SU788437A1 - Device for synchronizing vertical scanning of television receiver - Google Patents

Description

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The invention relates to television technology and can be used in receivers with BHq requirements for frame synchronization resistance. A device is known for cuecronization of a frame sweep of a revision receiver comprising a pulse shaping unit of double horizontal frequency, a frame sync extraction unit representing a coincidence circuit whose output is connected to the input of a frame sweep generator, and double signals are received at one of the matches of the coincidence circuit. line frequency. eleven.

However, in the known device protection of a frame sweep is not provided in the interval of its reverse stroke and the moment of the beginning of its forward stroke from 20 interference, which can displace the beginning of the forward stroke and thereby lead to instability of the television raster.

The purpose of the invention is to increase the reliability of frame scanning synchronization.

To achieve this goal, a television receiver frame synchronization device containing 30

a pulse shaping unit with a horizontal frequency, a frame sync pulse allocation unit, the output of which is connected to the first input of a vertical sweep generator, a key is entered, one input of which is connected to the output of the double horizontal frequency shaping unit, and the other to the second output of the vertical sweep generator, the second input of which connected to the output of the key.

The figure shows the Structural Electrical Circuit Device of a television receiver frame scan.

The device comprises a vertical scanning generator 1, a vertical sync pulse allocation unit 2, a double horizontal frequency pulse generating unit 3, and a switch 4.

The device works as follows.

Under the influence of an alternate personnel sync pulse, which is outputted at the output of block 2 and fed to the input of generator 1, the generator 1 tilts and starts the reverse run of personnel sweep. At this moment, a second pulse occurs on the second generator of the generator 1. key 4 is activated. Due to this, double-frequency frequency pulses generated by block 3 begin. to enter the second input of generator 1 as an additional clock signal. One of these double line frequency impulses is able to reverse the oscillator 1 and cause it to force and go into forward sweep mode. At this point, the end of reverse, the generator 1 pulse, supporting key 4 is in the open state, and the double-line frequency pulses no longer affect the operation of generator 1.

With the advent of the next frame sync pulse, a new cycle of device operation begins. Due to the shift of the frame sync pulse by an integer number of lines plus half lines and so on, that the beginning of the forward stroke of generator 1 is determined by double horizontal frequency pulses, the beginning of the forward stroke in one field of the television frame is strictly the same as the beginning of the line, and in the other {adjacent field) - matches exactly in the middle

line spacing.

. Thus, the introduction of a key into the device, through which the horizontal sweep generator is pulsed with a double horizontal frequency, and the control of this key by the vertical sweep generator pulses dramatically reduces the impact of interference (including horizontal frequency interference) and ensures in the television receiver the stability of the vertical sweep and good quality interlaced.

Claims (1)

1. US Patent No. 3184547, cl. 178-69 1965 (prototype)