KR0177666B1 - Rf modulation circuit by pal method - Google Patents

Abstract

The present invention relates to a high frequency modulated circuit (RF Modulate Circuit) such as a video tape recorder (VTR), a game machine in the PAL method, in particular, according to the broadcasting method such as B / G method, I method, D method, etc. The present invention relates to a high frequency modulation circuit for a PAL system that allows a user to easily tune to other voice carrier frequencies according to a broadcast method and to generate a TSG signal using the voice carrier frequency.

The present invention does not require a separate resonator or condenser for generating a TSG signal, and generates a TSG signal by dividing a voice carrier according to a broadcasting method and always providing a constant frequency to a TSG circuit, wherein the TSG signal is divided. Since it is produced at a frequency, an error of about +10 Hz exists for the oscillation frequency, 5.5 MHz by the original tank circuit and the oscillator, and the error is divided at the same time as the oscillation frequency, so that the error is reduced to about 1/20. The TSG signal is more precise.

Description

High Frequency Modulation Circuit for Arm

The present invention relates to a high frequency modulated circuit (RF Modulate Circuit) such as a video tape recorder (VTR), a game machine in the PAL method, in particular, according to the broadcasting method such as B / G method, I method, D method, etc. The present invention relates to a high frequency modulation circuit for the arm (PAL) system that allows the user to easily tune to other voice carrier frequencies and to generate a TSG signal using the voice carrier frequency.

In general, the television broadcasting system is known NTSC system of the United States, Japan, Korea, etc., PAL system and SECAM system of Europe. The PAL system adopted in Europe also varies according to the region such as the B / G system, the I system, the D system, etc., and the voice carrier frequency varies from 5.5 MHz, 6.0 MHz, 6.5 MHz, etc., depending on the broadcasting system.

FIG. 1 is a block diagram of a conventional arm type high frequency modulation circuit. Referring to FIG. 1, a clamp for fixing a sync tip potential of a video signal Vin, which is a composite video signal reproduced by a video tape recorder or a game machine, to a predetermined level is shown in FIG. And a circuit unit (1), which is mixed in the next mixer (5) through a switching unit (3) for selecting and outputting the video signal and the TSG signal, and is output to the television set through the high frequency amplifier (6). The audio signal Ain is also frequency modulated by the next frequency modulator 4 through the audio amplifier 2, mixed by the mixer 5, and output to the television set through the high frequency amplifier 6.

The conventional high frequency modulation circuit has a cumbersome problem of manually operating a mechanical switch (SW1) installed at the rear end of a set in order to match different voice carrier frequencies according to the broadcasting method in the PAL method.

In addition, the general consumer rarely uses it, but the cost increases due to the separate condenser, expensive SAW resonator, and oscillator circuit for generating the TSG signal for the purpose of testing the set during the production stage. There was a problem.

The present invention has been made to solve the above problems, and therefore, an object of the present invention is to generate a TSG signal using a voice carrier frequency without using a separate resonant element, a capacitor, an oscillator, and the like. To provide a high frequency modulation circuit for.

1 is a block diagram of a conventional high frequency modulation circuit.

2 is a block diagram of a high frequency modulation circuit according to the present invention.

* Explanation of symbols for main parts of the drawings

20: tank circuit 31 ~ 33: voice carrier generator

34: oscillator 40: control unit

50: electronic switch unit 60: divider

70: TSG circuit portion 81: clamp circuit portion

82: switching unit 83: audio amplifier

84: frequency modulator 85: mixer

86: high frequency amplifier

As a technical means for achieving the above object of the present invention, the circuit of the present invention includes a TSG circuit section for generating a TSG signal based on an input frequency, a tank circuit section constituting a voice carrier resonant circuit according to a broadcasting method; A voice carrier oscillator for oscillating a voice carrier by the tank circuit unit, a clamp circuit unit for fixing a potential of a video signal at a constant level, an audio amplifier unit for amplifying an audio signal, and the audio signal according to an output signal of the audio amplifier unit. A frequency modulator for frequency modulating a voice carrier from a carrier oscillator, a mixer for mixing and outputting an output signal of the frequency modulator and an output signal of the clamp circuit or a TSG circuit at an oscillation frequency of an oscillator, and an output signal of the mixer A high frequency amplifier for amplifying a signal and selecting the voice carrier according to switching control In comprising an electronic switch which is switched so as to provide parts of the frequency modulation unit sides edible high frequency modulation circuit, it decodes the channel selection signal from the external control unit that performs switching control with the main control minutes; A divider which divides a voice carrier input from the voice carrier oscillator according to the division control of the controller and always provides a constant frequency to the TSG circuit unit; A switching unit for switching the signal output from the clamp circuit unit and the signal output from the TSG circuit unit; Characterized in having a.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a block diagram of a high frequency modulation circuit according to the present invention. Referring to FIG. 2, 20 is a tank circuit section, which is a voice carrier resonant circuit according to a broadcasting method, and includes a first tank C1 and L1 and a second tank. (22, L2) and the third tank (C3, L3). 31 to 33 are sound wave carrier oscillators, which oscillate the resonant frequency from the tank circuit unit 20. 40 denotes a control unit, which decodes the tuning signals S1 and S2 from the outside to perform switching control and division control. 50 is an electronic switch unit, which is switched to provide the voice carriers fc1, fc2, and fc3 to the frequency modulator and the divider, respectively, under the control of the controller 40.

60 is a divider, which divides the voice carriers fc1, fc2 and fc3 inputted from the voice carrier oscillator by the division ratios 1/22, 1/24 and 1/26 under the control of the controller 40. 70 is a TSG (Test Signal Generator) circuit unit, which outputs a TSG signal at a frequency output from the divider 60.

81 is a clamp circuit, which fixes the potential of the video signal Vin sink tip, which is a composite video signal, at a constant level. 82 is a switching unit, which switches and outputs a signal output from the clamp circuit unit 81 and a signal output from the TSG circuit unit 70 according to external control. 83 is an audio amplifier, which amplifies the audio signal Ain. 84 denotes a frequency modulator, which modulates the voice carrier wave selected by the electronic switch unit 50 as an output signal of the audio amplifier 83. 85 is a mixer, which mixes the output signal of the frequency modulator 84 and the output signal of the switching unit 82 with the oscillation frequency of the oscillator 34 to output a high frequency RF. 86 is a high frequency amplification part, which amplifies and outputs the output signal of the mixer 85.

Hereinafter, the operation and effect according to the present invention will be described based on the accompanying drawings.

2 and 3, first, the control unit 40 decodes the tuning signals S1 and S2 input to the control unit 40 to selectively select the switches SW1 to SW3 in the electronic switch unit 50. For example, when S1 and S2 are 0, the switch SW1 in the electronic switch unit 50 is turned on, and when 1, the switch SW2 in the electronic switch unit 50 is turned on. 10, the switch SW3 in the electronic switch section 50 is turned on.

On the other hand, in the tank circuit 20, the oscillator is resonated at 5.5 MHz in the first tanks C1 and L1, 6.0 MHz in the second tanks C2 and L2, and 6.5 MHz in the third tanks C3 and L3. Oscillates at 31 to 33 and is provided as a voice carrier to the frequency modulator 84 selectively for the operation of the electronic switch unit 50. For example, when the signals S1 and S2 are detected as 0, the electronic switch When the switch SW1 of the unit 50 is turned on, the voice carrier 5.5 MHz is provided to the frequency modulator 84 and the divider 60. When 1 is detected, the voice carrier is 6.0 MHz. The voice carrier 6.5 MHz is provided to the frequency modulator 84 and the divider 60, respectively.

The tuning signals S1 and S2 input to the controller 40 are control signals by an external microcomputer or a level signal by an external mechanical switch.

In addition, the divider 60 divides 1/22 when the voice carrier 5.5 MHz is input, 1/24 divides when 6.0 MHz is input, and 1/26 divides when 6.5 MHz is input under the control of the controller 40. As a result, under the control of the controller 40, the divider 60 always supplies 250 MHz to the TSG circuit unit 70. The TSG circuit unit 70 generates and outputs a TSG signal based on the frequency provided from the divider 60.

On the other hand, the video signal Vin fixes the potential of the sink tip of the video signal at a constant level in the clamp circuit unit 81, and selectively mixes one of the video signal or the TSG signal by switching of the switching unit 82. Output to (85). In addition, the audio signal Ain is amplified to a predetermined level by the audio amplifier 83, and then input to the high frequency modulator 84. In this high frequency modulator 84, a voice carrier provided as described above is used as an audio signal. Modulate and output to mixer 85.

The mixer 85 mixes one of the input video signal or the TSG signal and the modulated audio signal at the oscillation frequency of the oscillator 34, and outputs each of the mixed signals by the high frequency amplifier 86. Is then amplified to a certain level and then output to another set, such as a television set.

As described above, the present invention does not require a separate resonator or a capacitor for generating a TSG signal, and generates a TSG signal by dividing a voice carrier according to a broadcasting method and always providing a constant frequency to a TSG circuit. Since the signal is generated by dividing the voice carrier, there is an error of about +10 Hz with respect to the oscillation frequency of the original tank circuit and the oscillator. The error is also divided with the oscillation frequency, so the error is reduced to about 1/20. As a result, the TSG signal is more precisely generated.

According to the present invention as described above, it is possible to easily tune the different voice carrier frequency in accordance with the broadcast method according to the broadcasting method such as B / G system, I method, D method among the PAL system, as well as the voice carrier frequency By generating the TSG signal by using, there is an excellent effect that can generate a more precise TSG signal without the need for a separate resonator or capacitor for generating the TSG signal.

Claims (1)

A TSG circuit section 70 for generating a TSG signal based on the input frequency, a tank circuit section 20 constituting a voice carrier resonant circuit according to a broadcasting method, and a voice for oscillating a voice carrier by the tank circuit section 20. Carrier oscillators 31 to 33, a clamp circuit section 81 for fixing the potential of the video signal Vin at a constant level, an audio amplifier section 83 for amplifying the audio signal Vin, and the audio amplifier section ( A frequency modulator 84 for frequency modulating the voice carriers from the voice carrier oscillators 31 to 33, an output signal of the frequency modulator 84, and the clamp circuit 81 or the like. A mixer 85 for mixing and outputting the output signal of the TSG circuit unit 70 at the oscillation frequency of the oscillator 34, a high frequency amplifier 86 for amplifying the output signal of the mixer 85, and switching control. According to the voice carrier selectively frequency modulator ( 84. An arm type high frequency modulation circuit comprising an electronic switch unit 50 switched to provide a control device, comprising: a control unit 40 for performing a switching control and a division control by decoding a tuning signal from outside; A divider 60 which divides the voice carrier input from the voice carrier oscillator according to the division control of the controller 40 and always provides a constant frequency to the TSG circuit unit 70; And a switching unit (82) for switching the signal output from the clamp circuit unit (81) and the signal output from the TSG circuit unit (70).