JPH018021Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a channel selection device for a television receiver that selects a channel based on the output signal of a counter that is reset every time a predetermined number of channels are counted. When trying to preview what is being broadcast on a channel other than the channel, the user can preview a channel other than the one currently being viewed without requiring any troublesome operations.

Conventionally, a channel selection device for a television receiver as shown in FIG. 1 has been proposed in which a channel selection voltage is obtained in accordance with the output signal of a counter, and the reception channel is determined by this channel selection voltage. . That is, in FIG. 1, numeral 1 indicates an electronic tuning section of a television receiver, and this electronic tuning section 1 uses a variable capacitance diode whose capacitance value changes depending on the supplied voltage. In FIG. 1, the electronic tuning section 1 supplies a voltage obtained across a resistor 2 to a variable capacitance diode to determine a reception channel. Further, 3 indicates a push button switch for sequential channel selection, one end of which is connected to a power supply terminal 4 to which a positive DC voltage is supplied, and the other end of which outputs pulses at a fixed period, for example, 0.7 seconds. It is connected to the power supply terminal of the pulse generation circuit 5. The output terminal of this pulse generating circuit 5 is connected to the input terminal of a counter 6. This counter 6 is configured to be reset every time it counts 12 pulses supplied to the input terminal, and the count contents are outputted to the four output terminals as a 4-bit parallel signal consisting of a binary code. It is something that The four output terminals of the counter 6 are connected to the four input terminals of the decoder 7. This decoder 7 has 12 output terminals, and one of the 12 output terminals is grounded by a 4-bit parallel signal supplied to these 4 input terminals. And this decoder 7
One end of a neon lamp 8a, 8b...8l for displaying a reception channel and one end of a variable resistor 9a, 9b...9l for determining a channel selection voltage are connected to the twelve output terminals 7a, 7b...7l, respectively. The other ends of each of these neon lamps 8a, 8b...8l are connected to the power supply terminal 4, and are connected to the variable resistor 9.
The other ends of each of the variable resistors 9a, 9b, . ...10l cathodes are connected respectively, and these diodes 10
The anodes of a, 10b, . . . , 10l are connected in common and connected to the base of an NPN type transistor 12 constituting an emitter follower circuit. Furthermore, the base of this transistor 12 is connected to the power supply terminal 11 via a resistor 13, and the emitter of this transistor 12 is connected to the power supply terminal 11 via a resistor 13.
This collector is grounded via the power supply terminal 11.
It is connected to the.

When selecting a channel using the channel selection device of the television receiver as shown in FIG. 1, the push button switch 3 for sequential channel selection is turned on. At this time, power is supplied to the pulse generation circuit 5 through the push button switch 3, and the pulse generation circuit 5 operates to output pulses at a period of 0.7 seconds. This pulse is supplied to the counter 6, this counter 6 counts this pulse, and the content of this count is supplied as a 4-bit parallel signal to the next stage decoder 7, and in this decoder 7, the pulse is supplied to the counter 6. One predetermined output terminal is grounded each time the output terminal is connected. In this case, output terminals 7a, 7b
. . 7l is grounded, neon lamps 8a, 8b, . For example, the second
When a channel is selected, the push button switch 3 is turned off. At this time, since current flows from the power supply terminal 11 to the variable resistor 9b preset in the second channel, the voltage set in the preset variable resistor 9b is applied to both ends of the resistor 2 via the transistor 12. can be obtained. In this manner, a voltage for channel selection is supplied to the electronic tuning section 1, and a desired selection of, for example, the second channel is made.

In the conventional channel selection device for a television receiver as shown in FIG. 1, a channel can be selected by simply turning on and off the push button switch 3, so that a feather touch type channel selection device can be provided. However, with such a channel selection device, if you want to preview what is being broadcast on a channel other than the channel you are currently watching, you must keep pressing push button switch 3. However, there was the annoyance of having to remember the original channel each time I tried to watch it again.

In view of this, this invention does not require any troublesome operations when trying to preview what is being broadcast on a channel other than the channel you are currently watching, and allows you to easily view what is being broadcast on a channel other than the channel you are currently watching. This allows you to preview the channel.

Hereinafter, an embodiment of the channel selection device for the television receiver of the present invention will be described with reference to FIG. In FIG. 2, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 2, reference numeral 14 indicates a channel one-round feed switch consisting of a push button switch for assisting channel selection.
Connect one end of 4 to power supply terminal 4, and connect the other end to R-
Set terminal S of the S flip-flop 15, reset terminal _R1 of the first T flip-flop 16 and reset terminal of the second T flip-flop 17.
Connect to R ₂ respectively. When the power supply voltage from the power supply terminal 4 is supplied to the set terminal S, this R-S flip-flop 15 is set at the rising time, and a high level signal and a low level signal are obtained from the output terminals Q and 4, respectively, and the reset terminal When a reset signal is input to R, a low level signal and a high level signal are obtained from the output terminals Q and Q, respectively, in synchronization with the rising edge of the signal. Furthermore, when a high level signal as a reset signal is input to the reset terminals _R1 and R2, the first and second T flip-flops 16 and 17 output the output terminals Q1 _{and R2} in synchronization with the rising edge of the signal.
A low level signal is output from _Q2 , and a high level signal is output from output terminal ₁ . Also, trigger terminal T ₁
When a high level signal as a trigger signal is repeatedly input to T2 and _T2 , a high level signal and a low level signal are alternately output from the output terminals _Q1 and _Q2 in synchronization with the rise of each signal.
On the other hand, the output terminal ₁ has a reverse relationship with respect to the output terminal Q ₁ in terms of output of high level signals and low level signals. The output terminal Q of this R-S flip-flop 15 is connected to the input terminal of a pulse generating circuit 18.
When a high level signal, which is a power supply voltage, is input to the input terminal, this pulse generating circuit 18 generates one pulse at a fixed period, for example, 3 seconds, during the period during which the high level signal is input. The output terminal of this pulse generating circuit 18 is connected to the input terminal of the counter 6. Also, counter 6-4
The four output terminals are connected to the four input terminals of the latch circuit 20. This latch circuit 20 stores the input signal immediately before the latch voltage is supplied while the latch voltage is supplied, and outputs the stored signal while the read voltage is supplied. The latch voltage supply terminal of the latch circuit 20 is connected to the output terminal of the R-S flip-flop 15. A signal obtained at the output terminal Q of the R-S flip-flop 15 is supplied to the read voltage supply terminal via a delay circuit composed of a resistor 19 and a capacitor 21. Furthermore, the four output terminals of this latch circuit 20 are connected to exclusive NOR circuits 22, 23, 24, 25, respectively.
Connect to one input terminal of the On the other hand, counter 6
The four output terminals are connected to the other input terminals of these exclusive NOR circuits 22, 23, 24, and 25, respectively. These exclusive NOR circuits 22, 23, 24, and 25 detect whether the input signals match each other, and when the input signals match, these exclusive NOR circuits 2
High level signals are output from output terminals 2, 23, 24, and 25. The output terminals of the exclusive NOR circuits 22, 23, 24, and 25 are respectively connected to four input terminals of an AND circuit 26, and the output terminal of the AND circuit 26 is connected to the trigger terminal T1 of the first T flip-flop _16. Connect to. This first
The output terminal Q ₁ of the T flip-flop 16 is connected to the fixed contact b of the changeover switch 27 and one input terminal of the AND circuit 28, and the output terminal ₁ is connected to the trigger terminal T ₂ of the second T flip-flop 17. . The output terminal Q ₂ of the second T flip-flop 17 is connected to the fixed contact c of the changeover switch 27 and the other input terminal of the AND circuit 28 . These first T flip-flop 16, second T flip-flop 17 and AND circuit 28
is configured to count the number of signals output from the AND circuit 26. Then, the output terminal of the AND circuit 28 is connected to the fixed contact d of the changeover switch 27. The movable contact a of the changeover switch 27 is connected to the reset terminal R of the R-S flip-flop 15. This changeover switch 27 determines how many times the channel is sampled, and fixed contacts b, c, and d correspond to 1st, 2nd, and 3rd turns, respectively.

Assume that the second channel has now been selected in the channel selection device of the television receiver configured as described above. At this time, a case will be described in which the user selects one channel and previews what is being broadcast on a channel other than the second channel that is currently being viewed.

When the channel one-round feed switch 14, which is the start switch, is turned on at current time _t0 , a pulse as shown in FIG. reset terminal _R1 and second
is supplied to the reset terminal _R2 of the T flip-flop 17. Then, the first and second T flip-flops 16 and 17 are reset, and
R-S flip-flop 15 is set. A high level signal, which is the power supply voltage, is supplied from the output terminal Q of the R-S flip-flop 15 to the input terminal of the pulse generation circuit 18 (see FIG. 3B), and a low level signal is output from the output terminal as a latch voltage to the latch circuit. 20 (Fig. 3C)
reference). At this time, the latch circuit 20
The signal obtained at the output terminal of , ie, the signal [0010] for selecting the second channel, is stored.

Also, the output terminal Q of the R-S flip-flop 15
A high-level signal from the pulse generating circuit 18 drives the pulse generating circuit 18, and pulses are supplied to the counter 6 at a period of 3 seconds (see FIG. 3D). 3
A signal delayed by (t ₁ -t ₀ ) as shown in FIG. E is supplied to the read voltage supply terminal of the latch circuit 20, and reading becomes possible. At this time, channels are selected by pulses with a period of 3 seconds outputted from the pulse generating circuit 18, that is, the viewer previews 12 channels in sequence for 3 seconds each.

Then, the signal stored in the latch circuit 20 is transferred to the exclusive NOR circuits 22, 23, 24,
25 (see FIG. 3F), and at this time, exclusive NOR circuits 22, 23, 24, 25 and AND circuit 26 output the output signal of counter 6, which is changing at a cycle of 3 seconds, and the latch circuit 20. The low level signal is continued to be supplied to the trigger terminal _T1 of the first T flip-flop 16 until they match. When the output signal of the counter 6 and the output signal of the latch circuit 20 match, that is,
At time t ₂ , exclusive Noah circuit 2
2, 23, 24, 25 and the outputs of the AND circuit 26 become high level signals (see FIG. 3G). Then, the output terminal Q ₁ of the first T flip-flop 16
and ₁ are high level signals (see Figure 3 H)
and becomes a low level signal. A high level signal from the output terminal _Q1 of the first flip-flop 16 is supplied to the reset terminal R of the R-S flip-flop 15 via the changeover switch 27.
At this time, the R-S flip-flop 15 is reset and outputs a low level signal and a high level signal from its output terminals Q and Q, respectively. By outputting a low level signal from the output terminal Q of the R-S flip-flop 15, the pulse generating circuit 18 is rendered inactive (see FIG. 3D), and the capacitor 21 is discharged (see FIG. 3E). ), the latch circuit 20 stops outputting. Also, R
By outputting a high level signal from the output terminal of the -S flip-flop circuit 15, the latch circuit 20 can freely rewrite its contents without latching. In this way, the channel is selected once at 3 second intervals, and the original channel being viewed is selected again.

When the viewer finds another channel that he/she wishes to view, he/she may select the desired channel by operating the push button switch 3 for channel sequential selection, as in the past.

Furthermore, when trying to test the channel not only once but also twice or three times, the movable contact a of the changeover switch 27 may be switched to the fixed contact c or d, respectively. In this case, fixed contacts c and d
A high level signal is obtained when a high level signal is supplied from the AND circuit 26 twice and three times.

As described above, according to the present invention, when trying to preview what is being broadcast on a channel other than the channel currently being viewed on a television receiver, the channel forward switch 14
By operating , the reception channels automatically change sequentially at predetermined intervals, for example every 3 seconds, and all channels, for example 12 channels, can be previewed in sequence. Therefore, when trying to preview what is being broadcast on a channel other than the one currently being watched, there is no need for the troublesome operation of continuously operating the push button switch 3, etc. as shown in Figure 1.
With a simple operation, you can preview channels other than the one you are currently watching. Further, according to the present invention, a 4-bit signal for selecting a reception channel before operating the channel round feed switch 14 is stored in a latch circuit, and then the output of the latch circuit and the output of the counter are compared. However, when the output of this latch circuit and the output of the counter match, the channel selection operation is stopped, so when you try to watch the channel you were originally watching again, the original channel is memorized and saved. It's very convenient as you don't have to be there.

It goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations may be adopted without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional channel selection device for a television receiver, FIG. 2 is a block diagram showing an embodiment of a channel selection device for a television receiver according to the present invention, and FIG. FIG. 4 is a diagram for explaining the operation of the figure. 6 is a counter, 7 is a decoder, 14 is a channel one-round feed switch, 15 is an R-S flip-flop, 16 and 17 are first and second T flip-flops, 18 is a pulse generation circuit, 19 is a resistor, 20 is a latch circuit, 21 is a capacitor, 2
2, 23, 24 and 25 are exclusive NOR circuits, 26 is an AND circuit, 27 is a changeover switch, and 28 is an AND circuit.

Claims (1)

[Claims for Utility Model Registration] In a channel selection device for a television receiver that determines a channel based on the output of a counter that is reset every time a predetermined number of counts are counted, By operating a feed switch, a pulse generation circuit is operated to supply pulses from the pulse generation circuit to the counter, and a value at the time when the channel one-round feed switch of the counter is operated is stored in a latch circuit; Thereafter, the output of the latch circuit and the output of the counter are compared, and when the output of the latch circuit and the output of the counter match, the operation of the pulse generation circuit is stopped. Channel selection device for digital receiver.