SU1626452A1 - Device for automatic tv receiver tuning - Google Patents

Abstract

The invention relates to a television (TV) technique and can be used in the manufacture of TV receivers. The purpose of the invention is to increase the speed and simplify the device. The device includes a tuning control unit 1, consisting of a reference generator 2, a key 3, a cumulative counter 4 and an RS flip-flop 5, a control generator 6 of the tuning voltage and a block 7 of the g-automatic frequency tuning of the local oscillator. At the initial moment (there are no frame sync pulses (XI) at the device input), the cumulative counter 4 overflows and sets the RS-tripper 5 to the O state. At that, the key 3 opens and the signal from the reference generator 2 goes to the controlled generator 6, which causes a change voltage at its output. When the output voltage of the device approaches the value corresponding to the frequency setting of the TV transmitter, the PSI is indicated. The CSI sets cumulative counter 4 to the state O, which starts counting pulses from reference generator 2. Before the next CSI arrives, a well-defined number of pulses are counted. When properly configured at the output of the cumulative counter 4, a signal appears that sets the B5-flip-flop 5 to state 1, the key 3 closes, the voltage at the output of the controlled oscillator 6 does not change and unit 7 is turned on for final tuning. 1 il.

Description

The invention relates to a television (TV) technique and can be used in the manufacture of TV receivers.

The purpose of the invention is to increase the speed and simplify the device.

The drawing shows a structural electrical circuit of the device.

The device comprises a tuning control unit 1, consisting of a reference generator 2, a key 3, a cumulative counter 4 and an RS flip-flop 5, a control generator 6 of the tuning voltage, and a unit 7 for automatically adjusting the local oscillator frequency.

The device works as follows

At the initial moment of time, the output voltage of the device, which is the sum of the voltages from the output of the controlled generator 6 and the voltage generated directly by the block 7, does not ensure the TV receiver to be tuned to any TV channel. Consequently, the frame clock pulses at the input of the device are absent and accumulative counter 4 is not reset to the zero state. The pulses generated by the reference generator 2 are sent to the counting input of accumulative counter 4, which overflows and sets the RS flip-flop 5 to the state O, the key 3 is switched to the open state, and the 7th state unit is disabled. In this case, the pulses generated by the reference generator 2 pass through the switch 3 and, being fed to the control input of the controlled generator 6, change the voltage at its output, and hence at the output of the device.

When the output voltage of the device approaches the value corresponding to the frequency setting of the television transmitter, a frame synchronization signal appears. Each frame sync pulse sets cumulative counter 4 to the zero state. The pulses coming from the reference generator 2 begin to fill cumulative counter 4. Before the next frame sync pulse arrives, the cumulative counter 4 will have time to calculate a strictly defined number of pulses. With proper tuning, this mode repeats regularly with a period; equal to the period of the following personnel sync pulses. In this case, the output

cumulative counter 4 a signal appears that sets the RS flip-flop 5 to state 1. The key 3 closes, the pulses from the reference oscillator 2 are not received by the controlled oscillator 6 and the voltage at its output does not change, block 7 simultaneously turns on final setting.

Increased speed is achieved due to the fact that at the time of capture

The frequency of the television transmitter is tuned for one period of the following frame sync pulses.

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Claims (1)

Invention Formula A television receiver's automatic tuning device, containing a series-connected controlled voltage setting generator and The automatic frequency control unit of the local oscillator, the output of which is the output of the device, and the control inputs of the controllable tuning voltage generator and the automatic frequency control unit of the local oscillator are connected respectively to the first and second outputs of the control control unit containing a key, a cumulative counter and RS -trigger, the output of which is combined with the control input of the key, the input of the zeroing of the cumulative counter is the input for the frame sync pulses, and the first output of the cumulative counter is connected to the S input of the RS flip-flop, which is different from the fact that, in order to increase speed and simplify the device, into the unit control unit, a reference generator is introduced, the output of which is connected to the key input combined with the counting input a cumulative counter, the second output of which is connected to the R input and the RS flip-flop, the output of which is the first output of the tuning control unit, the second output of which is the key output.