SU824479A1 - Digital device for automatic control of frequency and phase of synchronizing pulses - Google Patents

Description

the second reference frequency generator 4, mode switching unit 5 and electronic switch 6.

The device works as follows.

In the absence of external sync pulses at the input of the device, the mode switching unit 5 generates a signal in the form of a level, respectively. corresponding to the logical O. In this case, the electronic switch 6 passes to the input of the divider 3 frequency high-frequency pulses coming from the generator 1 and passing through the phasing unit 2 directly.

With the appearance of external clock pulses, block 2 generates packets of phase pulses in the honey front edge of the external clock and its own. Phasing pulses are stacked. with high-frequency pulses of the generator 1, as a result of this an output mixture of pulses appears at the output of the phasing unit 2.

Adding or subtracting pulses to the input of the divider 3 frequencies, respectively, leads to a decrease or increase in the period of follow-up of the pulses produced by the divider. Thus, phasing of the generated pulses is performed. At the end of the phasing, when the leading edges of the generated pulses coincide with the leading edges of the external clock, the mode switching unit 5 generates a control signal to the electronic switch b in the form of a logical level that switches the device to the slave mode. In this case, the electronic switch 6 transmits to the input of the splitter 3 frequency high-frequency pulses of the second generator 4, which are associated with a certain phase relationship with the external sync pulses.

When the external clock pulses disappear, the output of the mode switching unit 5 appears logical O, which switches the automatic frequency control device

and the phases of the clock pulses in the autonomous mode, which is operated from a quartz oscillator.

Thus, introducing into the known device a second reference frequency generator, an electronic switch and a mode switching unit allows phasing of clock pulses, and after phasing is over, switching the device to slave mode and operating from the second synchronized generating frequency, the pulses of which are already connected to certain phase relation with external sync pulses. As a result, the required stability of the sync pulse period is provided at a lower reference frequency.

Claims (1)

Invention Formula A digital device for automatically adjusting the frequency and phase of the sync pulses, containing a series-connected reference frequency generator and a phasing unit, to the second input of which external clock pulses are applied, and a frequency divider, characterized in that, in order to improve the stability of the sync pulse period, an electronic switch is inserted the second reference frequency generator and the mode switching unit, the output of the phasing unit and the output of the second reference frequency generator are connected respectively to the first and second inputs Dami electronic switch, the third input of which is connected to the output of the mode switching unit, and the output is connected to the input of the frequency divider, while the first input of the mode switching unit and the third input of the phasing unit are combined and connected to the output of the frequency divider, and to the second generator The input of the mode switching unit is supplied by external clock pulses. Sources of information taken into account in the examination 1. US Patent No. 3562661, cl. 311-10, 1971 (prototype).