KR920001996Y1 - Auto-switching circuit of multi-system tv - Google Patents

Abstract

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Description

Carrier Color Signal Delay Line and Color Synchronizer Circuit in Multi-System TV Receiver

1 is a circuit block diagram of the present invention.

* Explanation of symbols for main parts of the drawings

10: voice intermediate frequency discrimination circuit 11: vertical frequency discrimination circuit

12 gate integrated circuit 13 carrier color signal delay line

14: crystal synchronization oscillator

The present invention is a multi-system TV receiver capable of receiving all three types of TV signals such as PAL, B / G, N, and M. It is about a circuit.

In general, in the case of a multi-system TV receiver, the carrier color signal delay lines used for the PAL method have different vertical, horizontal frequencies, voice intermediate frequencies, and color carrier frequencies for each of the three B / G, N, and M systems. .

That is, as an example, the horizontal frequency is 15625 mega hertz in the B / G system and the N method, the M carrier uses 15734 mega Hertz, the color carrier frequency is 4,433618 mega Hertz in the B / G system N, The N method uses 3,575,611 mega hetz.

Therefore, the carrier color signal delay line used in the PAL method has to be selected according to the receiving method when the horizontal color and the color carrier frequency are all different from each other. do. In addition, since the carrier frequency of the color part according to each reception method (B / G, N, M) is different from each other, three crystal oscillators must be configured for the color synchronizer, and one of the three crystal oscillators is correctly selected according to the reception method. Should be.

The present invention is intended to automatically switch according to the signal method of receiving the carrier color signal delay line and the color synchronization circuit crystal oscillator in consideration of the difference between the vertical frequency and the voice intermediate frequency for each of the three signal methods. Hereinafter, the configuration in detail with reference to the accompanying drawings as follows.

As shown in FIG. 1, the voice intermediate frequency discrimination integrated circuit 10 has a 5, 5 megahertz B / G method, or 4,5 megabytes according to a method (B / G, N, M) received by the arm (PAL) method. The audio intermediate frequency input signals (A, B) of the Hertz N and M methods are applied, and the vertical frequency discrimination integrated circuit 11 receives 50 Hz (B / G, N) or 60 Hertz (M) vertical frequencies. The composite video signal C is applied, and the audio intermediate frequency discrimination voltage D determined from the audio intermediate frequency discrimination integrated circuit 10 and the vertical frequency discrimination determined from the vertical frequency discrimination integrated circuit 1 are determined. The voltage E is connected to the gate integrated circuit 12 having two inputs and three outputs, and the switching voltages F, G, and H of the B / G, N, and M methods outputted therefrom are delayed carrier color signals. And interconnected so as to be transmitted to the line 13 and the color synchronizer circuit crystal oscillator 14.

Referring to the operation and effect of the present invention configured as described above, first, vertical, horizontal frequency and voice intermediate frequency and color carrier and frequency according to B / G, N, M method for each received signal by the arm (PAL) method Is shown in Table 1.

TABLE 1

That is, as shown in FIG. 1, the voice intermediate frequency discrimination integrated circuit 10 includes a 4 and 5 megahertz voice intermediate frequency input signal A of N and M methods and a 5 and 5 megahertz voice intermediate signal of B and G methods. B) is applied. At this time, the voice intermediate frequency discrimination integrated circuit 10 discriminates the voice intermediate frequency input signal of each type by a built-in disk limiter, and when the 4, 5 megahertz voice intermediate frequency A of the N or M type is input, the " Low ", B / G 5, 5 Mega Hetz voice intermediate frequency (B) will output" high "when input.

In addition, the vertical frequency discrimination integrated circuit 11 receives a complex image signal C including the vertical frequency of each system output from the image intermediate frequency demodulator. At this time, the vertical frequency discrimination integrated circuit 11 counts the vertical frequency of the input image signal C, but when the 50 Hz vertical frequency of B / G and N type is input, it is " low " Will output "high".

That is, it is shown in Table 2 below.

TABLE 2

In this way, the gate intermediate such that the voice intermediate frequency discrimination voltage D and the vertical frequency discrimination voltage E of the voice intermediate frequency discrimination integrated circuit 10 and the vertical frequency discrimination integrated circuit 11 according to each signal system outputs 2 inputs and 3 outputs. Is applied to the circuit 12.

At the same time, in the gate integrated circuit 12, the output voltages D and E determined from the voice intermediate frequency discrimination integrated circuit 10 and the vertical frequency discrimination integrated circuit 11 are combined with each other. Output characteristics such as can obtain an output voltage corresponding to each signal system.

TABLE 3

That is, when the "high" signal of the voice intermediate frequency discrimination voltage D and the "low" signal of the vertical frequency discrimination voltage E are applied to the gate integrated circuit 12, the carrier color signal is thereby matched to the B / G method. The output voltage F " high ", which can switch the delay line 13 and the crystal oscillator 14 of the color synchronizer circuit, is output, and the color synchronizer corresponding to the B / G system among the three crystal oscillators (not shown) for the color synchronizer is output. The circuit crystal oscillator 14 is selected and the carrier color signal delay line 13 corresponding to the B / G system is selected from the three color signal delay lines (not shown).

In addition, when the "low" signal of the voice intermediate frequency discrimination voltage D and the "low" signal of the vertical frequency discrimination voltage E are applied to the gate integrated circuit 12 through the above process, this time corresponds to the N method. The switching voltage G " high " for selecting the carrier color signal delay line 13 and the crystal oscillator 14 of the color synchronizing circuit is outputted so that the N-method of the three crystal oscillators (not shown) for the color synchronizing is output. The color synchronization circuit crystal oscillator 14 is selected, and the carrier color signal delay line 13 corresponding to the N system is selected from the three color signal delay lines (not shown).

In addition, as described above, when the "low" signal of the voice intermediate frequency discrimination voltage D and the "high" signal of the vertical frequency discrimination voltage E are respectively applied to the gate integrated circuit 12, the carrier transfers the signal according to the M scheme. Color signal delay line 13 and color synchronizing circuit correction The switching voltage H "high" of the oscillator 14 is output to correct the color synchronizing circuit corresponding to the M system among the three crystal oscillators (not shown) for the color synchronizing. As the oscillator 14 is selected, a carrier color signal delay line 13 corresponding to the M system is selected among three color signal delay lines (not shown).

According to the present invention as described above, the crystal oscillator of the carrier color signal delay line and the color synchronizing circuit suitable for each B / G, N, M method is used by using the difference between the vertical frequency and the audio intermediate frequency of each method. It is a very useful design that can give the enhanced function of a multisystem TV set by allowing automatic selection switching.

Claims (1)

The voice intermediate frequency discrimination integrated circuit 10 has a 5, 5 megahertz or 4, 5 megahertz voice intermediate frequency input signal (A, according to the PAL method of receiving (B / G, N, M). B) is applied, and the video signal C of 50 Hz (B / G, N type) and 60 Hz (M type) is applied to the vertical frequency discrimination integrated circuit 11, and the audio intermediate frequency discrimination integrated circuit ( The audio intermediate frequency discrimination voltage D determined from 10) and the vertical frequency discrimination voltage E determined from the vertical frequency discrimination integrated circuit 11 are transmitted to the gate integrated circuit 12 having two inputs and three outputs. Interconnected so that B / G, N, and M switching voltages (F, G, H) are output from the carrier color delay line (13) and the color synchronization circuit crystal oscillator (14). Carrier color signal of multi-system TV receiver characterized by switching of carrier color signal delay line and crystal oscillator suitable for each B / G, N, M method Crystalline oscillator automatic switching circuit with delay line and color synchronization circuit.