KR940003354A - TV type discrimination circuit - Google Patents

Abstract

The present invention relates to a television type discrimination circuit for switching a television reception state by discriminating a type of a received signal when receiving a mute type and an NTSC type television signal in different time zones. The determination is made by detecting the presence or absence of the frame pulse included in the. The television type discrimination circuit includes a frame pulse detection unit for receiving a television signal and detecting a frame pulse of a mute type, and counting in horizontal and vertical directions in synchronization with a system clock to enable a predetermined period at a specific point in the horizontal and vertical directions. A horizontal / vertical sync signal generator for outputting control frame pulses, and a discrimination signal generator for varying states depending on whether two signals inputted by inputting output signals of the frame pulse detector and the horizontal / vertical sync signal generator are inputted And a TV reception state to be switched to the output of the discrimination signal generator, and implemented by using a conventional muse signal processing circuit without adding extra hardware, which is complicated in configuration. The effect that can suppress price increase by being easy to do There is.

Description

TV type discrimination circuit

Since this is an open matter, no full text was included.

3 is a block diagram of a television system discrimination circuit according to the present invention;

4 is a detailed block diagram of the frame pulse detector of FIG. 3;

5 is a detailed block diagram of the horizontal / vertical synchronous signal generator of FIG.

Claims (8)

A frame pulse detector for receiving a television signal and detecting a frame pulse of a mute method; A horizontal / vertical synchronous signal generator for counting in the horizontal and vertical directions in synchronization with the system clock and outputting a control flame pulse that is enabled for a predetermined time at a specific point in the horizontal and vertical directions; And a discrimination signal generator for changing the state of the two signals inputted by inputting the output signals of the frame pulse detector and the horizontal / vertical synchronous signal generator. Television type discrimination circuit, characterized in that. The method of claim 1, wherein the determination signal generator is further configured to enable the output when the period during which the frame pulse is activated becomes active during the period during which the control frame pulse is active, A synchronization determining unit for switching the output to disable if the same operation does not occur; And the output signal of the horizontal / vertical synchronization signal generator is reset in response to the signal of the synchronization determining unit being disabled. 3. The control circuit according to claim 2, wherein the output of the frame pulse detection unit is input to its own clock terminal, and the control frame pulse which is the output of the horizontal / vertical synchronous signal generator is input to its own input terminal and the output of the synchronization determination unit is input. And a D-flip-flop for outputting a signal that is inputted to its negative-reset terminal and is active if it is a muse-type signal and otherwise non-active. 2. The apparatus of claim 1, wherein the frame pulse detection unit comprises: a correlation determination unit for generating a pulse that is activated for one clock by using the correlation of the frame pulses in a mute method; In order to prevent malfunctions caused by the existence of correlations such as frame pulses other than the muse method, a frame is inputted by outputting the correlation determining unit and outputting an active signal only when the output signal of the correlation determining unit is activated at a specific point. A television system discrimination circuit comprising a pulse mask section. The method of claim 4, wherein And the specific point is the 475th sample point of the second line of the television signals in the case where the output signal of the correlation determining unit is activated at the specific point in the frame pulse mask unit. 2. The apparatus of claim 1, wherein the horizontal / vertical synchronous signal generator comprises: a counter block for counting horizontal / vertical addresses; A comparison block configured to input an output of the count block to compare a specific reference value and output a signal that is activated during a period in which the reference value and the input values become the same value; And an internal pulse generator for outputting a pulse which is enabled for a predetermined period from an active point of time when the output of the comparison block is active. 7. The apparatus of claim 6, wherein the counter block comprises: a horizontal address counter for inputting a system clock and increasing the coefficient by the number of sample points in the line; And a vertical address counter which inputs the output of the horizontal address counter and ascends the number of lines in one field. The method of claim 6, wherein the comparison block compares the output of the horizontal address counter with a reference value indicating a specific position of a sample point on a line, and outputs an active signal when two values being compared are equal. A first comparator; A second comparator for comparing the output of the vertical address counter with a reference value indicating a specific position of a line in a field and outputting a signal that is activated when two values being compared are equal; And a logic gate for inputting the outputs of the first comparator and the second comparator and outputting a signal that is activated when two input signals are simultaneously activated. ※ Note: The disclosure is based on the initial application.