JPS6239995A - Television signal processor - Google Patents

Abstract

PURPOSE:To discriminate an NTSC system or a PAL system by providing a synchronous signal separating means for separating a synchronous signal including a horizontal synchronous pulse, a separating means for separating the horizontal synchronous pulse from the separated synchronous signal, and a counting means. CONSTITUTION:A horizontal synchronous pulse separating circuit 3 extracts a pulse train of the same cycle and a horizontal synchronous pulse HP from an inputted synchronous signal and outputs. A pulse detecting circuit 4 extracts a fall pulse which does not coincide with a fall timing of the horizontal synchronous pulse from an output of a fall detecting circuit 2 and outputs a pulse (d). A vertical synchronous signal separating circuit 5 separates a vertical synchronous signal falling only during a period in which a vertical synchronous pulse exists from the synchronous signal. A counter 6 counts the number of pulses in one frame under a control of the vertical synchronous signal. If the input signal is an NTSC signal, an output n1 of the counter 6 is 18 and if the input signal is a PAL signal, the output n1 of the counter 6 is 15.

Description

[Detailed Description of the Invention] [Summary] The number of synchronization pulses other than horizontal synchronization pulses in a television signal is counted over a predetermined period of time equal to or longer than the field, and based on the counted value, it is determined whether the signal is an NTSC signal or a PAL signal. Television signal processing device for discrimination.

[Industrial application field]

In the present invention, the received signal is NTSC (National
Te1e-vision System Comm1t
The present invention relates to a television signal processing device that easily distinguishes between a PΔI− (r'hase 8 Iter ation by Line) signal and a PΔI− (r'hase 8 Iter ation by Line) signal, and in particular, a P A 1.
DP CM (Differential Pu1
The present invention relates to a television signal processing device in the SE Code Modulation system.

When transmitting an NTSC television signal (hereinafter referred to as TV signal), which is used in Japan, to a country which uses the PAL system, such as between West Germany and other countries, by satellite relay, etc., the receiving side receives the input signal. It is necessary to determine whether the data is based on the NTSC system or the PAL system.

Conventionally, the received TV signal was in the NTSC format.
There was no known method to easily identify one-sided types.

[Purpose of the invention]

The purpose of the present invention is to determine whether the received TV signal is an NTSC signal or a PA
An object of the present invention is to provide a television signal processing device that can relatively easily determine whether an L signal is an L signal or not.

[Structure of the invention]

What is provided by the present invention is a synchronization signal separating means for separating a synchronization signal including a horizontal synchronization pulse from a television signal having a time longer than the time of at least one field;
Separating means for separating horizontal synchronizing pulses from the synchronizing signal separated by the synchronizing signal separating means; and counting means for counting pulses other than the horizontal synchronizing pulses in the synchronizing signal separated by the synchronizing signal separating means. Depending on the count value of the means, the television signal is an NTSC signal or a PAL signal.
This is a television signal processing device that determines whether a signal is present or not.

[For production]

Since the number of equal pulses and vertical synchronization pulses inserted between horizontal synchronization pulses in a television signal differs between the NTSC system and the PAL system, By counting the number of pulses, it is possible to determine whether the system is an NTSC system or a PAL system.

〔Example〕

Figure 3 is a waveform diagram of a TV signal according to the well-known NTSC system.
FIG. 4 is a waveform diagram of a TV signal according to the well-known I) AL system.

First, an NTSC TV signal will be explained with reference to FIG. FIG. 3(a) shows an odd field TV signal in interlaced scanning, and FIG. 3(g)) shows an even field TV signal. The scanning line numbers of the odd field V are 1-261 and 524, 525, and the scanning line numbers of the even field are 262-523. In both fields, an equalization pulse E1 is inserted before and after the vertical synchronization pulse v1 at the end of one video, followed by a horizontal synchronization pulse HP1. Horizontal sync pulse HPI cycle! UI H+ is ■11=63.555 ps,
The pulse width is 0.075 H.

The period of the equalization pulse E is 0.5H, and the pulse width is 0.5H.
04T(,.Vertical synchronization pulse ■1 period is 0,5
H, and the pulse width is 0.43H.

There are 6 equal 4W pulses in the 3■]1 period before the vertical sync pulse, and 6 in the arr+ period after it, and 6 vertical sync pulses in the 31(,) period. It can be seen that among the pulses and vertical synchronizing pulses, the number of remaining falling pulses excluding the pulse falling at the same timing as the horizontal synchronizing pulse is eight in the odd field and the even field.

Next, according to FIG. 4, P A 1. , the TV signal of the system will be explained. One frame of PAL TV signal is 4
It consists of two fields, as shown in Figure 3 (al to (d)).
respectively indicate the TV signals of the ■th field, the first field, the ■th field, and the ■th field. The scanning line numbers of the first field are 621 to 623 and 1 to 307, and the scanning line number of the second field is 3.
08 to 620, and the scanning line number of the ■th field is 6.
21 to 625 and 1 to 307, and the scanning line numbers of the second field are 308 to 620. For each field, before and after the vertical sync pulse ■2 at the end of one image,
Equalization pulse E2 is also inserted, followed by horizontal synchronization pulse I (P□.Horizontal synchronization pulse H,
, ) The period H2 is H,=64 μs. The period of equalization pulse 2 and vertical synchronization pulse 2 is 0.5H2, and the pulse widths are 0.037H2 and 0.4H2, respectively.
27 H□.

In the PAL system, the equalization pulse is 2.0 seconds before the vertical synchronization pulse.
There are five vertical synchronizing pulses v2 in a period of 5 Hz, five in a subsequent period of 2.5 H2, and five vertical synchronizing pulses v2 in a period of 2.5 H2. Among these equal six pulses and vertical synchronization pulses, the number of falling pulses remaining after excluding the pulse that falls at the same timing as the horizontal synchronization pulse is 8 in the first field and the It can be seen that there are 7 pieces each in the field and the ① field.

The present invention was made by paying attention to the fact that the numbers of equalization pulses and vertical synchronization pulses are different between the NTSC system and the PAL system as described above.

FIG. 1 is a block diagram showing a television signal processing device according to an embodiment of the present invention, and FIG. 2 is a signal waveform diagram of each part when an NTSC signal is input to the device shown in FIG. In FIGS. 1 and 2, the input signal NTSC signal is processed by the same IU1 signal separation circuit 1 as an equal pulse E1.
, Vertical sync pulse■.

and a synchronization signal including the horizontal synchronization pulse HPI (Fig. 2a)
) is separated and input to the falling edge detection circuit 2 and the horizontal synchronizing pulse separation circuit 3. The falling edge detection circuit 2 detects the falling edge of the input synchronizing signal and generates the pulse shown in FIG. The horizontal synchronizing pulse separation circuit 3 extracts a pulse train shown in FIG. 2C having the same period as the horizontal synchronizing pulse H6 from the input synchronizing signal and outputs it. The pulse detection circuit 4 extracts a falling pulse that does not match the falling timing of the horizontal synchronizing pulse from the output of the falling detection circuit 2 (FIG. 2b), and outputs the pulse shown in FIG. 2d. The vertical synchronization signal separation circuit 5 separates the vertical interval jfJl from the synchronization signal shown in FIG. 2a.
The vertical synchronizing signal shown in FIG. 2e, which falls only during the period when the pulse exists, is separated. The counter 6 counts the number of pulses shown in FIG. 2d within one frame under the control of the vertical synchronization signal.

If the input signal is an NTSC signal, the output n of the counter 6,
is 18, and if the input signal is a PAT signal, the output n of the counter 6 is 15. Depending on the difference in n, it is possible to determine whether the input signal is an NTSC signal or a PAL signal.

In the above embodiments, the number of pulses within one frame is counted, but the number of pulses may be counted over any length of one field or more.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the NTSC It is possible to easily determine whether the signal is a PAL system signal or a PAL system signal.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a television signal processing device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a television signal processing device according to an embodiment of the invention.
FIG. 3 is a waveform diagram of a TV signal according to the well-known NTSC system, and FIG. 4 is a waveform diagram of a TV signal according to the well-known PAL system. DESCRIPTION OF SYMBOLS 1... Synchronization signal separation circuit, 2... Fall detection circuit, 3... Horizontal synchronization pulse separation circuit, 4... Pulse detection circuit, 5... Vertical synchronization signal separation circuit, 6... counter.

Claims (1)

[Claims] (1) Synchronization signal separation means for separating a synchronization signal including a horizontal synchronization pulse from a television signal having a time longer than the time of at least one field; separating the horizontal synchronization pulse from the synchronization signal separated by the synchronization signal separation means; separation means, and counting means for counting pulses other than the horizontal synchronization pulse in the synchronization signal separated by the synchronization signal separation means, and the television signal is determined to be NTSC based on the count value by the counting means.
A television signal processing device that determines whether a signal is a PAL signal or a PAL signal.