SU1619418A1 - Device for automatic switching-off of tv receiver - Google Patents

Description

one

(21) 4608514/09

(22) 11/23/88

(46) 07.01.91. Bnsh. № 1 (72) V.F.Yangol

(53) 621.397 (088.8)

(56) Khaidakov A. Automatic switch-on TV. - Radio, 1984, No. 11,

with. 26-27.

(54) AUTOMATIC TURN-OFF DEVICE OF A TELEVISION RECEIVER

(57) The invention relates to television technology and can be used in television receivers. The purpose of the invention is to improve the noise immunity. The device for automatic shutdown of the television receiver 9 contains bandpass filters 1 and 3, frequency detector 2, rectifier 4, current driver 5, time master unit 6, threshold unit 7, switching unit 8. In the absence of a television program or a large frequency instability line sync pulses at the output of the detector 2 appears a variable component of the voltage, which through the filter 3 ensures the operation of the block 8. In the presence of a television program, the constant voltage from the output of the detector 2 does not go through through the filter 3. In this device does not prevent the use of a television receiver as MC-Nitori. 1 il.

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The invention relates to television technology and can be used in television receivers.

The purpose of the invention is to improve the immunity "

The drawing shows a block diagram of the device.

The automatic receiver of the television receiver contains the first band-pass filter 1, the frequency detector (QD) 2, the second band-pass filter 3, the rectifier 4, the current driver 5, the time setting unit 6, the threshold unit 7, the switching unit 8 and the television receiver (TP) 9.

The device works as follows.

After switching on, TP 9 is energized on all its circuits and from it on the circuit breaker. Due to the timing of the driver unit 6, the relay 8 is turned on and will block an unshown mains switch for the duration of the warm-up period. If after this time at the output of the filter 1 there appear horizontal sync pulses with a constant tracking frequency, our telecentre reception unit, Shn. same they

will be permanently absent (for example, VCR stop mode), then a constant voltage proportional to this frequency appears at the output of BF 2, but it does not pass through subsequent blocks of the device, i.e., relay 8 remains in the on state. When the clock frequency is non-constant, for example, in the case of a loss of a telecentre signal, a variable component appears at the output of PC 2, which, having passed through filter 3, is rectified by the rectifier L and the charging time in the block 6 begins to charge arising at the output of the driver 5. When a certain voltage is reached, the threshold unit 7 operates and turns off the relay 8, which, in turn, turns off the TP 9 from the network.

Manual switching off of the TP is performed by the normally-open button contacts (not shown) in the power supply circuit.

TP 9. Time driver unit 6 prevents false triggering of the device,

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for example, due to the switching of TP channels.

The proposed device has increased noise immunity compared to the known one, because of all types of interference, only a powerful harmonic signal without any modulation at the frequency of the received channel can prevent the TP from being disconnected from the network at the end of the transmission, while the known device can take as a television signal the usual industrial and domestic interference or harmonics of the radio station signals. But the situation with a powerful disturbance at the frequency of reception can not be, as she would have blocked the signal of the television center. In addition, the appearance of an unmodulated signal in itself is very unlikely. In all other cases, the disappearance of the telecentre signal causes the appearance of noise (snow on the screen) or, consequently, random pulses at the output of the synchro-selector TP, and this causes the device to trip.

Thus, due to BH 2 and filter 3, the device has a higher n in comparison with the known noise immunity. F o j m v l and invented

The automatic switch-off device of the television receiver, which is connected to the first band pass, whose input is the input of a horizontal sync pulse, is connected to a rectifier, a current driver, a driver unit and a threshold unit, the output of which is detected from the controller the entrance of the commision terminal 6-. the input of which is the input for the power supply voltage of the television receiver, the output of the switching unit is the output for the voltage supply of the television receiver, which is introduced in order to increase the noise immunity, frequency detector, the input of which is connected to the output of the first band - pass filter, the output of the frequency detector is connected to the input of the inputted second band pass filter, the output of which is connected to in :. single straightener

Claims (1)

Claim A device for automatically turning off a television receiver containing a first band-pass filter, the input of which is an input for horizontal sync pulses, serially connected by a rectifier, a current driver, a time-setting unit and a threshold unit whose output is connected to the control input of the switching unit. ' the input of which is the input for the power supply voltage of the television receiver, the output of the switching unit is the output for the power supply voltage of the television receiver, it is important that, in order to increase the noise immunity, a frequency, detector, input is introduced · Which is connected to the output of the first band-pass filter, the output of the frequency detector is connected to the input of the introduced second band-pass filter, the output of which is connected to the input of the rectifier.