JPH0723252A - Multi-input synchronizing signal generating system - Google Patents

Abstract

PURPOSE:To allow the system to cope with instantaneous changeover by fixing the priority of input signals GL.VBS IN and GL.SC IN and selecting automatically either of the signals to use easily a synchronizing signal generator. CONSTITUTION:A synchronizing signal generator in synchronization coupling with a composite video synchronizing signal (GL.VBS) or a sub carrier signal (SC) being an output of a rubidium oscillator has an input sensing function of the GL.VBS signal and the SC signal, the generator is automatically synchronized-coupled with the GL.VBS when the GL.VBS signal and the SC signal are simultaneously received and the generator is automatically synchronized-coupled with the received signal when only one of the GL.VBS signal and the SC signal is received and the generator outputs a stable synchronizing signal oscillated in itself when both of the GL.VBS signal and the SC signal are received.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color television synchronizing signal generating system.

[0002]

2. Description of the Related Art A conventional embodiment is shown in FIG. 201 is a switching unit, 202 is a synchronous coupling and signal generation unit, and 205 is a SW for controlling the switching unit. Conventionally, the input signal for the synchronization coupling of the synchronization signal generator is the composite video synchronization signal (VB
S) was the mainstream, but recently, due to FS (frame synchronizer), the ratio of synchronous coupling to the composite video signal is reduced, and a more stable synchronization signal output is obtained.
(Rubidium) Subcarrier signal (S
It has become more common to use C) as an input to the synchronization signal generator. Therefore, the synchronization signal generator uses GL / VBS, G
L / SC, or when there is no input signal
The functions of 3 modes are required. In FIG.
When GL / VBS IN and GL / SC IN are input, the control switch 205 is used to manually set the input signal mode that the user wants to use.
The SW 201 inputs the GL input signal selected by this setting information to the GENLOCK & SG section 202, and outputs a synchronization signal synchronized with this. G in IST mode
A stable synchronous output is obtained by using the highly stable crystal generator output inside the ENLOCK & SG202 as a clock. The general method of using the sync signal generator is to use the GL
The SC signal is input and a highly stable sync signal is obtained. However, in an emergency, it is necessary to synchronously couple to the GL / VBS signal (BB signal in the office, color bar signal, etc.). In this case, in the prior art, when this need occurs, the switching of the GL / SC → GL / VBS signal input is manual, which is time-consuming and unresponsive.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to automate input switching, which is a drawback of the prior art, so that instantaneous switching can be handled.

[0004]

In order to achieve the above object, the present invention fixes the priority order of multiple inputs (GL / VBS, GL / SC) and simultaneously inputs GL / VBS and GL / SC. If it is present, synchronously connect to GL / VBS, GL / V
In the case of either BS or GLSC, the input signal is synchronously coupled and the input signal is automatically switched by the detection function for determining the presence or absence of the input signal.

[0005]

Now, when the GL / VBS signal is urgently input to the synchronizing signal generator which is synchronously coupled to the SC signal of the Rb oscillator, the GL / VBS signal detecting circuit operates and the GL / VBS signal is instantaneously output. Is supplied to the synchronizing signal generator, the synchronous coupling from the SC signal of the Rb oscillator to the GL / VBS signal is automatically and quickly performed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention will be described below with reference to FIG. 101 is a switching unit, 102 is a synchronous coupling / synchronization signal generation unit, 103 is a GL / VBS signal detection unit, and 104 is G
L. This is an SC signal detector. When the GL / VBS signal is input, the GL / VBS is set by DETECT1 of 103.
Send a signal with a signal to the SW section of 101, and the SW output is G
Select L ・ VBS IN, input to 102, GL ・ V
It outputs a sync signal that is synchronously coupled to the BS. When only the GL / SC signals are input, similarly, a synchronization signal synchronously coupled to the GL / SC signals is output. GL / VBS and GL
・ When SC is input at the same time, it is synchronized with the GL / VBS signal. When neither GL / UBS nor GL / SC is present, a stable sync signal is generated from the crystal oscillator inside 102 (INT mode).

[0007]

According to the present invention, GL. VBS IN,
When there is an input signal of GL / SC IN, the priority is fixed and in order to make the synchronization signal generator easier to use, it automatically switches and enables instantaneous switching.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

 101 switching unit 102 synchronous coupling & signal generation unit 103, 104 detection unit 201 switching unit 202 synchronous coupling & signal generation unit 205 SW COWT unit

Claims (1)

[Claims] 1. A composite video synchronization signal (GL / VBS) or a subcarrier signal (S) output from a Rubidium oscillator.
The sync signal generator that is synchronously coupled to either of C) has a function of detecting the input of the GL / VBS signal and the SC signal, and when the GL / VBS signal and the SC signal are simultaneously input, the GL is automatically input. ． Synchronously coupled to VBS signal, G
When only one of L / VBS signal or SC signal input is input, it is automatically synchronized with the input signal, and when both GL, VBS signal and SC signal are not present, it is stable at the local oscillation. Multi-input sync signal generation method that outputs various sync signals.