JPS6156676B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synchronization detection device used when connecting a television game, a VTR, etc. to a television receiver.

Conventionally, the output signals of video games, VTRs, etc. were RF.
A converter converted it to a VHF or UHF RF signal, which was then connected to a TV set in a typical home. At this time, a channel that is not used in the area is usually selected as the channel for the RF signal that is the output signal of the VTR or the like. Therefore,
When playing back a VTR, etc., it is necessary to adjust the channel knob of the TV receiver to match the channel of the RF signal, which is the output signal of the VTR, which not only takes time, but also causes the user to forget the channel number to match. There are some inconveniences when using a VTR.
This was one of the reasons why it was difficult to use.

This invention solves the above-mentioned drawbacks of the conventional technology, and detects which channel the tuner of the television receiver in use is suitable for, and automatically sends out an RF signal suitable for that channel from a VTR, etc. It is. The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a tuning detection device according to the present invention. In this configuration, when receiving a broadcast with the television receiver 1, the switch 2 is connected to the terminal a side and the received signal from the broadcast receiving antenna 3 is received via the directional coupler 4.
Next, when you want to watch a VTR, connect switch 2 to terminal b and press an operation start button (not shown) that is linked to the VTR's power switch, for example, to apply a trigger pulse to input terminal 5a. Ru. When a trigger pulse is applied to the input terminal 5a, a command pulse is sent from the control circuit 6.
The signal is applied to the RF signal generator 7, and the RF signal generator 7 generates RF signals for channels A, B, C, . . . in this order. This RF signal is applied to a modulator 8 and is modulated by a video signal from a test signal source 10 applied via a switch 9 connected to terminal C. The RF signal modulated by the modulator 8 is given to the television receiver 1 via the switch 2.

Now, TV receiver 1 is on channel B,
If the RF signal generator 7 is not tuned to channel B, the phase of the deflection system of the television receiver 1 will be completely random due to the influence of noise. Therefore, the synchronization pulse of the television receiver 1 induced by the synchronization antenna 11 has no relation to the synchronization signal of the test signal source 10, and therefore is applied via the synchronization pulse from the synchronization antenna 11 and the synchronization separation circuit 12. The output of the phase detector 13 that detects the phase of the synchronization pulse from the test signal source 10 fluctuates and includes an alternating current component. This AC output is rectified by a rectifier circuit 15 via a high-pass filter 14. When the rectifier circuit 15 produces an AC output, the level discrimination circuit 16 is set to have no output, and the control circuit 6
No signal is applied to the input terminal 5b of the RF signal generator 7, and the control circuit 6 continues to output sequentially and sequentially switches channels A, B, C, . . . of the RF signal generator 7. In this way, when the RF signal generator 7 becomes channel B, the deflection system of the television receiver 1 is synchronized with the synchronization signal of the test signal source 10. Therefore, the output of the phase detector 13 is substantially constant and does not include an alternating current component. Therefore, since the level discrimination circuit 16 generates an output and applies it to the input terminal 5b, the control circuit 6 controls the channels A,
Canceling the switching operation of B, C, ......
The RF signal generator 7 continues to generate the channel B signal. In this state, switch 9 is connected to terminal c.
When switching from to terminal d, a video signal from the video signal source 17 is applied to the modulator 8, and an RF television signal corresponding to this signal is generated and applied to the television receiver 1. In this way, the output image of the video signal source 17 of the VTR is projected on the screen of the television receiver 1. In addition, terminal c of switch 9
It is obvious that the configuration can be such that switching from to terminal d can be automatically performed by the output of the level discrimination circuit 16. In addition, the test signal source 10 and the video signal source 17 are used together, and the test signal source 10
may be abolished. However, if the test signal source 10 is separate and its signals are slightly out of synchronization from the standard, it is possible to determine whether the television receiver 1 is synchronized with the broadcast wave or with the test signal source 10. becomes easier to understand. If the synchronization signal of the test signal source 10 is almost the same as the broadcast wave, if the television receiver 1 is synchronized with the broadcast wave leaking from the switch 2, the AC output of the phase detector 13 This is because the cycle becomes longer and the operation of the rectifier circuit 15 and level discrimination circuit 16 becomes less reliable. However, while the frequency of the horizontal synchronization signal of the television receiver 1 is 15.75KHz, the frequency of the synchronization signal of the test signal source 10 is, for example,
If the synchronization is slightly shifted, such as at 16KHz, and the TV receiver 1 is compatible with the broadcast channel leaking from the switch 2, the cycle of the AC component of the output of the phase detector 13 will be shortened, and the rectification will be delayed. As the output voltage of the circuit 15 becomes higher, the operation of the level discrimination circuit 16 becomes more reliable. The synchronization signal to be compared by the phase detector 13 may be either horizontal or vertical.
It may also be a color subcarrier or an audio carrier (these are referred to as timing signals).
In this case, it is desirable to provide a band amplifier suitable for a color subcarrier or a voice carrier between the synchronous antenna 11 and the phase detector 13.
Furthermore, it is necessary to provide a color subcarrier or audio carrier reproducing circuit in place of the synchronization separation circuit 12.

Furthermore, the synchronous antenna 11 may be wire-shaped, rod-shaped, or coil-shaped instead of wire-mesh-shaped.
Also, a part of the housing of a VTR, video game, etc. may be used, and these are collectively referred to as antennas.
Further, the synchronous pulse induced in the synchronous antenna 11 may be at least about 0.1V. Furthermore, the switch 9 may be a semiconductor switch, a rotary switch or a group of relays. Furthermore, the control circuit 6 can be composed of a well-known shift register, an astable multivibrator, or a gate. Furthermore, instead of placing the synchronous antenna 11 near the television receiver 1, a trap circuit as shown in FIG.
A color chorus carrier or a voice carrier may be extracted.

FIG. 2 is an electrical wiring diagram showing an embodiment of the trap circuit. In the configuration, 18 is a power supply side terminal connected to the power supply side of the power supply line, 19 is a load side terminal connected to the load side of the power supply line, Reference numerals 20 and 21 indicate chiyoke coils, 22 and 23 indicate capacitors, and 24 indicates an output terminal for taking out a synchronizing pulse, a color subcarrier, or a voice carrier. When the trap circuit configured as described above is inserted in the middle of the power line of the television receiver 1 and the power side terminal 18 and the negative side terminal 19 are connected to the power line, the output terminal 24 is connected as is well known.
The horizontal and vertical synchronization pulses or the color subcarrier or the audio carrier of the television receiver 1 result as output signals.

The RF signal generator 7 may be a group of oscillators corresponding to the required channels, or may be a synthesizer. Further, when the video signal source 17 is a VTR, a built-in television tuner may be used to configure the system as shown in FIG. 3.

FIG. 3a is a schematic diagram showing an embodiment of the RF signal generator, and FIG. 3b is a schematic diagram showing a group of variable resistors for biasing the local oscillation circuit. In the configuration, a local oscillation circuit 25 of a VTR TV tuner is composed of a variable capacitance diode 26 and a coil 27, and when the TV tuner receives each channel, a bias power supply 28a......28f is applied depending on the channel. is applied to the local oscillation circuit 25 via a changeover switch 29 made of, for example, a semiconductor switch. Now, the first
According to the command from the control circuit 6 shown in the figure,
The changeover switch 29 is sequentially switched to cause the local oscillation circuit 25 to oscillate the local oscillation frequency of each channel. The oscillator 30 is configured to oscillate at a frequency approximately equal to the intermediate frequency of the television tuner, and the output of the local oscillation circuit 25 is mixed with the output of the oscillator 30 in a frequency conversion circuit 31, and the output terminal of the frequency conversion circuit 31 is mixed with the output of the oscillator 30. The output appearing at 32 will be equal to the broadcast frequency of the channel. In this way, by adding the oscillator 30 and the frequency conversion circuit 31 to the local oscillation circuit 25 of the TV tuner built in the VTR, the RF frequency shown in FIG.
It can perform the same function as the signal generator 7. In addition, if the tuner built into the VTR is electronic, the bias power supply 28a...28f is built into the broadcasting channel in the area where it is used, so the channel to which the television receiver 1 is tuned is This has the advantage that the search process can be completed in a short time.
In the embodiment shown in FIG. 3a, the bias power supply 28a...28f is used to tune the local oscillation circuit 25, but as shown in FIG. 3b, a variable resistor connected in parallel to the DC power supply 28 28'a…………2
8'f may also be used.

It goes without saying that even in the case of a mechanical tuner, it can be used as part of the RF signal generator 7 if the switching operation is performed using a motor or the like.

FIG. 4 is a schematic diagram showing one embodiment of the control circuit. In the figure, parts corresponding to those in FIG. 1 are given corresponding symbols. In the configuration, when a trigger signal is applied to the input terminal 5a as explained in FIG.
4 starts oscillating. Astable multivibrator 3
Since the output pulse of No. 4 triggers the binary counter 35, the binary counter 35 performs counting by the pulse of the astable multivibrator 34, and the output terminal 37a of the decoder 36...37
j produces sequential outputs. This output terminal 37a...
... 37j causes the RF signal oscillator 7 shown in FIG. 1 to sequentially switch and generate a plurality of channel signals. When the channel signal of the RF signal oscillator 7 matches the channel to which the television receiver 1 is tuned, a signal is applied to the input terminal 5b as explained in FIG.
3 becomes a low level, the oscillation of the astable multivibrator 34 stops, and the output of the binary counter 3 becomes low level.
5 and decoder 36 stop changing.

In each of the above embodiments, the signal from the television receiver 1 and the signal from the test signal source 11 are phase-detected in the phase detector 13.
It goes without saying that the signal from the modulator 8 and the demodulated signal from the modulator 8 may be phase-detected. Furthermore, although the present invention has been described in particular when applied to a VTR, it is also applicable not only to VTRs, but also when connecting television games, video disk players, television cameras, and other television signal sources to television receivers in the form of RF signals. used. It can also be applied when adjusting and measuring a television receiver, or when connecting a measurement signal source.

As described above, the present invention modulates various frequencies corresponding to the channels that can be received by a television receiver with a fixed video signal, and provides this to the television receiver to extract synchronization pulses, thereby automatically Since the video signal can be supplied to the television receiver using a carrier wave that matches the channel to which the television receiver is tuned, it has the effect of simplifying the connection between the signal source and the television receiver.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a tuning detection device according to the present invention. FIG. 2 is an electrical wiring diagram showing one embodiment of the trap circuit. FIG. 3a is a schematic diagram showing an embodiment of an RF signal generator, and FIG. 3b is a schematic diagram showing an embodiment of a bias variable resistor group of a local oscillation circuit. FIG. 4 is a schematic diagram showing one embodiment of the control circuit. In the figures, corresponding parts in each figure are given corresponding symbols, and 1 is a television receiver;
6 is a control circuit, 7 is an RF signal generator, 8
is a modulator, 10 is a test signal source, 11 is a synchronous antenna, 12 is a synchronous separation circuit, 13 is a phase detector,
16 is a level discrimination circuit, 17 is a video signal source, 2
5 is a local oscillation circuit, 28a...28f is a bias power supply, 28'a...28'f is a variable resistor, 30 is an oscillator, 31 is a frequency conversion circuit, 33
34 is an astable multivibrator, 35 is a binary counter, and 36 is a decoder.

Claims (1)

[Scope of Claims] 1. A channel tuning device for video equipment that tunes the output channel of video equipment connected to a television receiver to the channel selected by the television receiver, comprising: a first signal generating means for generating a signal corresponding to a channel available for broadcasting; a second signal generating means for generating a video signal; a modulating means for modulating the signal generated from the signal generating means; and comparing the synchronization or timing signal detected from the television receiver with the synchronization or timing signal of the output of the second signal generation means or the output of the modulation means. and a control means for sequentially switching the signals output from the first signal generation means until both correspond to each other. 2. The channel of the video equipment according to claim 1, wherein the first signal generating means is constituted by an oscillating means that generates a channel signal corresponding to a channel selectable by the television receiver. Tuning device. 3. The first signal generating means is constituted by a television tuner built into the video equipment.
A channel tuning device for video equipment according to claim 1. 4. The television tuner includes: a local oscillation circuit; a bias power supply or variable resistor that sequentially applies different voltages to the local oscillation circuit according to commands from the control means; and oscillates at a frequency approximately equal to the video intermediate frequency. 4. The channel tuning device for video equipment according to claim 3, comprising: an oscillator; and a frequency conversion circuit that mixes the output of the oscillator and the output of the local oscillation circuit. 5. The channel tuning device for video equipment according to claim 1, wherein the period of the synchronization or timing signal of the second signal generating means is shifted from the standard synchronization or timing period of the television receiver. 6. The channel tuning device for video equipment according to claim 1, wherein the synchronization or timing signal of the television receiver is induced and detected by an antenna provided near the television receiver. 7. The channel tuning device for video equipment according to claim 1, wherein the synchronization or timing signal of the television receiver is detected by a trap circuit inserted into the power supply line of the television receiver. 8. The synchronization or timing signal of the second signal generation means is obtained by applying the output signal of the second signal generation means to a synchronization separation circuit or a timing regeneration circuit. Channel tuning device for the video equipment described. 9. The synchronization or timing signal of the output of the modulation means is obtained by demodulating the output signal of the modulation means with a demodulation means and then applying it to a synchronization separation circuit or a timing regeneration circuit. Channel tuning device for the video equipment described. 10 The control means includes: a phase detector that detects the phase of the synchronization or timing signal of the television receiver and the synchronization or timing signal of the second signal generation means or the modulation means; a level discrimination circuit that outputs a signal in response to detection of correspondence between the two; and a switch that sequentially switches the signal generated from the first signal generation means until the level discrimination circuit no longer outputs the signal. A channel tuning device for video equipment according to claim 1, comprising means. 11 The switching means is a J-K switch which is set at the initial stage and reset by a signal output from the level discrimination circuit.
a flip-flop; an astable multivibrator that outputs oscillation pulses in accordance with the set output of the JK flip-flop; a counter that counts the oscillation pulses of the astable multivibrator; and a decoder that decodes the counting output of the counter. A channel tuning device for video equipment according to claim 10.