SU748908A1 - Colour synchronization device of tv receiver in pal/secam system - Google Patents

Description

: 54) COLOR SYNCHRONIZATION DEVICE

TELEVISION RECEIVER SYSTEM PAL / SECAM

The invention relates to television and can be used in combined television receptions ax of the PAL / SECAM system.

A PAL / SEC7 M television color locker device is known that contains a gated resonant amplifier, a synchronous detector, an integrator and an amplitude detector, serially connected, and horizontal pulses are fed to the control input of the gated resonant amplifier, and the output is connected to a phase shifter, a color subcarrier generator, a com. switchboard and control unit l.

However, the known device has a very complex functional scheme, which prevents its use in color television receivers.

The purpose of the invention is to simplify the device by eliminating an additional frequency detector.

For this purpose, in the n-jl / CEKAM system of a color receiver of a television receiver, containing a gated resonant amplifier, a synchronous detector, an integrator and an amplitude detector, the horizontal pulses are fed to the control input of the gated resonant amplifier, and the output is connected to a phase shifter, a color generator subcarrier, switch and control unit KOMKtytator, the output of the phase shifter is connected to the first input of the switch, the swarm of which is connected to the generator of the color subcarrier s, an output coupled to another input of the synchronous detector and a control input - with the output of the switch control unit, which is connected with the input amplitude

15 by the detector, and personnel clock pulses are fed to the counting input.

The drawing shows a structural electrical block diagram of the proposed 2Q device.

Claims (1)

The color receiver of the television receiver system PAL / SECAM contains a gated resonant amplifier 1, a synchronous detector 2, a phase shifter 3, an integrator 4, an amplitude detector 5, a commutator 6, a generator 7 of a color subcarrier, a control unit 8 Ro switch. The device works as follows. When a black-and-white program is received, the blocking potential at the blocking input of control unit 8 of the switch 6 is not received and the frame pulses applied to the counting input change its state in the beginning of each field,. At the output of the switch control unit, a square wave of a half-frame frequency is extracted, which at the beginning of each field changes the state of the switch. When the switch connects the input of the synchronous detector 2 to the output of the phase shifter 3, the circuit provides demodulation of the lower-case recognition signals SECAM. In the second case, when the synchronous detector input is connected to the output of the 7 color subcarrier generator, the device provides demodulation of the color flashes of the PLL signal. Such a device mode is idle. When the CECAM signal is received, the output of the gated resonant amplifier 1 separates packets of the non-modular color subcarrier bathroom with frequencies of 4.25 and 4.406 MHz, which alternate from line to line. Let at this moment the switch b connects the synchronous detector 2 to the output of the phase rotator 3. The color subcarrier packets arrive at the first input of the synchronous detector directly, and the second through the phase rotator 3, the frequency deviation converts into a phase change. At the output of a synchronous detector, bipolar pulses of a semi-line frequency are extracted. The integrator 4 of the semi-line frequency makes it possible for them to go to the decoder (at the output of the device, not shown in the drawing), where it implemented the color synchronization of the symmetric trigger that controls the color signals. Amplitude detector 5 bursts a half-line frequency wave. The resulting potential Eu (:, r. Includes the decoder's Chromatic channels and at the same time blocks the control unit 3 by the switch, supporting it in static mode, which corresponds to the reception of the SECAM signal. If at the moment of arrival of the SECAM signal, switch 6 is in such a position that it is synchronous Detector 2 is connected to a generator of 7 color subcarriers, then on the V-Schrocht detector, instead of a wave of a semi-linear frequency, there is an obstacle that goes 1P | WATCH t; I through the integrator 4. Switch on the next time, when providing-ay-ts d-modulation of recognition signals SECAM. Similarly, when receiving the signal PAL noise, it stops when the PAL signal is demodulated. Thus, the potential at the output of the amplitude detector 5 depends on color iri black-and-white program regardless of the system.The output potential of the switch control unit 8 depends on the type of system.When a black-and-white program is received, Eupr changes with a half-frame frequency, when receiving a signal, CECAM corresponds, for example, measures, a logical unit, and when receiving a PAL signal - a logical zero. Therefore, the potential Eupr is supplied to the inputs of a decoder controlling the switching of PAL / SECAM circuits, as well as an indicator indicating the type of system received. The proposed device uses only lower case recognition signals and provides automatic switching of decoder circuits in accordance with the type of color television system received. It excludes eight elements of the functional circuit of the prototype: a compensating amplifier, delay lines, a phase detector, a frequency detector, four phase-shifting circuits. The implementation of the invention will allow creating a PAL / SECAM combined color body for export with a fully automatic transition from receiving one system to receiving another and indicating the type of system being received. Such a TV will provide text information during the frame scan reverse, (Teletext system with high speed selection of the received page. The invention: Color synchronization device of the television receiver of the U SECAM system, containing a series-connected gated resonant amplifier, a synchronous detector, an integrator and an amplitude detector, the control input of the gated resonant amplifier is fed by lower-case pulses, and the output is connected to the phase shifter, the generator color sub, carrier, switch and switch control unit, characterized in that, in order to simplify the device by eliminating an additional frequency detector, the output of the phase shifter is connected to the first input of the switch, the second input of which is connected to the color subcarrier generator, the output is connected to another synchronous input detector and the control input with the output of the control unit by the switch, whose input is connected to the amplitude detector, and frame clock pulses are fed to the counting input. Sources of information taken into account in the examination 1, USSR Copyright Certificate, №415831, cl. H 04 N 9/50, 1976 (prototype). 748908