signal from the detection circuit II (12), the current voltage is applied to the horizontal deflection circuit (13). A commercial power source from a human power source (17) is supplied to another power supply circuit (19), and the voltage formed is supplied to the other circuits.

This allows normal video signal reception. On the other hand, when receiving digital or analog RGB signals from some personal computers, so-called captain demodulators, teletext demodulators, or scan converters, input terminals (20R) (20G)
(20B') Supplied digital RGB signal and input terminal (21R) (21G) (21B)
The analog RGB signal supplied to
22) and the analog signal from the input terminal (24).
Selected by digital switching signal and RGB process circuit (
3), is selected by the switching signal from the input terminal (4), and is supplied to the output circuit (51).

In addition, a digital synchronization signal from the input terminal (<2O8) and an analog synchronization signal from the input terminal (215) are supplied to the changeover switch (23), which are selected by the changeover signal from the human power terminal (24) and synchronized. It is supplied to the separation circuit (7), selected by the switching signal from the input terminal (4), and supplied to the vertical deflection circuit (8) and the AFC circuit (Im). The signal from is supplied to the mode detection circuit 6 (12), a control signal corresponding to the frequency of the horizontal synchronization signal is formed, and is supplied to the horizontal oscillation circuit (moon), horizontal deflection circuit (13), and power supply circuit (18). be done.

This improves the reception of digital or analog PCB signals. Furthermore, the above-mentioned normal video 4I8″f
When performing so-called superimposed image reception in which RGB signals are displayed by superimposing them on J, the switching signal supplied to the input terminal (4) is set to RG B %-, and the switching signal supplied to the input terminal (25) is The Ys signal indicating the position of the supplied superimposed signal and the YII signal indicating the superimposed range are connected to the RG B circuit (1 process circuit).
3), and switching between a video signal and an RGB signal is performed between these Ys and Ym signals.

Various signals are received in the manner described above.

Further, in the secondary device, the horizontal deflection system is specifically constructed as described above. In Figure 4, park time W817
The horizontal synchronization signal from 1 is supplied to a frequency-voltage conversion circuit (FVC,) (31) constituting the mode detection circuit (12) to form a voltage according to the horizontal frequency. Limiter circuit (32), buffer (B) where this voltage determines the lower limit
The signal is supplied through an amplifier (33) to a voltage controlled oscillator (VCO) (34) that constitutes a horizontal oscillation circuit (11). The oscillation output of this VCO (34) is supplied through a drive circuit (35) to a switching transistor (36) constituting a horizontal deflection circuit (13).

In addition, the voltage from the FVC (31) sets the upper and lower limits through a limiter circuit (37) and a gain control (GC) amplifier (38) to form the power supply circuit (18). is supplied to The output voltage of the power supply circuit (39) is fed back to the amplifier (38) through the voltage divider circuit (40) to stabilize the output voltage.

This output voltage is supplied to a flyback transformer (41).

A transistor (36) is connected in series to this flyback transformer (41). Also, this transistor (36
) is connected in parallel with a damper diode (42), a resonant capacitor (43), and a series circuit of a horizontal deflection yoke (14) and a figure-eight correction capacitor (44).

In addition, the horizontal synchronizing signal is supplied to the detection circuit (45) constituting the AFC circuit 00, and the transistor (36
) is supplied to the detection circuit II (45) to form an AFC signal. This signal is passed through the low-pass filter (L P F) (47)
It is supplied to the control terminal of the VCO (34) through the VCO (34).

Furthermore, a switch circuit (
A capacitor (4!J) (50) is connected through the capacitor (4!J) (48). In addition, in parallel with the figure 8 correction capacitor (44),
Capacitor (52) (5) through switch circuit (51)
3) is connected. Also, the voltage from FVC (3]) is
For example, the signal 72 is supplied to a comparison circuit (54) with values corresponding to voltages of 20kllz and 30kHz of the input horizontal frequency.
A three-value comparison output corresponding to each range of 0kllz or less, 20 to 30kHz, and 30kllz or more is formed, and 21 switches built in each of the switch circuits (48)' and (51) are activated according to this comparison output. Control is performed so that both are turned off or one of them is turned on.

Thus, in this horizontal deflection system, vc.

(34) 15 to 34k in synchronization with the input horizontal synchronization signal
An oscillation signal that changes to llz is formed to perform horizontal deflection, and a voltage that changes from 58 to 123 volts, for example, depending on the horizontal frequency is generated in the power supply circuit (39) to change the amplitude of the horizontal deflection. Control is performed to keep it constant. In addition, capacitors (49), (50), and (52) and (53) are connected in parallel to the resonance capacitor (43) and the figure-8 correction capacitor (44) depending on the horizontal frequency range, and the characteristics of each capacitor are corrected. be exposed.

In the above-described apparatus, the vertical deflection system is configured as follows. In FIG. 1, the vertical synchronization signal from the separation circuit (7) is transmitted to the vertical deflection circuit (8) through the input terminal (60).
For example, a sawtooth wave is generated by charging and discharging a capacitor (62) with a current from a current source (63). This sawtooth wave has amplitudes of predetermined first and second amplitudes (first amplitude>second amplitude).
A comparator circuit (64a) that detects when the amplitude is larger than
(64b). Also input terminal (60)
The signal from the up/down counter (tJnc) (
65), and is supplied to the counting terminal of the child series comparison circuit (64a
) is supplied to the control terminal of the IJDC (65). Furthermore, the outputs of the comparison circuits (64a) (64h) are exclusive OR times l? R (66), and its output is supplied to the inhibit terminal of UDC (65). The count data of each tJDc (65) is supplied to a DA conversion circuit (DAC) (67), and a current source (63) is controlled by the converted analog value.

As a result, when the amplitude from the oscillator (marked) is below the comparison level of the comparator circuit (64h) as shown by the solid line a in Figure 2, a control signal to increase the count is supplied to tJDc (65), and the d1 count data is is increased to increase the conversion output of the DAC (67), and the current value of the current source (63) is increased to expand the amplitude of the sawtooth wave.

Also, when the amplitude from the oscillator (61) is between the comparison levels of the comparison circuits (64a) and (64b) as shown by the solid line in the figure, the output of the exclusive OR circuit (66) is the inhibit terminal of the UDC (65). is supplied and counting is prohibited. Furthermore, when the amplitude from the oscillator (61) is equal to or higher than the comparison level of the comparator circuit (64c) as shown by the solid line C in the figure, a control signal to reduce the number of stitches is supplied to the UDC (65), the count data is decreased, and the DAC The conversion output of (67) is reduced and the current value of current source (63) is reduced to reduce the amplitude of the sawtooth wave.

Therefore, a sawtooth wave whose peak value (amplitude) is controlled within a predetermined voltage range is extracted from the oscillator (61), regardless of the frequency of the 111th vertical interval. This sawtooth wave is the output circuit (
41 (supplied to the vertical deflection yoke (9) through the deflection yoke (9)).
69), a series circuit of a resistor (70) is connected, and a preset volume (71a) is connected in parallel to this resistor (70).
) (71b) is connected. This volume (
The divided voltage outputs of 71a and 71b are selected by a changeover switch (72) and supplied to an output circuit (68).

In addition, a switching signal from the input terminal (41 (24)) is supplied to the selection control circuit (73). Here, the switching signal supplied to the input terminal (4) is, for example, 1", RGB, RGB, etc. when selecting a video signal. When selecting a signal, the switching signal (i'?) is set to "1" and is supplied to the input terminal (24), for example, "1" when selecting an analog signal.

Set to "0" when selecting a digital signal.

If the 'ζRGB signal is selected by the selection control circuit (73) and the analog signal or digital signal is
The status of ltJN is determined.

Furthermore, a switch (74) to preset the analog signal
and Swisso f-(75) which pre-centres digital signals.
are provided, and when the states of these switches (74) and (75) match the content determined by the selection control circuit (73), a control signal is output from the selection control circuit (73). This signal is supplied to the control terminal of the changeover switch circuit (72).

Therefore, in this device ζ, normally the switch circuit (72)
is switched to the volume (71a) side, for example, and the vertical deflection width is set to the size set by the preset volume (71a). On the other hand, the switch (74) (
When the analog signal and/or digital signal set in step 75) matches the signal determined from the input terminals (4) and (24), the switch b! Ji
(72) Kaho'J Neem (71b) 2 is switched, and the vertical deflection width is set to, for example, a second size with a display range of 90% or more.

This allows, for example, to change the vertical deflection width when an analog or digital signal supplied from a computer is selected, and to make this change only for analog signals, only for digital signals, or both. Can be set arbitrarily. Further, this change can be made automatically in conjunction with the selection of the video signal by setting the switches (74) and (75) in advance.

In the above example, the vertical deflection width was set to two types: overscan and underscan, but the volume (7
A plurality of 1b) may be provided so that three or more settings can be made, and these may be switched according to the selection of the video signal.

In this way, the vertical deflection width is always adjusted to a predetermined size of 1 lil, but according to the circuit described above, since the amplitude control is divided into two locations, the amplitude versus frequency characteristic becomes constant, and the output circuit (68) Since the input has a constant amplitude, the output circuit (
A desired effective display rate can be obtained with a relatively small change in the voltage to current gain of 68), and the operation is stabilized. In addition, in the case of a relaxation oscillator, a good period cannot be obtained unless the vertical hold is moved in accordance with changes in the input frequency, but the above-described circuit allows the removal of the vertical hold.

〔Effect of the invention〕

According to the present invention, since vertical deflection is performed using a signal from a sawtooth wave oscillator in which the amplitude of the sawtooth wave is controlled to a predetermined value, it is possible to always obtain a predetermined display image regardless of the vertical frequency. Now you can.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an example of the present invention, FIGS. 2 to 4 are diagrams for explaining the same, and FIGS. 5 and 6 are diagrams for explaining a conventional apparatus. (60) is an input terminal, (61) is a sawtooth wave oscillator, (6
4a) (64b) is a comparison circuit, (65) is an up/down counter, (67) is a D/A conversion circuit, (68
) is the output circuit.

Claims (1)

[Claims] In a multi-scanning receiver that receives a plurality of video signals with different vertical frequencies, a sawtooth wave oscillator with a vertical period that detects the amplitude of an output signal and controls the amplitude to a predetermined value is provided. A multi-scanning receiver that performs vertical deflection using the output of a wave oscillator.