SU653774A1 - Device for identification and switching-off of colour unit of "pal-secam" receiver - Google Patents

Description

The invention relates to radio engineering and can be used in decoding devices of color televisions of the PAL, SECAM and PAL SECAM systems.

A device for identifying and deactivating a color block of a television receiver of the PAL-SECAM system containing the first OR element, the first input of which receives a signal from the frequency detector of the SECAM system, the second input has a signal from the phase detector of the PAL system, and the output is connected to the first the correction pulse generator input, the generator of rectangular pulses, on the control inputs of which the horizontal frequency pulses are applied, an asymmetrical trigger, a differentiating circuit, at the input of which the field frequency pulses are fed, and the output oedinen to the input limiter, second and third members OR 1.

However, the known device contains an additional frequency detector and mechanical switches for switching from one system to another.

The purpose of the invention is to simplify the devices.

For this purpose, in the device for identifying and deactivating the chromaticity block of the television receiver of the PAL-SECAM systems containing the first OR element, the first input of which receives a signal from the frequency

the detector of the SECAD system, the second input is a signal from the phase detector) of the PAL system, and the output is connected to the first input of the correction pulse generator, a generator of square pulses, on the control inputs of which horizontal pulses are fed, an asymmetrical trigger differentiating the circuit the input of which is applied to the frequency field pulses, and the output is connected to the input of the limiter, the second and third elements OR, the paraphase outputs of the correction pulse generator are connected to the first inputs of the second and third elements OR, the second inputs are cat These are connected to the output of the limiter, the output of the second element OR is connected to the input of the generator of rectangular pulses, the output of the third element OR to the input of the asymmetric trigger.

Claims (2)

The drawing shows a structural electrical circuit of the proposed device. The device for identifying and deactivating the color unit of the television receiver of the PAL-SECAM systems contains the first element OR 1, the first input of which receives a signal from the frequency detector of the SECAM system, the second input receives a signal from the phase detector of the PAL system, and the output is connected to the first input correction pulse generator 2, square pulse generator 3, the horizontal control pulses are fed to the control inputs of the standard frequency, the asymmetrical trigger 4, the differentiating circuit 5, to the input of which the field frequency pulses are applied and the output is connected with the input of the limiter 6, the second and third elements OR 7, 8, paraphase outputs of the correction pulse shaper 2 are connected to the first inputs of the second and third elements OR 7, 8, the second inputs of which are connected to the output of the limiter 6, the output of the second element OR 7 is connected to the input the generator of rectangular pulses 3, and the output of the third element OR 8 - with the input of the asymmetrical trigger 4. The device operates as follows. Suppose that a black and white image signal is supplied to the input of a color block, and the color block is turned off (the initial state). The input clock of the differentiating circuit 5 receives a personnel synchronizing pulse, which, having passed through it, takes the form of two short opposite-polarity pulses. The one-sided limiter 6 will pass only negative pulses to the maximum. These pulses through the element OR 7 are fed to the generator of rectangular pulses 3 and change from frame to frame, i.e. with a half-frame frequency, the phase of the rectangular pulses produced by it. At the same time, negative pulses from the output of the one-way limiter 6 through the element OR 8 arrive at the asymmetrical trigger 4 and keep it in the state in which the chromaticity block is turned off. At the same time, there is no signal at the input of the element OR 1, and, consequently, at the outputs of the gated pulse frequency generator 2 with the horizontal frequency. Let the color image signal go to the input of the chroma block, the square pulse generator 3 operates in the correct phase until the time when the black hole output (SECAM and PD output PAL is missing the signal obtained from the subcarrier detection located on the rear pad of the horizontal quench impulse trigger. Therefore, the asymmetrical trigger 4 is also in a state in which the chromaticity unit is turned off, i.e., in this case, the state of the circuit is similar to the one described above. The negative pulse of the frame frequency is sent from the output of the one-sided limiter 6 to the square impulses 3. The square impulse phase changes to an incorrect one. At the output of the PD "SECAM or PD" PAL, the signal received from the detection of the subcarrier located on the rear platform of the horizontal damping pulse, which, after the passage of the element OR 1, is gated with the horizontal frequency pulses of the correction pulse shaper 2. From the first paraphase output, the correction pulse through the element OR 7 is fed to the square pulse generator 3 and with a small delay corrects the phase of its operation to the correct one. Simultaneously from the second para-phase output gated by the horizontal frequency of the correction pulse importer 2, the impulse through the element OR 8 is fed to the input of the asymmetric trigger 4 and translates it into the state corresponding to the inclusion of the color block. In the wrong phase of the generator of rectangular IA1 pulses 3, at the time when the first paraphase output of the corrector 2 pulse gated with the horizontal frequency produces a pulse, which through the OR 7 element is applied to the square pulse generator 3, its phase changes to the correct one. . Simultaneously, from the second paraphase output gated by the horizontal frequency of the pulse shaping device and 2, the pulse through the OR element 8 is fed to the unbalanced trigger 4, which includes a chromaticity block. Thus, the proposed device provides, when receiving a color image, the inclusion of a color block and recognition. The proposed device differs from the known ones in that it does not require an additional frequency detector and mechanical switching when switching from one color television system to another. The invention The device for identifying and deactivating the chromaticity block of the television receiver of the PAL-SECAM systems containing the first OR element, the first input of which is fed from the frequency detector of the SECAM system, to the second input is the signal from the phase detector of the PAL system, and the output is connected to first entrance shaper 56 pulse correction, the generator of right angle copes OR, the second inputs of which are connected pulses, the control inputs of which are yen with the output of the limiter, the output of the second are given horizontal frequency pulses, some element OR is connected to the input of a square pulse, and The circuit, to the input of which pulses are supplied, the course of the third element OR - with the input of the infrequent fields, and the output is connected to the input of a symmetric trigger. the limiter, the second and third elements of the sources of information taken into consideration, characterized in that, in order to simplify the examination device, paraphase outputs form-1. Technical description of the color block worldspeaker impulse corrected connected by a stelvizor the first entrances of the second and third elements of TS-3202, SP-II, Vengri, 1975. 653774 Tpol