JPS5924224Y2 - television receiver - Google Patents

Description

[Detailed explanation of the idea] This invention relates to television receivers.

Generally, when there is no signal or when the broadcast signal ends, the television receiver will not turn off automatically unless you manually turn it off (off), and when you go out or turn on the television receiver. (On) If you fall asleep with it on, it is extremely dangerous.

Conventionally, it has been considered to use a time switch or the like to turn off the power when the time comes, but this requires external parts and requires presetting of the time switch, which is cumbersome.

This invention was made in view of the above circumstances, and aims to provide a television receiver that can be automatically turned off when a broadcast signal ends to prevent danger.

Hereinafter, one embodiment of this invention will be described in detail with reference to the drawings.

The television receiver according to this invention detects when there is no signal or when the broadcast signal ends using horizontal and vertical synchronizing signals, video signals, audio signals, color burst signals, and combinations thereof, and uses seven detection signals. It is held for a certain period of time using a time constant circuit such as a Nostable multivibrator or counter, and if the broadcast signal does not come again within that period, the television receiver is turned off and placed in a preheat state, and when it is turned on again, it is reset. If you do not do so, you will not be able to turn it on again.

That is, the television receiver according to this invention is constructed as shown in FIG. 1, and includes a tuner 4 consisting of a high frequency amplification circuit 1, a mixer 2, a local oscillator 3, an intermediate frequency amplification circuit 5, a video detection circuit 6, and a video amplification circuit. circuit 7, audio intermediate frequency amplification circuit 8, audio detection circuit 9, audio amplification circuit 10, speaker 11
．． It has a picture tube 12 and a deflection circuit (not shown),
Furthermore, an operation detection circuit 13 is provided on the output side of the tuner 4, and this operation detection circuit 13 is connected to a NOR gate 15 via an OR gate 14.

Further, a signal detection circuit 16 is connected to the output side of the intermediate frequency amplification circuit 5, and this signal detection circuit 16 is connected to the NOR gate 15.

This NOR gate 15 is connected to a set terminal S of a flip-flop circuit 18 via a time constant circuit 17.

On the other hand, the power outlet 19 is connected to a power supply circuit 21 via a power switch 20, and this power supply circuit 21 is connected to an auxiliary power supply having a selectively energizing switch, that is, a preheat switch 22, and a forward diode 23. ,
It is grounded via a reverse diode 24 and a capacitor 25 in series.

The connection point between the diode 23 and the diode 24 is connected to the reset terminal R of the flip-flop circuit 18, and the flip-flop circuit 18 is connected to the preheat switch 22 and the no-signal detection display circuit 2.
6.

Further, the connection point between the diode 24 and the capacitor 25 is grounded via a resistor 27 and a reset switch 28.
It is connected to the.

The movable piece of this reset switch 28 is connected to V via a resistor 29.

C voltage power supply (not shown).

By the way, the main parts of the above device used in a television receiver with mechanical channel selection and a television receiver with electronic channel selection are shown in Figures 2 and 3, respectively. become that way.

In the case of FIG. 2, the input side of the operation detection circuit 13 consisting of the hum amplifier 30 and the integrating circuit 31 is connected to the conductor 32 of the VHF tuning knob and the conductor 33 of the UHF tuning knob, and the output side is connected to the NOR gate 14 and the flip-flop. circuit 1
8 R terminals, respectively.

Also, in the case of Figure 3, an electronic tuning tuner is used,
As shown in a, a box 37 for accommodating potentiometers 34, 35 and 36 for presetting the voltage applied to the variable capacitance diode of the electronic tuning tuner, and a door 38 covering the box are provided on one side of the cabinet 39 of the receiver. ing.

A switch 40 is provided inside the box 37 and operates according to the opening and closing of the door 38.

Note that b is a circuit configuration diagram showing the connection relationship of a.

Now, in the above-mentioned television receiver, during operation, the signal input from the antenna 41 in FIG. The sound enters the audio intermediate frequency amplification circuit 8 via the intermediate frequency amplification circuit 5, is detected by the audio detection circuit 9, is amplified by the audio amplification circuit 10, and is output as sound from the speaker 11.

The output of the intermediate frequency amplification circuit 5 passes through a video detection circuit 6 and a video amplification circuit 7 to display an image on the picture tube 12, and a signal from the video detection circuit 6 enters a synchronous separation circuit (not shown).

Furthermore, the signal from the intermediate frequency amplification circuit 5 is sent to a signal detection circuit 16.
to go into.

This signal detection circuit 16 is a circuit that becomes O when there is no intermediate frequency signal and becomes 1 when there is a signal.

That is, when the output of the signal detection circuit 16 becomes O and a bad condition of the broadcast wave is detected, the flip-flop 18 is set via the NOR gate 15 and the time constant circuit 17 to turn on the preheat switch 22.

As a result, when there is no signal, the biasing force on the deflection circuit and the like is cut off by the switching action of the preheat switch 22, and the filament of the picture tube 12 enters a preheated state.

In this way, when there is no signal, the picture tube 12 is in a preheat state, and the picture tube 12 does not generate a deflected beam and is not in a light emitting state.

However, if the picture tube 12 is always kept in a non-emitting state when there is no signal, the picture tube 12 will be in a non-emitting state unnecessarily even during a transition in channel selection or during reception band adjustment.

In order to cope with this problem, this invention prohibits the picture tube 12 from entering a preheating state during the above-mentioned channel selection transition or reception band adjustment.

That is, the output of the operation detection circuit 13 is input to one input terminal of the OR gate 14, and an AFT (Automatic Frequency Tuning) foot pulse is applied to the other input terminal, which is a signal indicating that a channel selection operation is being performed. appears at the output of OR gate 14.

In other words, A during channel selection transition, reception band adjustment, etc.
When the FT defeat pulse occurs, the above OR gate 14
The output of is 1.

Here, when the output of the OR gate 14 becomes 1, the output of the NOR gate 15 in FIG. 1 always becomes 0.

As a result, the output of the NOR gate 15 becomes 0 regardless of the determination result of the presence or absence of a broadcast signal by the signal detection circuit 16, and the flip-flop 18 is prohibited from being set unnecessarily.

Further, in cases other than during channel selection transition, reception band adjustment, etc., the operation detection circuit 13 and the AFT defeat pulse are not applied to the OR gate 14, and the output of the OR gate 14 becomes O.

Therefore, the broadcast ends during reception and the signal detection circuit 16
When the output of the gate becomes 0, the output of the NOR gate 15 becomes 1, the flip-flop 18 is set, and the picture tube 12 enters a reheating state.

In this way, control is performed to prevent the picture tube 12 from being put into a preheated state unnecessarily.

As mentioned above, as shown in FIG.
After being amplified, the signal is put into an integrating circuit 31, converted to direct current, passed through an OR gate 14, and then enters a NOR gate 15.

Therefore, this circuit does not operate when the tuning knob is operated.

On the other hand, an embodiment of a receiver using an electronic tuning tuner is shown in FIGS. 3a and 3b as described above. There is a box 37 to accommodate and a door 38.

Since it is necessary to stop the operation of the signal detection circuit 16 while the tuning voltage is being adjusted, when the door 38 is opened as shown in FIG. 3A, the switch 40 inside the box 37 is opened.

Then, as shown in Figure 3, the input of the OR gate 14 is 1.
Therefore, the output becomes l, and the operation of the signal detection circuit 16 is stopped.

When switching channels, this is detected by a detector (not shown) and a defeat pulse 1 is manually applied to the OR gate 14 to stop the operation of the signal detection circuit 16.

When this signal detection circuit 16 operates and enters the preheat state, by resetting the flip-flop circuit 18 with the reset switch 28 or by touching the tuning knob using the circuit shown in FIG. You can turn on the receiver automatically.

Note that this automatic reset circuit can be easily realized in a touch channel selection receiver by using an input circuit signal.

When the all-off switch is turned off to turn off the receiver, and then the all-off switch is turned on, a reset signal for the flip-flop circuit 18 is generated from the power supply circuit 21, and the diode 2
Added through 3.

The television receiver of this invention is constructed as described above and illustrated, and detects the presence or absence of a signal when there is no signal during reception or when the broadcast signal ends, and after a certain period of time, puts the receiver into a preheat state. Even if you go out or fall asleep with the receiver plugged in, it will automatically turn off (preheat state), which is very useful for preventing danger.

In the above embodiment, the output signal of the intermediate frequency amplifier circuit 5 is used as the input signal of the signal detection circuit, but it may be a horizontal or vertical synchronizing signal, an audio signal, a color burst signal, or a combination thereof.

As explained above, according to this invention, a television receiver with great practical value can be provided.

[Brief explanation of the drawing]

Figure 1 is a circuit configuration diagram showing a television receiver according to an embodiment of this invention, and Figure 2 is a circuit diagram showing the main parts when this invention is used in a mechanical channel selection television receiver. , FIGS. 3a and 3l) are a perspective view and a circuit configuration diagram showing the main parts when this invention is used in a television receiver with electronic channel selection. 4...Tuner, 5...Intermediate frequency amplification circuit, 13...Operation detection circuit, 14...
・Or Gate, 15...Noah Gate, 16...
... Signal detection circuit, 17 ... Time constant circuit,
18...Flip-flop circuit, 21...
...Power supply circuit, 22...Preheat switch,
26... No signal detection display circuit, 28...
・Reset switch.

Claims (1)

[Scope of claim for utility model registration] A signal detection circuit that receives the output of a video intermediate frequency amplification circuit and outputs a control signal depending on the presence or absence of broadcast waves, and an operation that outputs a signal indicating that a channel selection operation is in progress. a detection circuit; and a flip-flop that receives the output of the operation detection circuit and the output of the signal detection circuit as input, and is set by an output signal from the signal detection circuit indicating that there is no broadcast wave at times other than when a channel selection operation is performed. , a preheat switch that operates this flip-flop and stops the operation of the main power circuit that energizes the entire television receiver, and energizes only the sub power circuit that preheats the picture tube; and energizes the main power circuit. and a reset means for resetting the flip-flop when the television receiver is energized, and when the broadcast wave is no longer detected due to the end of broadcasting, etc., the operation of the main power circuit is automatically stopped and the sub power circuit is activated. A television receiver characterized by bringing a picture tube into a preheated state.