SU1462511A2 - Device for remote synchronization of television camera - Google Patents

Abstract

The invention relates to a television technique and can be used to synchronize television cameras with a remote source of clock signals. The purpose of the invention is to improve noise immunity. The device contains a block of sampling and storage, controlled by rr, formers of sync pulses of lines and video and video signals, selector-sync pulses, phase detector, three communication channels, five triggers, four el-OR-NOT, seven electric Combi OR, two inverters, one-shot, peak detector and low-pass filter. These blocks characterize the performance of the chamber channel and the camera head. If, for any reason, there are no sync pulses from the output of the camera head, or they disappear, the camera sync code (CSC) takes on the value at which the sync pulse generation system goes into operation in an autonomous mode without auto-tuning the frequency and phase. In order to eliminate the influence of KSK signals on the video signal of the camera and thus reduce the noise introduced into the video signal, KSK is fed to two malicious signals OR, which are strobed by field pulses and only skip KSK during reverse of the sweep, when the image signal is not formed. To increase the stability of holding the synchronism, a filter smoothing the oscillation of the control voltage at the input of g is used. 4 il. with (L

Description

The invention relates to a technique of television and can be used for synchronization and television cameras with a remote source of clock signals.

The purpose of the invention is to improve noise immunity.

FIG. 1 is an electrical block diagram of a device for remotely synchronizing a television camera; in fig. 2-4 timing diagrams explaining the operation of the device.

A device for remote synchronization of a television camera (Fig. 1.) contains a sampling-storage unit 1, a controlled oscillator 2, a shaper of 3 sync pulses of a line, a shaper of 4 sync pulses of a field, a shaper of a video signal, a selector of 6 sync pulses, a phase detector 7, the first channel 8

GO

ten

15

20

25

connection, first, second and third triggers 9-11, first and second elements OR-NOT 12 and 1.3, first element Or 14, -first inverter 15, second element OR 16 ,. the third element is OR- NOT 17, the third element is OR 18, the second Inverter is 19, the fourth, sixth and seventh elements are OR 20-22, the third fi are the second channels 23 and 24 of communication, one is: a juvibrator 25, a peak detector 26, the fourth element OR - NOT 27, fourth and fifth triggers 28 and 29, fifth: element OR 30, low pass filter 31.

I A device for remote synchronization of a television camera is as follows.

From the video signal (Fig. 2 a, 3 a) in the c: electoral 6, synchro-impulses made: s (Fig. 2 b, 3 b), of which in the one-vibrator 25 the horizontal frequency pulses of duration O, 5H ( half line, Fig. 2 c, 3 c), 1: which enter the input of the phase detector 7, which is a D-trigger. These sync pulses are the master 51 sync pulses (Fig. 2 g, 3 g). The advance of the clock pulses extracted from the video signal relative to the 30 rto of the leading clock pulses of the timing diagram correspond to 2 a, with a delay of the clock pulse more strongly. from the video signal from- (regarding the leading clock pulses,

the gram of temporary processes in the pre-; | agam device match -ir. Zo

i Depending on the temporal position of these pulses, at the direct output of 40 phase detector 7, 1 information appears as O or 1 (Fig. 3 d, 4 d), and at the inverse output of the phase detector 7 yo is the antiphase information 45 (Fig. 2e, 3e). This information is. steps on the inputs of the second and third elements OR-NOT 13 and 17 and, passing through them (Fig. 2, h, 3, 3, h), goes to the outputs of the first and third - 50th BG of elements OR 14 and 18, through which it passes when there is information from the output of the peak detector 24, indicating the presence of sync signals at the input of the camera channel 55 from the output of the chamber head. If for some reason there are no sync pulses from the chamber head output or they disappear, then the sync code 14625114

The camera operation (CSC) takes the value 11 at the output of the first and third elements. OR 14 and 18.

The system for generating sync pulses remains in its previous state (in the state it was in the presence of — sync pulses), i.e. goes into operation in the autonomous mode without auto-tuning of the frequency and phase, preserving the phase and frequency of the previous state. To sample the resolution signal of the KSK transmission, there is a peak detector 6, which produces a signal O In the presence of clock pulses and 1 in the absence of them.

Through the third and second channels 23 and 24 of the communication, the KSK is fed to the inputs of inverters 15 and 19 and the inputs of the second and fourth elements SHSh 20 and 16, to the other inputs of which the information from the outputs of the second and first inverters 19 and 15, respectively, is fed, and to the third the inputs come in sync pulses from the generator of 3 pulses of the rows (Fig. 2 and 3 and). The first and second inverters 15 and 19 and the second and fourth elements 16 and 20 form the decoder of the camera synchronization code, i.e. they determine the sign of the detection of sync pulses and ensure its determination only in the presence of two paraphase ECCs, i.e. only if the code is 01 or 10. Moreover, this information in the XK decoder is gated with line clock pulses applied to the third inputs of the fourth and second elements OR 20 and 16 to reduce the dynamic phase error (Fig. 2, 3), and goes to block 1 sample storage (to generate a control voltage, which affects the controlled oscillator 2 and changes its frequency and phase).

In this case, when clock pulses are ahead, compared in phase detector 7, pulses are present at the output of the fourth element OR 20 (Fig. 2k) and a high potential at the output of the second element OR 16 (Fig. 2l), and for Holding sync pulses compared in the phase detector 7, at the output of the second element OR 16 are present. .pulses (Fig. 3 l) and at the output of the fourth element OR 20 there is a high potential (Fig. 2 k).

35

514

The controlled oscillator 2 amplifies the initial frequency on the order of 5 NHz to form the sync pulses of lines and fields. This frequency is fed to the shaper of 3 line sync pulses, which generates horizontal pulses and double horizontal frequency pulses to form field sync pulses.

Sync pulses of lines and fields, synchronous and in-phase with leading sync pulses, regardless of the length of the cable are kneaded into the video signal generated in the video signal shaper 5.

Typically, the cable length does not exceed one and a half kilometers, which, with an average signal propagation delay in a chamber cable of 5 µs / km, corresponds to a total maximum propagation delay of 15 µs, consisting of propagation delay in transmitting the video signal from the camera head to the camera channel and propagation delay KSK and not exceeding a quarter of the adjustment period of the auto-tuning system.

Such a construction of the system for autotuning the frequency and phase of the rows makes it possible to - - transmit the information on the time position of the HR sync pulses in the chamber channel to the SSC. Dp of this from the leading sync pulses (Fig. 4 a) and the leading sync pulses of the fields (Fig. 46), a frame frequency pulse is formed, tied to the beginning of the leading sync pulse of Figs. 4 c), which is fed to the information inputs of the second and third triggers 10 and 11, promoting this personnel pulse with a period of pulses of rows (fig. 4 d, d). In the first OR-NOT 12 element, a pulse is formed with a duration of two periods of lines (Fig. 4e, 3h), and the First and Third elements of OR 14 and 18 (Fig. 4i, g, k) are formed during these two lines The camera synchronization code in the form of a combination 00, which does not affect the auto-tuning of the frequency of the phases of the rows, since the passage of the third and second channels 23 and 24 of the communication is not decrypted by the fourth and second elements OR 20 and 16 and does not change the state block 1 sample-storage, but decrypted by the fourth element OR-NOT 27 (Fig. 4l and is fed to the input of the fifth trigger

11b

29, clocked by pulses of rows (Fig. 4 m) and used for assigning a personnel impulse provided by the fourth element OR-NOT 27.

From the direct output of the fourth trigger 28, a pulse arrives at the input of the fifth trigger 29, which performs the same functions and serves to confirm the reception of the frame information n to the second line. The pulses from the inverse output of the fourth trigger 28 (Fig. 4 m) and the inverse output of the fifth trigger 29 (Fig. 4 o), as well as the pulses of the rows (Fig. 4 n) are fed into the fifth. an element OR 30, from the output of which the frame synchronization signal (Fig. 4, is applied to the setup input of the generator 4 field clock pulses,

Dp eliminating the influence of XK signals on the video signal of the camera and thus reducing the noise introduced into the video signal, the camera synchronization code is fed to the input of the sixth and seventh elements OR 21 and 22, which are gated by field pulses and pass the KSK code only during the reverse sweep, when there is no video signal formation of the image, nor., Dn this, the second inputs of the sixth and seventh elements OR 21 and 22 receive the leading sync pulses of negative polarity.

At the moment when the sync pulses are not present at the output of the sixth and seventh elements OR 21 and 22 there are two signals 1, i.e. code 11, which puts the sync pulse shaping system into a frequency and phase hold mode.

The dp of increasing the stability of holding is the low-pass filter 31, which smoothes the oscillation of the control voltage at the input of the controlled oscillator 2.

Claims (1)

Invention Formula A device for remote synchronization of a television camera according to the author, its No. 1354442, is necessary so that, in order to improve noise immunity, the sixth OR element is additionally inserted between the output of the first OR element and the input of the third channel connection, the seventh element OR, connected between the output of the third element IL and the second communication channel, and so 14625118 the same low-pass filter, the included OR elements, are combined with the output of the sample-storage unit, the home of the device field clock pulses, and the input of the controlled oscillator, for remote synchronization during this, other inputs of the sixth and seventh. levizionnoy. Cameras / Caia Phases. one Fyyo.2. kl E + - Kamerna eo / y8kl t g: g j l2 "irSJ r L f Mir-ir-l nr-innr-ir-TT nc , i .t It