JPS5850673Y2 - television receiver - Google Patents

Description

[Detailed description of the invention] The present invention relates to a television receiver in which a television image and a waveform related to an audio signal can be switched and viewed on the same cathode ray tube. This is to eliminate blurring of the waveform display related to the audio signal due to noise at certain times.

An example of a television receiver in which a television image and a waveform related to an audio signal can be switched and viewed on a cathode ray tube will be described below with reference to the drawings.

In Fig. 1, 1 indicates an antenna, and this antenna 1
The television broadcast signal obtained in the above is supplied to the tuner device 2, and the output signal of the tuner device 2 is supplied to the input side of the video detection circuit 4 via the video intermediate frequency amplifier 3. The output signal is supplied to the movable contact 5a of the switch 5, and the output signal of the video detection circuit 4 is supplied to the input side of the synchronization signal separation circuit 6.

The first fixed contact 5b and the second fixed contact 5c of this switch 5 are connected to each other, this connection point is connected to the input side of the video amplification circuit 7, and the third fixed contact of this switch 5 is connected to the input side of the video amplification circuit 7. Ground 5d.

The output signal of the video amplification circuit 7 is supplied to the cathode of the cathode ray tube 8.

Also, the brightness control terminal of this video amplification circuit T is connected to the first and second fixed contacts 9b and 9c of the brightness switch 9, respectively, and connected to the third fixed contact 9d via a resistor 10, The movable contact 9a of this brightness switch 9 is grounded.

The brightness of the cathode ray tube 8 is adjusted by the brightness switch 9,
This is to make it easier to see the waveform of the audio signal.

Further, the horizontal synchronizing signal obtained at one output terminal of the synchronizing signal separation circuit 6 is supplied to one input terminal of the horizontal automatic frequency control circuit 11, and the control signal obtained at the output side of the horizontal automatic frequency control circuit 11 is applied to the horizontal The output signal is supplied to the oscillation frequency control terminal of the oscillator 12, the output signal obtained at the output terminal of the horizontal oscillator 12 is supplied to the horizontal deflection output circuit 13, and the horizontal deflection signal obtained at the output side of the horizontal deflection output circuit 13 is supplied to the cathode ray. The horizontal frequency signal obtained from the horizontal deflection output circuit 13 is supplied to the other input terminal of the horizontal automatic frequency control circuit 11.

As is well known, in this horizontal automatic frequency control circuit 11, the horizontal synchronization signal obtained at the output side of the synchronization signal separation circuit 6 and the horizontal frequency signal obtained at the horizontal deflection output circuit 13 are compared, and the error signal is A corresponding control signal is generated, and the oscillation frequency of the horizontal oscillator 12 is controlled by this control signal.

Further, the vertical synchronizing signal obtained at the other output terminal of the synchronizing signal separation circuit 6 is supplied to the vertical oscillator 14 as a synchronizing signal, and the output signal of this vertical oscillator 14 is supplied to the vertical deflection output circuit 15. The vertical deflection signal obtained at the output side of 15 is supplied to the deflection coil 8a of the cathode ray tube 8.

Further, the output signal of the tuner device 2 is supplied to one input terminal of the audio signal mixing circuit 16 for obtaining an audio signal, and the output signal of the audio signal local oscillator 17 is supplied to the other input terminal of the audio signal mixing circuit 16. An audio signal output that supplies the output signal of the mixing circuit 16 to the input terminal, supplies the output signal of the mixing circuit 16 to the input side of the audio detection circuit 18, and supplies the output signal of the audio detection circuit 18 to the speaker via the muting circuit 19. Terminal 20 is supplied.

In this case, when the movable contact 21a of the changeover switch 21 is connected to one of the fixed contacts 21b, when the output signal of this audio detection circuit 18 disappears for a predetermined time, and when the output signal of this audio detection circuit 18 is below a predetermined level, The muting circuit 19 operates when the signal continues for a predetermined period of time and mutes the output signal.

Also, when the movable contact 21a of this changeover switch 21 is connected to the other fixed contact a21c, this muting circuit 1
9 is designed not to perform a muting operation.

Further, 22L and 22R indicate recording signal input terminals for left and right channels, respectively, and secondary recording signal input terminals 22L and 2
The left and right channel recording signals supplied to 2R are output to left and right channel recording signal output terminals 23L and 23, respectively.
The left and right channel recording signals are supplied to fixed contacts 24b and 25b of switchers 24 and 25, respectively, and 26L and 26R are stereo signals from a tape recorder, for example. shows left and right channel signal input terminals to which left and right channel signals are supplied, and left and right channel signals which supply left and right channel signals supplied to secondary input terminals 26L and 26R, respectively, to the loudspeakers, respectively. In addition to supplying the left and right channel signals to output terminals 27L and 27R, respectively,
c and 25c, respectively.

In this case, each movable contact 24 of this switch 24 and 25
a and 25a are linked.

That is, when the movable contact 24a is connected to one fixed contact 24b, the movable contact 25a is connected to one fixed contact 25b.
When the movable contact 24a is connected to the other fixed contact 24c, the movable contact 25a is connected to the other fixed contact 25c.

Further, the movable contact 24a of the switch 24 is supplied to one input terminal of the mixing circuit 30L via a resistor 28L having a relatively high resistance value and a gain adjuster 29L.

This mixing circuit 30L generates an audio signal to display the waveform supplied to one of the input terminals and a sawtooth wave signal synchronized with the horizontal pulse obtained at the output side of the horizontal deflection output circuit 13. The sawtooth wave signal from the sawtooth wave signal generation circuit 31 is superimposed.

31a is a horizontal pulse input terminal to which the horizontal pulse obtained at the output side of the horizontal deflection output circuit 13 is supplied.

The output side of this mixing circuit 30L is grounded via a variable resistor 32L for adjusting the display position, and the mixing circuit 30L is
The output side of L is connected to the input side of a Schmitt trigger circuit 33L constituting a clipper circuit, and the signal obtained at the output side of this Schmitt trigger circuit 33L is transferred to a differentiating circuit 34.
The signal is supplied to the input side of the video amplification circuit 7 via L and the addition circuit 35.

On the output side of the differentiating circuit 34L, one display pulse signal, for example, phase modulated in the positive direction, is obtained in one horizontal period.

Furthermore, the movable contact 25a of the switch 25 is connected to one fixed contact 36b of the multipath signal display switch 36 via a resistor 28R with a relatively high resistance value, and is also connected to the multipath terminal of the FM radio receiver. multipath signal input terminal 37
is connected to the other fixed contact 36c of this switch 36, and the movable contact 36a of this multipath signal display switch 36 is connected to the third fixed contact 38d of the display content switch 36.
Also, the second fixed contact 38c of this display content switcher 38 is connected to the audio signal output terminal 20, and this second fixed contact 38c is connected to the audio signal output terminal 20.
The audio signal of the television broadcast signal is supplied to the terminal c, and the first fixed contact 38b of the display content switching device 38 is set in an electrically floating state.

The movable contact 38a of the display content switch 38 is supplied to one input terminal of the mixing circuit 30R via the gain adjuster 29R, and a sawtooth wave signal synchronized with the horizontal pulse from the sawtooth signal generation circuit 31 is supplied. The signal is supplied to the other input terminal of the mixing circuit 30R, and the signal whose waveform is to be displayed is superimposed on the sawtooth wave signal synchronized with the horizontal pulse in the mixing circuit 30R.

In this case, the output side of the circuit 30R is grounded through a series circuit of a variable resistor 32R for adjusting the display position and a resistor 39 for adjusting the display position.
9 is connected to the second fixed contact 40c of the display position adjustment switch 40, and the first and third . Fixed contact 40
b and 40d are electrically floating, and the movable contact 40a of this switch 40 is grounded.

In addition, the output side of this mixing circuit 30R is connected to the input end of a Schmitt trigger circuit 33R constituting a clipper circuit,
The signal obtained at the output side of the Schmitt trigger circuit 33R is supplied to the input side of the video amplification circuit 7 via a differentiator circuit 34R and an adder circuit 35.

In this case, the output side of the differentiating circuit 34R has a differentiating circuit 34L.
Similarly to the output side, one display pulse signal, for example, which is phase modulated in the positive direction, is obtained in the horizontal period.

In this case, a display signal such as an audio signal supplied to the input sides of the gain adjusters 29L and 29R is supplied to one input side of the mixing circuits 30L and 30R, and the sawtooth wave generation circuit 31
mixes a sawtooth signal synchronized with the horizontal pulse of
This is supplied to Schmitt trigger circuits 33L and 33R, which changes the phase of the clipping point in proportion to the amplitude of the audio signal, that is, phase-modulates it, and supplies this phase-modulated waveform to differentiating circuits 34L and 34R. Then, one phase-modulated positive pulse signal obtained at the output side of the differentiating circuits 34L and 34H in one horizontal period is supplied to the input side of the video amplification circuit 7 via the addition circuit 35, and the cathode ray A vertical luminance varying horizontally is displayed on the tube 8.

Further, the output side of the differentiating circuit 34L is connected to the second fixed contact 42c of the switch 42 via a diode 41, and the output side of each of the differentiating circuits 34L and 34R is connected to the switch 42 via diodes 43L and 43R. The first fixed contact 42 of
b, and this third fixed contact 42d is connected to a power terminal B to which a positive DC voltage is supplied via a stereo display lamp 44, and the movable contact 42a of this switch 42 is grounded.

In this case, the movable contacts 5a, 9a, 38a, 40a and 42a of the switching devices 5, 9, 38, 40 and 42 are made to interlock with each other.

That is, when displaying only a television image on the screen of the cathode ray tube 8, the second movable contacts 5a, 9a, 38a,
40a and 42a are the respective first fixed contacts 5b and 9
b.

38b, 40b and 42b, respectively.

At this time, the output sides of the differentiating circuits 34L and 34R are grounded via diodes 43L and 43R, respectively, so that the output signals of the differentiating circuits 34L and 34R are not supplied to the video amplification circuit γ.

The output signal of the video detection circuit 4 is supplied to the video amplification circuit 7 via the switch 5, and the video amplification circuit 7 is made to operate normally by the switch 9.

Further, when simultaneously displaying a television image and a waveform Sa based on the audio signal of this television broadcast on the screen of the cathode ray tube 8, as shown in FIG. 2A, the second movable contact 5a,
9a, 38a, 40a and 42a are respectively second fixed contacts 5c, 9c and 38c.

40c and 42c, respectively.

At this time, the output signal of the video detection circuit 4 is supplied to the video amplification circuit 7 via the switch 5, and the video amplification circuit 7 operates normally depending on the switch 9. The audio signal of the broadcast signal is supplied to the input side of the gain controller 29R via the switch 38, and the switch 40 changes the position of the bright line depending on the audio signal from one side of the video screen to the right side in FIG. 2A. Also, the output signal of the differentiating circuit 34L is grounded via a diode 41 and a switch 42.

Also, on the screen of the cathode ray tube 8, as shown in FIG.
When displaying the two waveforms St and SR based on the stereo signals obtained at the movable contacts 24a and 25a of No. 4 and 25, respectively, the second movable contacts 5a, 9a, 38a, 40a
and 42a to the respective third fixed contacts 5d, 9d, 38d
, 40d and 42d, respectively, and the movable contact 36a of the multipath signal display switch 36 is connected to one of the fixed contacts 3.
Connect to 6b.

At this time, the output signal of the video detection circuit 4 is not supplied to the video amplification circuit 7.

At this time, the brightness adjustment terminal of the video amplification circuit 7 is grounded via the resistor 10, so the background of the screen of the cathode ray tube 8 becomes relatively dark, making the bright lines easier to see.

Also, at this time, the stereo display lamp 44 lights up.

Also, movable contacts 5a, 9a, 38a, 40a and 42
a to third fixed contacts 5d, 9d, 38d, and 40d, respectively.
and 42d, and when the movable contact 36a of the multipath signal display switch 36 is connected to the other fixed contact 36c, the multipath signal can be displayed on the screen of the cathode ray tube 8, and this television John receiver can be used as a measuring device.

In the example shown in FIG. 1, the waveform is displayed on the screen of the cathode ray tube 8 by the display pulse signal obtained only in the even field or only in the odd field, and the waveform is displayed depending on the phase difference between the even field and the odd field. It is designed to eliminate sagging.

For this reason, in FIG. 1, the vertical pulse obtained by the vertical deflection output circuit 15 is supplied to the trigger pulse input terminal 45a of the flip-flop circuit 45, and the output terminal of this flip-flop circuit 45 is connected to each of the diodes 43L and 43R. The diodes 43L and 43R are connected to the cathode of the differential circuit 3 at every other field.
The output signals of 4L and 34R are not supplied to the adder circuit 35.

In such a television receiver as described above, the switching device 5
, 9, 38, 40 and 42 movable contacts 5a, 9a, respectively.
, 38a, 40a and 42a as the husband's third fixed contact 5
d, 9d, 38d, 40d and 42d, respectively, and the waveforms of the stereo signals obtained at the movable contacts 24a and 25a of the switching devices 24 and 25, as shown in FIG. 2B, are displayed on the screen of the cathode ray tube 8. When the television broadcast signal disappears and the horizontal synchronization signal supplied to one input terminal of the horizontal automatic frequency control circuit 11 disappears, noise appears at one input terminal of the horizontal automatic frequency control circuit 11. Therefore, the oscillation frequency of the horizontal oscillator 12 is disturbed, and there is a drawback that a good waveform cannot be displayed on the cathode ray tube 8.

In view of this, the present invention is designed to eliminate the blurring of the display of waveforms related to audio signals due to noise when there is no television broadcast signal.

An embodiment of the television receiver of the present invention will be described below with reference to FIG.

Example 1/i: In this case, a connection switch 46 is inserted between the horizontal deflection output circuit 13 and the other input terminal of the horizontal automatic frequency control circuit 11.
are closed, and the movable contacts 5a, 9a, 38a of the changeovers 5, 9, 38, 40 and 42, respectively.

40a and 42a are respective third fixed contacts 5d.

9d, 38d, 40d and 42d, respectively, and when viewing the waveform of the stereo signal etc. obtained at the movable contacts 24a and 25a of the switching devices 24 and 25, on the screen of the cathode ray tube 8, turn on this connection switch 46. Make it open.

Since the present invention is constructed as described above, the connection switch 46 is normally closed, so that the television receiver operates in the same manner as before.

In addition, the movable contacts 5a, 9a, 38a, 40a and 42a of the switching devices 5, 9, 38, 40 and 42 are connected to the respective third fixed contacts 5d, 9d, 38d, 40d and 42d, respectively, and the switching devices When viewing the waveforms of the stereo signals etc. obtained from the movable contacts 24a and 25a of the movable contacts 24 and 25 on the screen of the cathode ray tube 8, the connection switch 46 is opened and the horizontal oscillator 12 is brought into a free oscillation state. 1
It is made to oscillate at a natural frequency of 2, that is, a horizontal frequency.

Therefore, according to the present invention, even when the television broadcast signal disappears and the horizontal synchronizing signal supplied to one input terminal of the horizontal automatic frequency control circuit 11 disappears, the noise supplied to this one input terminal Since the waveform on the screen of the cathode ray tube 8 is not disturbed in any way, a good waveform can be displayed.

Incidentally, the present invention is not limited to the above-mentioned embodiment, and the above-mentioned connection switch 4
6, a connection switch is provided on the input side of the synchronization signal separation circuit 6 or between the synchronization signal separation circuit 6 and the horizontal automatic frequency control circuit 11, and this is normally closed when viewing the waveform of the stereo signal, etc. Of course, even if this connection switch is opened at the same time, the same effects as those of the above-mentioned embodiment can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the television receiver of the present invention, and FIG. 2 is a diagram for explaining FIG. 1. 4 is a video detection circuit; 5, 9, 38, 40, and 42 are respective switchers; 6 is a synchronization signal separation circuit; 7 is a video amplification circuit; 8
1 is a cathode ray tube, 11 is a horizontal automatic frequency control circuit, 12 is a horizontal oscillator, 13 is a horizontal deflection output circuit, 20 is an audio signal output terminal, 22L and 22R are recording signal input terminals, 2
6L and 26R are left and right channel signal input terminals, respectively, and 46 is a connection switch.

Claims (1)

[Scope of utility model registration request] In a television receiver in which a television image and a waveform related to an audio signal can be switched and viewed on the same cathode ray tube, the horizontal comparison pulse from the horizontal deflection output circuit is connected to the horizontal When the signal is supplied to an automatic frequency control circuit and only a waveform related to the audio signal is viewed, the connection switch is opened to disable the horizontal automatic frequency control circuit and put the horizontal oscillator in a free oscillation state. A television receiver characterized by: