JPH0236672A - Synchronizing signal generating circuit - Google Patents

Abstract

PURPOSE:To switch the synchronizing system of a synchronizing signal output automatically by providing a synchronizing system detection section to an external synchronizing signal input section so as to detect the synchronizing system. CONSTITUTION:A synchronizing system detection section 3 detects the state of number of horizontal scanning lines, number of fields and the mode of a color synchronizing signal so as to detect which of the TV standard systems is employed and gives its detection output (b) to a synchronizing signal generating section 2 and a display signal output terminal 4. Then the synchronizing signal generating section 2 generates the synchronizing signal of the same TV standard system as that detected by the synchronizing system detection section 3 in response to the detection output (b) of the synchronizing system detection section 3 and outputs a synchronizing signal (c) synchronously with an external synchronizing signal (a). Thus, the circuit is in operation in the mode generating automatically the synchronizing signal of the same synchronizing system as the inputted external synchronizing signal.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a video signal generator that can selectively generate video signals of two or more different television (TV) standard formats and has an external synchronization function. The present invention relates to a synchronization signal generation circuit suitable for use, and particularly to a synchronization signal generation circuit that generates a synchronization signal of an arbitrarily selected TV standard system.

[Summary of the invention]

Regarding a synchronization signal generation circuit suitable for use in a video signal generator capable of generating video signals of two or more different television standard formats and having an external synchronization function, the external synchronization signal input section is provided with a synchronization method detection section. A device that automatically switches the synchronization method of the synchronization signal output by detecting the synchronization method.

[Prior Art] Video signal generators used for adjusting and testing video equipment such as television receivers and VTRs generate various test patterns of two or more types of television (TV) standard systems, composite synchronization signals, etc. There are now many devices that can output the video signal by switching it with a switch. For example, NTS
It is now possible to switch and output video signals of C format with 525 horizontal scanning lines and 60 fields/sec and PAL and SECAM format video signals with 625 horizontal scanning lines and 50 fields/sec. It has become. Furthermore, an input terminal for a synchronization signal generated by a reference signal generator or the like inside the broadcasting station, that is, an external synchronization signal, is provided, and external synchronization is applied to synchronize the signal generated inside the video signal generator with the external synchronization signal. This is often the case. However, if the TV standard format is switched while the video signal generator is in use with an external synchronization signal input, the external synchronization will also be lost, and normally the external synchronization signal must also be replaced. Here, the synchronization signal is a general term for signals that serve as a timing reference for television signals, such as composite synchronization signals and color burst signals.

As a result, errors in the output signal (output of signals that are not externally synchronized, etc.) may occur due to incorrect operation of the video signal generator, or
A time loss occurs when switching the TV standard system.

A similar problem also occurred when a video monitor of a type capable of externally synchronizing images of two or more types of TV standards was used.

(Problems to be Solved by the Invention) An object of the present invention is to obtain a synchronization signal generation circuit suitable for use in a video signal generator, which solves the problems described in the prior art.

[Means to solve the problem]

In the present invention, two or more types of television (TV)
In a synchronization signal generation circuit having a synchronization signal generation section capable of selectively controlling and outputting a standard synchronization signal and an external synchronization signal input terminal, determining the synchronization signal format of an external synchronization signal input from the input terminal. The detection output of the detection unit is input to the synchronization signal generation unit to control the synchronization signal system of the synchronization signal generated by the synchronization signal generation unit, and the detected TV standard is controlled by the detection output of the detection unit. A synchronization signal generation circuit is characterized in that it outputs two synchronization signals.

Alternatively, the method includes a coincidence detection section that detects whether or not the synchronization signal format of the manually selected television standard format matches the synchronization signal format detected by the detection section, and the coincidence detection section detects the coincidence. The synchronizing signal generating circuit is characterized in that the synchronizing signal generating section outputs a synchronizing signal of the matched synchronizing signal system only when the synchronizing signal generating section matches the synchronizing signal method.

Alternatively, multiple external synchronization signal input terminals are provided, and in conjunction with the selection of the synchronization signal method for outputting the synchronization signal from the synchronization signal generator, the external synchronization signal input terminal of the same method as the selected synchronization signal method is connected. A synchronous selection circuit may also be provided.

[Effect]

Since the synchronization signal generation circuit of the present invention includes a synchronization method detection section for an external synchronization signal, it can be operated in a mode in which a synchronization signal of the same synchronization method as the input external synchronization signal is automatically generated.

Furthermore, when you manually select the TV standard method,
It is also possible to operate in a mode in which the synchronization signal generator generates the synchronization signal only when the synchronization method matches the external synchronization signal input from the external synchronization signal input terminal.

When multiple external synchronization input terminals are provided in manual mode, the external synchronization signal and the synchronization signal output from the synchronization signal generator can be simultaneously converted into signals of the same synchronization method by simply operating the TV standard selection switch, etc. You can also switch.

〔Example〕

FIG. 1 shows a synchronization signal generation circuit according to an embodiment, which will first be explained according to the block diagram of the automatic external synchronization mode shown in FIG. 1(a).

External synchronization signal a manually input from external synchronization signal input terminal 1
is sent to the synchronization signal generation section 2 and the synchronization method detection section 3. As will be explained in detail later, the synchronization method detection unit 3 detects the number of horizontal scanning lines, the number of fields, and the aspect of the color synchronization signal to
It detects which standard method is used, such as NTSClPAL, and sends the detected output to the synchronization signal generator 2 and the TV.
Display signal output terminal 4 for displaying standard method selection status
I am sending it to

In response to the detection output of the synchronization method detection section 3, the synchronization signal generation section 2 generates a synchronization signal of the same TV standard method as that detected by the synchronization method detection section 3, and synchronizes it with the external synchronization signal a. A synchronizing signal C is output. The output synchronization signal C is sent to a video signal generation block that generates test signals such as a pattern generator.

FIG. 1(b) is a block diagram when switching to semi-manual mode, and new TV standard system selection input terminal 5,
It includes a synchronization method detection section 3B, a coincidence detection section 6, an external synchronization signal switch 7, and the like.

From the input terminal 5, either a code indicating the selected TV standard system can be input (by pressing a selection button, etc.), or a signal of the selected TV standard system can be input. The configuration is arbitrary, just by matching the configuration of the b input section of the synchronizing signal generating section 2. The input terminal 5
The input signal from the external synchronization signal passes through the synchronization method detection section 3B and is compared with the output of the synchronization method detection section 3A of the external synchronization signal in the coincidence detection section 6. By outputting the comparison result, the external synchronizing signal switch 7 provided between the external synchronizing signal input terminal +1 and the synchronizing signal generating section 2 is turned ON10FF. According to the 0N10FF, if the synchronization methods of the input of input terminal 1 and the input of input terminal 5 match as a result of the comparison, the synchronization signal C is output, and if they do not match, the output of the synchronization signal C is stopped. I am planning to do so. This can prevent outputting a signal that is not synchronized with the external synchronization signal or outputting a signal of a different system.

FIG. 2 is a block diagram showing details of the synchronization method detection section of the embodiment, which is composed of a horizontal and vertical synchronization method detection section (a) and a color synchronization method detection section (b). First, the horizontal/vertical synchronization method detection section (a) includes a synchronization separator 32, a line counter 33, a detection 34, a field counter 35,
It consists of a gate 36 and the like.

First, a synchronizing separator 32 separates a horizontal synchronizing signal and a vertical synchronizing signal, and a line counter 33 counts the number of horizontal scanning lines. (2) The field counter 35 counts the number of fields from the vertical synchronization signal extracted by the detection 34. The gate 36 outputs an output indicating the number of horizontal and vertical scans, such as 525 horizontal lines/60 fields, and sends it to the burst detector 39 of the color synchronization detection section (b). The color synchronization method detection section (b) includes a timing generator 37 that generates a timing signal according to the horizontal and vertical synchronization signals sent from the horizontal and vertical synchronization method detection section (a), and an input signal input from the input terminal 31. It is composed of a burst gate 38 that extracts a burst signal (color synchronization signal) and a burst detector 39 that detects the burst signal.
8 and the burst detector 39 are controlled by a timing signal sent from a timing generator 37. The burst detector 39 is equipped with detection circuits of a plurality of methods so as to be able to detect burst signals of a plurality of TV standard methods. selected. Furthermore, the horizontal and vertical synchronization signals and the burst signal are synchronized by the timing signal output from the timing generator 37. Furthermore, the burst detector 39 sequentially adjusts the color synchronization mode (color carrier frequency, sequential or simultaneous, whether the color signal phase changes alternately, etc.) with reference values preset in accordance with each TV standard system. In comparison, NTSC, PAL
, SECAM.

It is determined which TV standard system, such as PALM, is used, and the determination result is output. It is convenient to output the output using a digital code such as an hour wheel. In particular, the synchronization signal generator 2
When controlling the signal generation mode using a digital circuit,
This is suitable when it is desired to input the input signal of the input terminal 5 from a remote control commander. Figure 1 (b
) when the input from the input terminal 5 is a digital code, it passes through the dotted line route, and the synchronization method detection section 3B is not required, and when the input from the input terminal 5 in FIG. 1(b) is a TV signal, it passes the solid line route. go through the route of Here, the synchronization method detection unit 3B
The same circuit as the synchronization method detection section 3A may be provided separately, or one circuit may be used in a time-division manner.

FIG. 3 is a block diagram of a synchronization signal generation circuit according to another embodiment, which includes a plurality of external synchronization input terminals 11A, 11B, 11C-.
---, TV standard system selection input terminal 12
A code (digital code, voltage code, etc.) indicating an arbitrarily selected TV standard method to obtain a synchronization signal output from
When input, the synchronization signal generator 2 is switched to the arbitrarily selected synchronization method, and at the same time, the external synchronization selection circuit 2 also selects the external synchronization input terminals IIA, IIB, 11C-.
・The configuration is such that only the terminal to which an external synchronization signal of a synchronization method arbitrarily selected from - is input is connected.

This can prevent an arbitrarily selected synchronization signal from being output without being externally synchronized. In addition, input terminal 1
It is also possible to select a synchronization signal method by inputting a TV signal of an arbitrary TV standard method to the external synchronization selection circuit 13 by including a synchronization method detection section 3B.

〔Effect of the invention〕

By implementing the present invention, it is possible to automatically generate a synchronization signal in accordance with the synchronization signal method of the external synchronization signal, and even if the TV standard method is manually selected, the external synchronization signal can be automatically synchronized with the arbitrarily selected TV standard method. A synchronization signal generation circuit that outputs a synchronization signal only when the synchronization signal formats of the signals match can be obtained. As a result, it is possible to prevent erroneous copying, such as when an external synchronization is intended to be applied but in fact it is not, the trouble of switching the TV standard system is saved, and a synchronization signal generation circuit that can also be switched by remote control can be obtained.

The synchronization signal generation circuit is particularly suitable for use in a video signal generator that generates test patterns and other video signals of two or more TV standards; It is also suitable for use in monitor devices that display images.

A block diagram of the manual mode is shown.

FIG. 2 is a detailed block diagram of the synchronization method detection section of the embodiment.

FIG. 3 shows a synchronizing signal generating circuit according to another embodiment.

■・−・−・−・−・−External synchronization signal input terminal 2−・−
··········································································································································································································· are, ,······························································ are,.,synchronization method, detecting unit, 5,,.
・−・−・−・−・−TV standard method selection input terminal 6−・
·················································································································································································································· ( (b) -----------Color synchronization method detection section

[Brief explanation of the drawing]

FIG. 1 shows the synchronization signal generation circuit of the embodiment, (a) is a block diagram of automatic external synchronization mode, and (b) is a block diagram of (a) automatic external synchronization mode. Tool month 4
Figure 2 is a detailed block diagram of the synchronized fertilization section of the example of the 1-Rin production.

Claims (1)

[Scope of Claims] 1. In a synchronization signal generation circuit having a synchronization signal generation section capable of selectively controlling and outputting synchronization signals of a plurality of television standard systems and an external synchronization signal input terminal, the synchronization signal is input from the input terminal. a synchronization method detection section that determines the synchronization signal method of the external synchronization signal generated, and the detection output of the detection section is input to the synchronization signal generation section, thereby detecting the synchronization signal generated by the synchronization signal generation section. A synchronization signal generation circuit, wherein a synchronization signal method is controlled and outputs a synchronization signal of the detected synchronization signal method. 2. In a synchronization signal generation circuit having a synchronization signal generation section capable of selectively controlling and outputting synchronization signals of a plurality of television standard systems and an external synchronization signal input terminal, the external synchronization signal input from the input terminal is The apparatus includes a synchronization method detection section that determines a synchronization signal method, and a coincidence detection section that detects whether or not the synchronization signal method of the manually selected television standard format matches the synchronization signal method detected by the detection section. . A synchronization signal generation circuit, characterized in that only when the coincidence detection section detects the coincidence, the synchronization signal generation section outputs a synchronization signal of the matched synchronization signal system.