JPS6232866B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video tape recorder (hereinafter simply referred to as
This invention relates to a television receiver with a built-in VTR, which allows broadcast images of a selected channel to be displayed immediately by performing a channel selection operation even when a television image is being reproduced from a VTR (referred to as a VTR).

In recent years, the development of low-cost VTRs has progressed, and so-called home VTRs have become rapidly popular.

Most of the VTRs used in ordinary homes are used to record and play back television broadcasts, and are therefore often used in combination with a television receiver (hereinafter simply referred to as a television).
For this reason, TVs with built-in VTRs have begun to appear on the market.

A particularly important requirement for household electrical equipment is that it be easy to operate. Unless the overall operation of a device is simplified, it has little meaning for general household use.

Therefore, as a television incorporating a VTR, for example, as shown in FIG. 1, there is a known television equipped with a microcomputer (hereinafter referred to as microcomputer) for control.

In FIG. 1, 1 is a channel selection switch unit having a plurality of self-restoring channel selection switches such as pushbutton switches, 2 is a microcomputer, and 3
a, 3b are the channel selection sections on the TV side and VTR side.
4a, 4b are tuning voltage amplifier circuits, 5a, 5b are band switching output circuits, 6a, 6
b is a default amplifier circuit, 7a and 7b are channel selection preset memories, 8a and 8b are electronic tuning tuners including IF amplification and a video detector, 9 is a receiving antenna, 10 is a distributor, 11 is a video signal switching circuit, 1
2 is a video amplification circuit, 13 is a cathode ray tube, 14 is
VTR 15 is a shutoff circuit.

Next, its operation will be explained.

Now, when a push button switch corresponding to a necessary channel of the channel selection switch section 1 is pressed in order to receive a television broadcast, a signal corresponding to that switch is given to the microcomputer 2.

The microcomputer 2 determines the channel based on the input signal, and supplies a channel selection reset pulse signal and a channel selection order feed pulse signal to the channel selection sections 3a and 3b. Each channel selection unit 3a, 3b is first reset from the current tuning position to a reference starting position by a tuning reset pulse signal, and then by a tuning order feed pulse signal, the tuning positions are changed by the number corresponding to the channels to be selected. The channels are sequentially fed and set at the tuning position corresponding to that channel.

When the required tuning position is set, the tuning voltage and reception band information corresponding to the tuning position are read out from the preset memories 7a, 7b, and the tuning voltage is changed to the tuning voltage via the tuning voltage amplification circuits 4a, 4b.
Band switching output signals are then transmitted to the electronic tuning tuner 8 via the band switching output circuits 5a and 5b.
a, 8b.

The electronic tuning tuners 8a and 8b tune to a predetermined channel using the applied tuning voltage and band switching output signal, and select the broadcast of the selected channel from the received signal supplied from the antenna 9 via the distributor 10. , outputs the detected video signal after IF amplification.

At the same time, each tuning section 3a, 3b gives a default pulse signal to the electronic tuning tuner 8a, 8b as the tuning position changes.
A default pulse signal is supplied to b and the tuner's AFS voltage (automatic frequency correction voltage) is fixed during channel switching operation to prevent blurring of the image.

The video signal output from the electronic tuner 8a is supplied to a video signal switching circuit 11, and then supplied to a cathode ray tube 13 via a video amplification circuit 12 to reproduce a television image.

Further, the video signal output from the electronic tuner 8b is supplied to the VTR 14 and recorded.

When the VTR 14 is in the playback operation state, it is configured to generate a playback status signal representing the playback operation state, and to supply this signal to the control input of the video signal switching circuit 11 and one input of the shut-off circuit 15. The video signal reproduced during operation is supplied to the video signal input of the video signal switching circuit 11. Therefore, when the VTR 14 is in the playback state, a playback state signal is applied to the control input of the switching circuit 11, and this switching circuit 11 transfers the video signal played from the VTR 14 from the video amplifier circuit 12 to the cathode ray tube. 13.

Therefore, while the VTR 14 is in playback operation, even if a channel is selected by pressing the button on the channel selection switch section 1, the broadcast of the selected channel is not received on the cathode ray tube 13.

Therefore, the tuning reset pulse signal generated from the microcomputer 2 when selecting a channel is supplied to the other input of the shutoff circuit 15.

Now, the input of the shutoff circuit 15 is
A playback status signal from the VTR 14 and a tuning reset pulse signal from the microcomputer 2 are added, and when the tuning switch is operated while the VTR 14 is in playback mode, a shutoff signal is generated from the shutoff circuit 15, and this signal will be supplied to the shut-off input of the VTR 14.

When the VTR 14 receives a shut-off signal during a playback operation, the playback operation is immediately canceled, so naturally the playback status signal also disappears.
Therefore, the video signal switching circuit 11 performs a switching operation as the reproduction status signal applied to its control input disappears, and supplies the video signal from the electronically tuned tuner 8a from the amplifier circuit 12 to the cathode ray tube 13. Switch.

Therefore, even when the VTR 14 is in playback operation and the reproduced video is displayed as an image on the cathode ray tube 13, by pressing the switch on the channel selection switch section 1, the selected channel is automatically displayed on the cathode ray tube 13. broadcasts will be played back as images, making it possible to easily and simply operate a TV with a built-in VTR, and to reduce malfunctions.

However, such a TV with a built-in VTR is provided with a microcomputer for control, which is disadvantageous in terms of cost. This microcomputer usually requires a 4-bit one, which inevitably increases costs.

Therefore, considering cost issues, it is conceivable to configure the system so that control is performed without using a microcomputer. However, in that case,
Since there is no need to reset the tuning position when operating the tuning switch, a tuning reset pulse signal cannot be obtained and a shut-off signal cannot be generated.

It is also possible to obtain the shutoff signal from the default pulse signal generated during tuning, but if the channel selected by the tuning switch is the same as the previously selected channel, the tuning section will not be able to select the shutoff signal. Since the position does not change, no default pulse signal is generated,
Shutoff signal cannot be obtained.

Therefore, in the past, the use of a microcomputer was indispensable, which was a major factor in increasing costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a VTR-embedded television channel selection device that eliminates the drawbacks of the prior art described above and can completely shut off the VTR in conjunction with channel selection operations without using a microcomputer. be.

In order to achieve this object, the present invention is characterized in that, when the VTR starts playing, the tuning position of the VTR-side tuning section is always moved to a position that does not correspond to any of the tuning switches. shall be.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram of a channel selection device according to an embodiment of the present invention, in which the same or equivalent parts as in the conventional example of FIG. 1 are given the same numbers.

In FIG. 2, 17a and 17b are tuning sections, 18a and 18b are tuning voltage output circuits, 19 is a tuning circuit during playback, and 20 is a push button switch that closes only when operated, and restores when released. This is a channel selection switch section that is provided with a plurality of self-restoring type switches that open depending on the channel.

Channel selection sections 17a, 17 on the TV side and VTR side
b is (1) clock oscillation circuit, (2) channel pulse synthesis circuit, (3) channel skip circuit, (4) 4-bit up-down counter circuit, (5) 4-bit/16-line decoder circuit, (6) )16-line inverter buffer circuit, etc., and a tuning voltage output circuit 18a on the TV side and VTR side.
Reference numeral 18b is of a preset type, and the channel selection switch section 20 has two push button switches for each channel selection.
It has a contact configuration, with one circuit corresponding to the TV side and the other circuit corresponding to the VTR side.

Next, its operation will be explained.

When one of the pushbutton switches of the channel selection switch section 20 is pressed, a signal representing the corresponding channel is given to the channel selection sections 17a and 17b,
The tuning position for the selected channel is scanned and set. As a result, the channel selection operation using the pushbutton switch of the selection switch section 20 only takes a short time, and is a so-called touch switching operation. Note that this also applies to the conventional example shown in FIG.

When set to the tuning position, band switching output circuits 5a, 5b and tuning voltage output circuits 18a, 1
The band switching signal and tuning voltage are output from 8b respectively.
The video signal is applied to the electronic tuning tuners 8a, 8b including IF amplification and detection circuits, and is tuned to the broadcast signal of the selected channel.As explained in FIG.
It is output from b.

Also, at this time, the default pulse signal is supplied from the default amplifier circuits 6a, 6b to the respective electronic tuning tuners 8a, 8b, and the default operation is carried out in the same way as in the case of FIG.

Now, the video signal switching circuit 11 supplies the video signal from the tuner 8a to the video amplification circuit 12 when the reproduction status signal from the VTR 14 is not applied, and reproduces the video signal on the cathode ray tube 13 as a television image. During operation, switching is performed by the reproduction status signal generated thereby, and the reproduced video signal from the VTR 14 is supplied to the amplifier circuit 12, and the resulting image is projected from the cathode ray tube 13.

Therefore, even if the channel selection switch section 20 is operated while the VTR 14 is in playback mode, the broadcast image of the selected channel will not be displayed on the cathode ray tube 13.

Therefore, the default pulse signal from the default amplifier circuit 6b on the VTR side is sent to the shutter-off circuit 1.
5 and the reproduction status signal from the VTR 14 to generate a shut-off signal, and this signal is supplied to the shut-off input of the VTR 14.

Therefore, even when the VTR 14 is in playback mode and the subsequent image is being projected from the cathode ray tube 13, if you press the pushbutton switch of the channel selection switch section 20 to select any channel, the output from the default amplification circuit 6b is Defeat pulse signal and
A shut-off signal is generated from the shut-off circuit 15 in response to a playback status signal from the VTR 14 itself,
The VTR 14 is released from the playback state, and the switching circuit 1
1, the output from the tuner 8a is displayed on the cathode ray tube 13, which simplifies the operation.

However, as already explained, since the channel selection units 17a and 17b are directly controlled by the channel selection switch unit 20 without using a microcomputer, the channel to be selected may happen to be the same as the previously selected channel. When it gets hot, the channel selection section 17
The states of a and 17b do not change. In other words, it remains at the same tuning position as before, and the same tuning voltage and band switching signal are applied to the electronically tuned tuner 8.
Of course, the default signal is not generated by simply continuing to be supplied to a and 8b.

Therefore, when the VTR 14 is used as a reproduction status signal and the reproduced video is displayed on the cathode ray tube 13, when one of the pushbutton switches of the channel selection switch section 20 is pressed to select a channel, many In this case, the image being projected from the cathode ray tube 13 is automatically switched from the one played from the VTR 14 to the image of the selected television broadcast, but the selected channel happened to have been selected previously. If the channels are the same, the images reproduced from the VTR 14 will continue to be projected from the cathode ray tube 13, and the images will not be switched.

Therefore, in this embodiment, a playback channel selection circuit 19 is provided, a playback status signal from the VTR 14 is supplied to this circuit 19, and whenever the VTR 14 enters the playback state, the playback channel selection circuit 19 is activated for a certain period of time. make it work only.

The playback tuning circuit 19 is a tuning section 17b on the VTR side.
A signal similar to the signal from the tuning switch section 20 is applied to the channel selection section 17b, and the tuning section 17b is set at a tuning position corresponding to the input from the circuit 19.

Therefore, once the VTR 14 enters the playback operation, the playback channel selection circuit 19 operates for a certain period of time according to the playback status signal from the VTR 14, and the channel selection section 1
7b to start its tuning position selection operation. At this time, since the input from the circuit 19 is at a different tuning position from the input from any switch in the tuning switch section 20, the tuning section 17b is always at a different tuning position regardless of the state of channel selection before that point. Start operation.

When the tuning section 17b reaches the tuning position corresponding to the input from the reproduction tuning circuit 19, it remains set there. Of course, the band switching signal and tuning voltage applied to the electronic tuning tuner 8b at this time may be in any form.
This is because VTR14 is in playback mode,
This is because there is no problem no matter what the output of tuner 8b on the VTR side is.

Therefore, the image from the VTR 14 is transferred to the cathode ray tube 1.
3, if one of the pushbutton switches in the channel selection switch section 20 is pressed during playback, even if the channel corresponding to the pressed switch is the same as the channel that was selected before the VTR 14 was started playing. , only the channel selection unit 17b on the VTR side necessarily starts the channel selection position selection operation. Because VTR1
4 is in playback operation, the tuning position of the tuning section 17b is selected and set at the position corresponding to the input of the tuning circuit 19 during playback, and this position is set to the position corresponding to the input of the tuning circuit 19 during playback. This is because it is not compatible with

When the tuning section 17b operates, a default signal is generated, and therefore a shut-off signal is given to the VTR 14 from the shut-off circuit 15 and the VTR 14 is turned on.
The playback operation is canceled. Then, the reproduction status signal disappears and the video signal switching circuit 11 displays the video output from the electronic tuner 8a from the cathode ray tube 13.In the end, according to this embodiment, by selecting the channel, The reproduced image from the VTR 14 is necessarily automatically switched to the broadcast image of the selected channel, and there is no need to use a microcomputer, so there is no cost increase.

Next, a specific example of the tuning section 17b and its surrounding parts in this embodiment is shown in FIG.

In FIG. 3, the same or equivalent parts as in FIGS. 1 and 2 are given the same numbers.

In FIG. 3, 20b is the channel selection switch section 20.
The VTR side part 201b is a switch corresponding to one of the channels. 21 is a clock oscillation circuit, 22 is a pulse synthesis circuit, 23 is a default pulse generation circuit, 24 is a 4-bit binary up-down counter, and 25 is a 4-bit
16 line decoder, 26 is a 16 line inverter buffer, 28 is a tuning voltage power supply terminal, 29 is a tuning voltage output terminal, 30 is a variable resistor for tuning voltage presetting, 35 is a default signal output terminal, 36 is a tuning circuit for playback Transistor 37 constituting 19
is also a capacitor for providing a time constant, 3
8 and 39 are also resistors, 40 is an AND gate constituting the shut-off circuit 15, 41 is its output terminal, and 42 and 43 are resistors and capacitors for providing a time constant. Note that 31 to 34 are terminals of each part.

Next, its operation will be explained. First, the parts 21 to 26 that make up the tuning section 17b are integrated circuits, and in a steady state, the ground potential "0" appears in only one of the 16 outputs of the buffer 26, and the remaining 15 outputs A high level potential ``1'' appears at .

Also, among the 16 outputs of the 26 buffers, the 12 outputs from the top terminal 32 downward are connected to each switch of the channel selection switch section 20b, for example, the switch 201b, and are connected to each channel. It has become compatible. The 13th output 33 from the top is connected to the tuning circuit 19 during playback,
It does not correspond to any switch in the channel selection switch section 20b, that is, to any channel.

Further, when the input to the terminal 31 becomes "1", the clock oscillation circuit 21 sends the clock pulse to the counter 24 via the pulse synthesis circuit 22 and also supplies it to the default pulse generation circuit 23, whereby the counter 24 receives the clock pulse. , the output data is given to the decoder 25, and "0" signals are sequentially generated at the 16 outputs. As a result, Batsuhua 26
Only one of the 16 outputs of the buffer 26 becomes "0", and the position of this "0" output sequentially moves at a predetermined speed in a predetermined direction. The output will be sequentially scanned by the "0" signal.

Now, assume that one of the switches in the channel selection switch section 20b, for example, the switch 201b, is pressed and closed.

At this time, if the output 32 of the buffer 26 is not in the "0" state but in the "1" state, this signal "1" is applied to the terminal 31 through the switch 201b. As a result, clock pulses begin to be supplied from the oscillation circuit 21 to the counter 24, and the "0" state at the output of the buffer 26 is sequentially shifted. At the same time, a default signal is sent from the terminal 34.

The "0" state at the output of the buffer 26 changes one after another, and eventually when the output 32 becomes "0", the terminal 31 also becomes "0" and the generation of clock pulses stops. Therefore, the output state of the buffer 26 is such that the output 32 is "0" and all the remaining outputs remain "1".

Therefore, the voltage from the terminal 28 becomes the voltage preset by the variable resistor 30 and appears at the terminal 29, and this becomes the tuning voltage and is applied to the electronic tuning tuner 8.
b, and channel tuning will be performed.

In this way, scanning is performed so that the output of the buffer 26 connected to that pushbutton switch becomes "0" no matter which pushbutton switch of the channel selection switch section 20b is pressed. The position is set.

At this time, since the period of the clock pulse from the clock oscillation circuit 21 is extremely short, the time required for one scan of the 16 outputs of the buffer 26 is also extremely short, and can be said to be almost instantaneous.
Therefore, it is only necessary to press the push button switch of the channel selection switch section 20b for a short time, and only a light touch is required.

The reason why such a configuration is adopted for the channel selection section 17b (and 17a) is as described above.
This is to enable so-called touch channel selection.

By the way, unlike the above case, the buffer 26
Suppose that the output 32 of is "0".

In this case, no change will occur even if the push button switch 201b is pressed. In other words, switch 2
Even if 01b is closed, the output 32 is "0" and the terminal 31
also remains at "0" and does not change, so no clock pulse is generated.

Therefore, in this case, no default signal is generated at the terminal 34, and even if the VTR 14 is in playback operation, no image switching is performed.

However, when the VTR 14 generates a playback status signal at its terminal 44, this playback status signal is passed through the resistor 3.
8 and the reproducing channel selection circuit 19 via the capacitor 37.
The signal is supplied to the transistor 36, and the transistor 36 is made conductive for a predetermined period of time.

As a result, among the outputs of the buffer 26, the signal "1" appearing at the output 33 corresponding to the tuning circuit 19 during reproduction is given to the terminal 31 through the transistor 36, so that the tuning section 17b is placed at the tuning position. , and stops at the position where the output 33 of the buffer 26 becomes "0".

In other words, when the VTR 14 starts playing, the tuning section 17b immediately reaches the position where the output 33 of the buffer 26 becomes "0" regardless of the tuning state up to that point.
The tuning position scanning operation is performed, and the output 33 of the buffer 26 is always "0" while the VTR 14 is in playback operation.
It is made to be in a state of being.

Therefore, if the channel selection operation is performed by pressing the pushbutton switch of the channel selection switch section 20b while the VTR 14 is in playback mode, a clock pulse will always be generated from the clock oscillation circuit 21 even if the channel selection is the same as before. is generated and terminal 3
4, a default signal is necessarily generated, and this signal is supplied from the default amplifier circuit 6b to one input of the AND gate 40 of the shut-off circuit 15, and is used as a shut-off signal together with the playback status signal from the terminal 44 of the VTR 14. Then, a shut-off signal is applied from the output terminal 41 to the shut-off input terminal 45 of the VTR 14, and the reproduction operation is canceled.

Although not shown in the example of Fig. 3,
The playback status signal from the terminal 44 of the VTR 14 is
Needless to say, it is also supplied to the control input of the video signal switching circuit 11 shown in the figure.

As explained above, according to the present invention, a VTR shut-off signal can always be reliably generated without using a microcomputer, so compared to TVs with built-in VTRs that are easy to operate and have less risk of erroneous operation. can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a channel selection device in a television receiver with a built-in video tape recorder using a microcomputer for control, and FIG. 2 is a block diagram showing an example of a channel selection device with a built-in video tape recorder according to an embodiment of the present invention. FIG. 3 is a wiring diagram showing a specific circuit example of the main part of the channel selection device shown in FIG. 2. 5a, 5b...Band switching output circuit, 6a, 6
b... Defeat amplifier circuit, 8a, 8b... Electronic tuning tuner (including IF amplification and detection circuit), 11
...Video signal switching circuit, 13...Cathode ray tube, 1
4... Video tape recorder, 15... Shut-off circuit, 17a, 17b... Tuning section, 18a,
18b... Tuning voltage amplification circuit, 19... Tuning circuit during reproduction, 20... Tuning switching section.

Claims (1)

[Claims] 1. A channel selection switch section consisting of a plurality of self-restoring switches corresponding to each channel, and a channel selection operation for the plurality of switches in this switch section starts the operation of sequentially scanning the output of this switch, and a tuning voltage selection section configured to stop this operation upon reaching the output, generate a tuning voltage corresponding to the switch, and generate a default signal during the operation, and its state during the television signal reproduction operation; a video tape recorder configured to generate a playback status signal representing a playback status signal and to stop the playback operation by a shutoff signal; and means for generating the shutoff signal based on the default signal and the playback status signal. In a television receiver with a built-in tape recorder, a portion of the output scanned by the channel selection voltage selection section is provided with an output that is not connected to any of the outputs of the switches of the selection switch section; The scanning operation is configured to be started also by the playback status signal, and while the video tape recorder is in the playback operation, the scanning operation of the channel selection voltage selection section is always started at an output not connected to the output of the switch. A channel selection device for a television receiver with a built-in tape recorder, characterized in that the channel selection device is configured to be stopped.