KR0115245Y1 - Pal/secam mode detecting circuit - Google Patents

Abstract

The present invention relates to a PAL / SECAM broadcast signal discrimination circuit for discriminating whether a received broadcast signal is a PAL or SECAM broadcast signal. Conventionally, a burst signal of a PAL method and an ID of a SECAM method are used by using a burst gate pulse signal. Detects pulse signal and processes detected burst signal and ID pulse signal by frequency / voltage converter and level converter to determine whether it is PAL or SECAM broadcast signal. Since it is necessary to discriminate whether the broadcast signal is of the type, the discriminating means must be very precise, and error occurs a lot, thereby reducing the reliability of the product.

The present invention converts the period of the burst signal and the ID pulse signal into voltage by using the period of the burst signal of the PAL broadcast signal and the ID pulse signal of the SECAM broadcast signal different from each other, and converts the period of the burst signal and the ID pulse signal to the voltage and converts the PAL method to the converted voltage level. And the SECAM method broadcast signal is accurately identified to improve the reliability of the product without the occurrence of errors, and to improve the reliability of the product without the use of expensive precise discriminating means, and to avoid the use of expensive precise discriminating means. The production cost can be reduced.

Description

PAL / SECAM broadcasting signal discrimination circuit

1 is a broadcast signal discrimination circuit diagram of the present invention.

(A)-(f) of FIG. 2 are operation waveforms of each part of FIG.

* Explanation of symbols for main parts of the drawings

1: horizontal synchronous signal separating means 2: pulse generating means

2a: amplifier 2b: integrator

2c: inverter 3: signal separation means

4: voltage conversion means 4a: amplifier

4b: limiter 4c: integrator

5: Comparison and discrimination means

The present invention is to determine whether a received broadcast signal is a PAL or SECAM broadcast signal in various broadcast signal receivers such as a television receiver and a video cassette recorder capable of receiving both PAL and SECAM broadcast signals. The PAL / SECAM broadcast signal discrimination circuit is specifically designed for detecting PAL burst signals and SECAM ID pulse signals which are carried out within a blanking period of a video signal, and detecting the detected burst signals and ID pulse signals. It was processed by the converter and the level converter to determine whether it is PAL or SECAM broadcast signal.

That is, conventionally, in case of PAL broadcast signal with phase modulation, RY and BY signals are input for each horizontal line at a frequency of 4.43 MHz, and in case of SECAM broadcast signal, BY and 4.406 MHz have a frequency of 4.25 MHz. Since the RY signal having the frequency of is frequency-modulated and then alternately input to the horizontal line, when the signal of each horizontal line is converted into a voltage by using a frequency / voltage converter, the broadcast signal of the PAL method has no voltage difference. In the broadcast signal, a voltage difference is generated between the current horizontal line and the next horizontal line, and the broadcast signal of the PAL method and the SECAM method is determined using this voltage.

However, in the conventional technology as described above, it is necessary to determine whether the PAL and SECAM broadcast signals are caused by a weak voltage difference between each horizontal line, so that the discriminating means must be very precise, and error occurs so that the reliability of the product is reduced. There was a problem such as being.

The present invention has been made to solve the above-mentioned conventional problems, and the burst signal and the ID pulse signal using the periods of the burst signal of the PAL broadcast signal and the ID pulse signal of the SECAM broadcast signal are different from each other. The purpose of the present invention is to provide a PAL / SECAM broadcast signal discrimination circuit for converting a period of time to a voltage and accurately discriminating PAL and SECAM broadcast signals at the converted voltage level, which will be described in detail with reference to the accompanying drawings. .

FIG. 1 is a broadcast signal discrimination circuit diagram of the present invention, as shown therein, a horizontal synchronous signal separating means (1) for separating a horizontal synchronous signal from an input video signal (VS), and the horizontal synchronous signal separating means (1). A pulse generating means (2) which receives the horizontal synchronous signal separated from and generates a pulse signal corresponding to the horizontal blanking end, and is switched by the pulse signal of the pulse generating means (2) to burst in the input image signal (VS) Signal separating means (3) for separating the signal or ID pulse signal, and voltage converting means (4) for converting the burst signal or ID pulse signal separated by the signal separating means (3) into a voltage having a predetermined level corresponding to each signal. And a comparison and discriminating means (5) for outputting a signal for determining the PAL or SECAM method by comparing the voltage value converted by the voltage converting means (4) with the reference level of the broadcasting method discrimination.

The pulse generating means 2 includes an amplifier 2a for amplifying the horizontal synchronous signal separated by the horizontal synchronous signal separating means 1, and an integrator for integrating the horizontal synchronous signal amplified by the amplifier 2a ( 2b) and an inverter 2c for inverting the output signal of the integrator 2b and shaping it into a pulse signal, wherein the horizontal separating means 3 is turned on in accordance with the output signal of the inverter 2c. Or a transistor (Q1) and a resistor (R1) for turning off and separating the burst signal of the PAL method or the ID pulse signal of the SECAM method from the image signal VS, and the voltage conversion means (4) is the signal separation means ( An amplifier 6a for amplifying the burst signal or ID pulse signal separated in 3), a limiter 6b for adjusting the upper and lower limit levels of the signal amplified by the amplifier 6a, and an output of the limiter 6b. It consists of an integrator 6c that integrates the signal.

In the broadcast signal discrimination circuit of the present invention configured as described above, the horizontal synchronous signal separation means 1 separates the horizontal synchronous signal from the input video signal VS as shown in (a) of FIG. The signal is applied to the pulse generating means 2 to generate a pulse signal corresponding to the horizontal blanking period as shown in FIG.

That is, the horizontal synchronous signal separated by the horizontal synchronous signal separating means 1 is amplified in the amplifier 2a of the pulse generating means 2 as shown in (b) of FIG. 2, and the second in the integrator 2b. Since it is integrated as shown in (c) of FIG. 3 and input to the inverter 2c, the inverter 2c inverts and waveforms the integrated signal as shown in (d) of FIG. Is applied to the base of the transistor Q1.

Then, the transistor Q1 is turned on and off in accordance with the output signal of the inverter 2c, and when the video signal VS is a PAL broadcast signal, a burst carried in the blanking period as shown in FIG. When the signal is separated and the video signal VS is a SECAM broadcasting signal, the ID pulse signal carried in the blanking period is separated and output as shown in FIG.

In this way, the burst signal and the ID pulse signal which are separated and output by the signal separating means 3 are inputted to the voltage converting means 4 and converted into voltages having a level corresponding to each signal, and the voltage values are compared and discriminated. 5) is inputted to the reference level of the broadcast method discrimination to output the discrimination signal of the PAL method and SECAM method.

That is, a burst signal or an ID pulse signal such as (e) or (bar) of FIG. 2 input to the voltage converting means 4 from the signal separating means 3 is amplified by the amplifier 4a, and the amplified signal is a limiter. The upper and lower limit levels are shaped at 4b, and the signal passing through the limiter 4b is integrated at the integrator 4c and input from the comparing and discriminating means 5, and the comparing and discriminating means 5 is an integrator 4c. PAL and SECAM discrimination signals are output at the level of the output signal.

That is, in the case of PAL broadcast signal, the burst signal period in the blanking period of the video signal is short, so that the output voltage of the integrator 4c is low, and in the case of SECAM broadcast signal, the ID pulse carried in the blanking period of the video signal. Since the signal period is long, the PAL and SECAM broadcast signals are discriminated by comparing the output voltage of the integrator 4c with a voltage of a predetermined reference level.

As described in detail above, the present invention converts the period of the burst signal and the ID pulse signal into a voltage by using a period in which the burst signal of the PAL broadcast signal and the ID pulse signal of the SECAM broadcast signal are different from each other. By accurately discriminating the PAL and SECAM broadcast signals at one voltage level, there is no error, which improves the reliability of the product and reduces the production cost of the product without requiring the use of expensive and precise discriminating means.

Claims (3)

A horizontal synchronous signal separating means (1) for separating the horizontal synchronous signal from the input image signal (VS) and the horizontal synchronous signal separated from the horizontal synchronous signal separating means (1) to receive a pulse signal corresponding to the horizontal blanking section. A pulse generating means (2) for generating a signal; and a signal separating means (3) for switching a burst signal or an ID pulse signal from an input video signal (VS) by switching by a pulse signal of the pulse generating means (2); A voltage converting means (4) for converting the burst signal or ID pulse signal separated by the signal separating means (3) into a voltage having a predetermined level corresponding to each signal, and a voltage value converted by the voltage converting means (4). A PAL / SECAM broadcast signal discrimination circuit comprising: a comparison and discriminating means (5) for outputting a signal for discriminating a PAL method or a SECAM method in comparison with a reference level of the method discrimination. 2. The pulse generating means (2) according to claim 1, wherein the pulse generating means (2) comprises: an amplifier (2a) for amplifying the horizontal synchronous signal separated by the horizontal synchronous signal separating means (1), and the horizontal synchronous signal amplified by the amplifier (2a). PAL / SECAM broadcast signal discrimination circuit comprising an integrator (2b) for integrating and an inverter (2c) for inverting the output signal of the integrator (2b) to form a pulse signal. 2. The voltage converting means (4) according to claim 1, wherein the voltage converting means (4) includes an amplifier (6a) for amplifying the burst signal or the ID pulse signal separated by the signal separating means (3), and an upper limit of the signal amplified by the amplifier (6a). And a limiter (6b) for adjusting the lower limit level, and an integrator (6c) for integrating the output signal of the limiter (6b).