SU648152A3 - Decoder of 'sekam'colour tv receiver - Google Patents

Description

The MHbd EGho source is connected to one of the inputs of the pulse generator and the input of the matrix, two detectors are introduced, Two threshold elements, for example, a Schmitt trigger, logical elements And and NOT, and a pulse extender, with the inputs of the logic element and sequentially connected faults, logic elements of the logic element and the pulse extender, and the inputs of the logic element and the sequentially connected phase elements, the logic element and the pulse extender, and the inputs of the logic element and the sequentially connected phase elements, the logic element and the pulse extender, and the inputs of the logic element and the sequentially connected phase elements the threshold element is connected to the outputs of the amplifiers of the color signal processing channel, the output of the logic element I is connected to the second input of the chopper and through the logical element NOT and the expander impu Lsov - with the second input of the pulse former.

The drawing shows a structural electrical circuit of the proposed device.

The SECAM color television receiver decoding device contains a color video signal processing channel consisting of an output filter I decorrection, the output of which is through amplifier 2 and series-connected delay line 3 and amplifier 4 is connected to the inputs of the electronic switch 5, and the output of the latter through series-connected frequency detectors 6 and 7, and the inverse correction filters 8 and 9 are connected to two inputs of the matrix 10, and a block for processing a color video signal processing channel, consisting of a chopper 11, on one from the inputs of which a personnel pulse is applied, and its output is connected to one input of trigger 12, the second input of which is connected to the source of a personnel pulse (not shown), the output of this source is connected to one of the inputs of the imaging device 13 pulses, the output of which is connected to the third input matrix 10.

The device also contains two. phase detectors 14 and 15, two threshold elements 16 and 17, for example a Schmitt trigger, logic elements AND 18 and NOT 19 and a pulse extender 20, with inputs of element And 18 through successively connected phase detector 14 and threshold element 15 and through consecutively connected phase detector 15 and the threshold element 17 are connected to the outputs of amplifiers 4 and 2, respectively. The output element And 18 - with the second input of the chopper 11 and through the element NOT 19 and the expander 20 - with the second input shaper 13 pulses.

The device works as follows.

The input signal is fed to the input of the filter 1 of the decorrection, which compresses the preliminary correction

on podnesuvdy frequency, carried out by radiation. From filter 1, the signal goes in parallel to the amplifier 2 and through the delay line 3 to the amplifier 4, from their outputs the signal goes to the INPUTS of the electronic switch 5, controlled with the horizontal scanning frequency. From the output of the electronic switch 5, depending on

whether it is blue or red, the signal is fed to frequency detector 6 or 7 and through filter 8 or 9 respectively to the matrix 10 produced by three chrominance signals.

Random subcarrier failure

frequencies are detected by a detector 15, emitting, for example, positive signals. The output signal of the detector 15 is fed to the input of the threshold element 17, which transitions to a state of one when the amplitude of the input signal exceeds the threshold value M, and to a zero state when the amplitude of the input signal

signal less than the other threshold

values of m -4 M. At the input signal, the amplitude of which is between m and M, threshold element 17 retains the previous state. The excess of the input signal of the value M indicates the presence of a subcarrier frequency, the reduction of the input signal to a value less than the No. indicates the absence of this subcarrier.

In practice, the chromaticity channels must be not-a-bit not only on the P-th line, where there is no subcarrier frequency, but also on the (P + 1) -th yroc, since the chromaticity signals,

 used for the (n + 1) -th row, generated using information transmitted by the subcarrier frequency during the n-th and (n + 1) -th rows. For this, serve detector 14,

O to the input of which a signal is received from amplifier 4, and the threshold element 16. The output signals of the threshold elements 16 and 17 are fed to the inputs of the element E 18 and further to the element NOT

5 to 19, the output signal of the latter is applied to a pulse spreader 20, extending the signal to the element HE 19, compensating for the delay associated with the inverse correction. The output signal of the expander 20 pulses through the shaper 13 pulses is fed to the third (for) returning input of the matrix 10. The output signal of the And 18 element is also fed to the input of the interrupter 11, to another input of which a personnel impulse coincides with the middle part of the forward period Code by lines in the interval of the frame. The output signal of the chopper 11 is supplied in the presence of a subcarrier frequency to one of the inputs of the flip-flop li, and to its other input pulses of frame synchronization are given. From the output of the trigger 12, the signal is fed to the second input

5 shaper 13 pulses.

Claims (1)

1. The patent of France No. 1509936, cl. H 04 W 11,12.67. KI 1CO-s; t: yy