SU373867A1 - (PAGSYTNO-GSH: -.--.. SELECTOR OF THE RADIO IMPULSE SIGNAL OF SYNCHRONIZE1 | andBNB.PIST • ^^^ • D '^ ck- ^ ddd.d, ^^ _ ^ "" ^' • '^ "' ^ • "- • --V -.— g- ^ tvaff. - Google Patents

Description

one

The invention relates to the field of television technology, in particular to devices for synchronizing television systems.

A radio pulse synchronization signal selector is known, which contains an input signal gating unit connected in parallel to the inputs and a band-pass filter whose output through an envelope detector, a selective element and a gating pulse driver are connected to the second input signal gating unit.

However, the known selector has insufficient noise immunity.

In order to increase the noise immunity in the proposed selector, a phase shifter is switched between the output of the selective element and the input of the gating pulse shaper.

The drawing shows the block diagram of the proposed selector.

The described selector contains a band-pass filter /, an amplitude detector 2 of the radio pulse envelope, a shaper 3 of gating pulses, an input signal gating unit 4, a selective element 5, for example a resonant amplifier, a phase shifter 6.

In the selector, the processing of the synchronization signals to the resonant amplifier is performed in the same manner as in known devices.

In a resonant amplifier tuned to the frequency of the radio pulses (for example, the line frequency of a television signal), the first harmonic, a sinusoidal signal of the radio frequency, is extracted from the signals of the radio pulse envelope. This signal, the passage through the phase shifter, changes in phase and enters the gate pulse shaper. AT

In this block, the sinusoidal signal is limited in amplitude symmetrically with respect to the zero line to eliminate amplitude modulation in the presence of interference or when the signal is output from one or two radio pulses. From the P-pulses of the repetition frequency of the radio pulses, gating pulses are generated, which are used to control the gating unit of the input signal.

The phase shifter provides the possibility of changing the temporal position of the gating pulses relative to the sync pulse. This makes it possible, if desired, to synchronize with a pulse located in the television signal after a packet of a sinusoidal signal, as in known devices, as well as with a pulse located in front of the radio pulse. As a result of the installation in the selector of the resonant amplifier, the effective bandwidth of the gate of the gating pulses is 10–20 times less than the frequency band of the television singhal and is completely determined by the bandwidth of the resonant amplifier.

In the device, only those interferences, the filling frequency of which is equal to the frequency of filling of radio pulses, can pass through the gate of the gating pulses, and the repetition frequency is equal to the frequency of radio pulses. The probability of occurrence of such interference is much less than random, occasional interference with the frequency of filling the radio pulse, which can be freely passed to the channel output in known selection devices.

Subject invention

A radio pulse synchronization signal selector comprising an input signal gating unit and a band-pass filter connected in parallel through the inputs and an output filter through an envelope detector, a selective element, such as a resonant amplifier, and a gating driver, connected to the second input of the input gating unit, characterized in that in order to increase the noise immunity of the selector, a phase shifter is turned on between the output of the selective element and the input of the gating pulse shaper.