SU536622A2 - TV sync generator - Google Patents

Description

(54; TELEVISION SYNCHROGENERATOR

one

The invention relates to television technology and can be used in alphanumeric message synthesizers and video terminal devices of automated control systems.

By bus. St. No. 482917 is known a television sync generator containing serially connected master oscillator, a counter for the number of character elements horizontally, a counter for the familiarity along the line, a counter for the number of rows in the vertical sign, a counter for the number of rows, as well as a horizontal and frame impulse generator, a stop signal generation unit and an output clock switch unit.

However, the well-known television sync generator does not provide automatic coordination of image scales horizontally from several television sources of information.

The purpose of the invention is to provide automatic alignment of image scales horizontally from several television information sources.

To do this, a serially connected decoder, a phase detector, a key and a low-pass filter, whose output is connected to the second input of the master oscillator, are entered into a well-known television synchro generator, and the decoder input is connected to the second output of the familiarity count number along the line, and the second input of the phase detector is fed an external clock signal, and the control key input is connected to the auxiliary output of the clock switching unit.

The drawing shows a structural diagram of the proposed television clock generator.

The synchronous generator contains serially connected master oscillator 1, a counter 2, the number of elements of the sign horizontally, a counter 3 numbers familiarity along the line, counters 4 the number of rows in the sign vertically, a counter 5 the number of rows, and a block forming the stop signal 6, the output of which is connected to the inputs of the master oscillator 1 and the counters 2, 5, the generator 7 horizontal sync pulses.

8 frame clock pulses, the outputs of which are connected to the switching unit 9 of the clock signal, as well as the serially connected decoder 10, phase detector 11, key 12 and low pass filter 13, the output of which is connected to the second input of the master oscillator 1, and the input of the decoder 10 is connected to the second the output of the counter 3 is familiar numbers along the line, while the second input of the phase detector 11, the second input of the switching unit 9 and the input of the block forming the stop signal 6 are supplied by an external clock signal, and the control input of the key 12 is connected To the additional output of the switching unit 9 clock signal.

The clock generator works as follows.

In the case when the sync generator is not supplied with a sync signal from an external television system, the key 12 is in the disconnected state, the master oscillator 1 operates in an autonomous mode and the sync generator operates in the same way as the sync generator of the basic invention.

If an external sync signal is applied to the clock generator input, the key 12 closes the circuit of automatic tuning of the frequency of the master oscillator 1.

At the same time, the signal of the phase detector 11 through the switch 12 and the low-pass filter 13 automatically sets the frequency of the master oscillator at which it operates during the intervals between successive stop states, at which the time scale of the synchronous generator horizontally coincides with that of the leading television system. Moreover, if the setting of the frequency of the master oscillator 1 is equal to the required one, then the stationary mode of operation of the synchronous generator is established almost instantaneously (without a transient, since the error signal at the input of the filter 13 is absent.

In the future, regardless of the nature of the installation, the required frequency is maintained automatically, compensating for the possible destabilizing effect of temperature changes, supply voltage and. t. n.

Thus, in the proposed television synchro-generator, the frequency of the master oscillator is ensured, and the scales of the images of the slave and master television systems are automatically matched, which, in turn, ensures stable joint operation of several television systems in cases where their scale and accuracy images is one of the most important parameters for their functioning.

Claims (1)

Invention Formula TV sync on aut. St. No. 482917j, distinguishing is that, in order to ensure automatic coordination of image scales from several television sources of information, serially connected decoder, phase detector, key and low pass filter, the output of which is connected to the second input of the master oscillator, and the decoder input connected to the second output of the count of the familiarity number along the line, while the second clock signal is supplied to the second input of the phase detector, and the control input of the key is connected to the auxiliary output of the block to switching signal sync.