KR0183943B1 - Apparatus of control method of voice broadcasting of rf modulator - Google Patents

Abstract

An apparatus for controlling an audio broadcasting system of an RF modulator for a multiple broadcasting system is disclosed. The apparatus comprises a video unit for clamping an image signal output from an image signal source and switching the image signal between the image mode and the test pattern signal generator mode, an audio unit for amplifying the audio signal output from the audio signal source, And a signal output from one of the broadcasting system control input terminals is input to a triple duty circuit to output a broadcasting system control signal for controlling three types of audio broadcasting systems, A logic unit for generating a signal generator signal and outputting it to an amplifier circuit of the audio unit; and a logic unit for amplitude-modulating the video signal output from the video unit and the audio signal output from the audio unit at a specific RF frequency, .

As described above, according to the present invention, since the audio broadcasting system can be controlled by one control pin and one control switch, cost reduction and ease of use can be improved by reducing the number of package pins and reducing external components.

Description

An audio broadcasting system control device of an RF modulator for a multi-broadcasting system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling an audio broadcasting system of an RF modulator for a multi-broadcasting system, and more particularly, To a voice broadcasting system control apparatus of a modulator.

1 is a diagram showing a configuration of an RF modulator.

In FIG. 1, reference numeral 102 denotes a clamp circuit, 104 denotes a switch circuit, 106 denotes a video mode terminal, 108 denotes a test pattern signal generation mode terminal, 110 denotes an image amplification circuit, Reference numeral 114 denotes a reference signal generator, reference numeral 116 denotes a carrier wave generating circuit, reference numeral 118 denotes a voice amplifying circuit, reference numeral 120 denotes a voice modulating circuit, reference numeral 122 denotes a frequency converting circuit, reference numeral 124 denotes a broadcasting system control circuit, reference numeral 126 denotes a voice Reference numeral 128 denotes an image signal source, reference numeral 130 denotes an audio signal source, reference numeral 132 denotes a broadcasting system control input terminal, reference numeral 134 denotes an input terminal of the reference signal generator 114, 136 denotes an RF output terminal, and 138 denotes an RF modulator.

The RF modulator is composed of a video part, an audio part, a logic part and an RF part.

The image portion is composed of a clamp circuit 102, a switch circuit 104 and an image amplification circuit 110. The clamp circuit 102 is a circuit for making one DC level of the AC voltage waveform such as a pulse waveform equal. The switch circuit 104 functions to determine whether the mode is a video mode or a test pattern signal generation mode and controls a voice signal inputted to the voice amplifying circuit 118 to prevent the direct current from reaching the voice amplifying circuit 118 . The image amplifying circuit 110 is used for amplifying a video signal and has a broadband frequency characteristic of 0 to several megahertz.

The voice section is constituted by a voice amplification circuit 118, an voice modulation circuit 120 and a voice oscillation circuit 126. The voice amplifying circuit 118 amplifies the voice signal output from the voice signal source 130. The voice modulation circuit 120 receives the signal output from the voice amplification circuit 118 and performs frequency modulation on the signal. The voice oscillation circuit 126 is a circuit for inputting a signal output from the broadcast system control circuit 124 to generate a voice subcarrier frequency and output it to the voice modulation circuit 120.

The logic unit includes a reference signal generator 114 and a broadcast control circuit 124. The reference signal generator 114 includes a programmable divider and a test pattern signal generator. The reference signal generator 114 receives a signal output from the voice modulation circuit 120 to generate a test pattern signal. The broadcast system control circuit 124 receives a signal output from the broadcast system control input terminal 132 and generates a signal for controlling the programmable frequency divider of the reference signal generator 114 to adjust the frequency division ratio.

The voice broadcasting system can be roughly divided into B / G, I and D / K systems.

The B / G broadcasting system is a system established by the Committee for International Communication (Committee for International Radiocommunication) and is mainly used in Western Europe. The B / G broadcasting system uses 5.5 megahertz (MHz) of the voice subcarrier frequency.

I broadcasting system is also being used by Irish, UK and other countries in a way created by the International Radio Communication Commission. I broadcasting system uses a voice subcarrier frequency of 6.0 megahertz.

The D / K broadcasting system is established by the Organization Internationale de Ratiodiffudion et Television (OIRT), and is used by countries such as China and the United States of Independent States. The D / K broadcasting system uses a voice subcarrier frequency of 6.5 megahertz.

The RF section is composed of a video modulating circuit 112, a carrier wave generating circuit 116 and a frequency converting circuit 122. The video modulation circuit 112 is a circuit for amplitude-modulating a video signal. The carrier wave generating circuit 116 is a circuit for generating a carrier wave which is a high frequency current used for transmitting and transmitting a low frequency signal and generates a specific RF channel frequency. The frequency conversion circuit 122 is a circuit for converting a received radio wave into an intermediate frequency, and inputs a signal output from the voice modulation circuit 120 and performs amplitude modulation.

The RF output terminal 136 is connected to a transmission antenna for propagating the signal output from the frequency conversion circuit 122 to a reception antenna such as a VCR. The video signal source 128 and the audio signal source 130 are baseband signals (signals that are not modulated relative to the carrier band signals), which are reproduction outputs of the recording / reproducing apparatus.

The operation of the RF modulator shown in FIG. 1 will now be described.

The signal outputted from the video signal source 128 is supplied to the clamp circuit 102 when the switch circuit 104 is in the video mode. And is clamped in the switch circuit 104. The switch circuit 104 is connected to the image mode terminal 106 and is input to the image amplification circuit 110. [ The signal amplified by the image amplifying circuit 110 is input to the image modulating circuit 112 by adjusting the input level. On the other hand, the signal output from the carrier wave generating circuit 116, which generates a specific RF channel frequency, is also input to the image modulation circuit 108. The image modulation circuit 112 amplitude-modulates the signals output from the image amplification circuit 110 and the carrier wave generation circuit 116 and outputs the modulated signals to the RF output terminal 136.

Next, when the switch circuit 104 is in the test pattern signal generation mode, the reference signal generator 114 connected to the test pattern signal generation mode terminal 108 operates, and the generated signal is input to the image amplification circuit 110 The operation thereafter is the same as that in the above-described image mode. The DC signal output from the voice signal source 130 is output to the voice amplifying circuit 118 and the voice modulating circuit 120 because the signal output from the voice modulating circuit 120 is used as the reference signal of the reference signal generator 114. [ It is necessary to control the voice amplifying circuit 118 using the switch circuit 104 so as not to be input to the voice amplifying circuit 118. [ This is because the voice modulation circuit 120 must not be modulated so that a signal having a predetermined oscillation frequency can be input to the reference signal generator 114 to generate a test pattern signal.

The signal output from the voice signal source 130 is input to the voice amplification circuit 118 and the voice amplification circuit 118 adjusts the voltage gain and outputs the result to the voice modulation circuit 120. The voice modulation circuit 120 frequency-modulates the signal output from the voice amplification circuit 118 to the voice subcarrier frequency oscillated by the voice oscillation circuit 126. Meanwhile, a part of the signals output from the voice modulation circuit 120 is input to the reference signal generator 114 through the input terminal 134 of the reference signal generator. The frequency conversion circuit 122 receives the signal output from the voice modulation circuit 120, amplitude-modulates the carrier wave output from the carrier wave generation circuit 116, and outputs the modulated signal to the RF output terminal 136.

FIG. 2 is a diagram for explaining a conventional audio broadcasting system in the RF modulator shown in FIG. 1. Referring to FIG.

In FIG. 2, reference numeral 202 denotes a programmable frequency divider, reference numeral 204 denotes a test pattern signal generator, and reference numerals 132a and 132b denote first and second broadcasting system control input terminals, respectively. The programmable frequency divider 202 is a circuit that receives a signal output from the input terminal 134 of the reference signal generator and divides the frequency by the control of the broadcasting system control circuit 124. The test pattern signal generator 204 is a circuit for generating a test graphic form (a combination of graphics composed of any specific circle or line) used for adjustment of the television receiver, and inputs a signal output in the programmable frequency divider 202 And generates a test pattern signal.

[Table 1]

division 132a 132b B / G Ground (low, 0) Open (high, 1) I Open (high, 1) Ground (low, 0) D / K Open (low, 0) Open (low, 0)

Table 1 is an input / output state table of the conventional audio broadcasting system control circuit shown in FIG.

First, the broadcasting system control signal shown in Table 1 is input from the broadcasting system control input terminals 132a and 132b to the broadcasting system control circuit 124. [ The broadcasting system control circuit 124 controls the programmable frequency divider 202 according to the state of the broadcasting system control signal to adjust the frequency division ratio. That is, the voltage of the broadcast system control input terminals 132a and 132b is compared with the reference voltage of the reference signal generator 114, and decoding is performed again on a 4-bit basis. The signal adjusted and output in the programmable frequency divider 202 is input to the test pattern signal generator 204 to be made into a certain type of image test pattern and output to the output terminal 108 of the reference signal generator 114, (110).

In this conventional technique, two control pins 132a and 132b and two selection switches (external components) are required to select one of three broadcasting schemes. This means an increase in the number of pins in the package type, which leads to an increase in the package assembly cost and requires two selection switches. Therefore, the printed circuit board size of the module of the RF modulator And an increase in cost. In addition, it is inconvenient for the user to control the two switches in order to change the audio broadcasting mode.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide a method and apparatus for controlling B / G, I, D / K broadcast And an audio broadcasting system control apparatus corresponding to the system.

1 is a diagram showing a configuration of an RF modulator.

FIG. 2 is a diagram for explaining a conventional audio broadcasting system in the RF modulator shown in FIG. 1. Referring to FIG.

FIG. 3 is a view for explaining a voice broadcasting system according to the present invention in the RF modulator shown in FIG. 1. FIG.

4 is a diagram showing a detailed configuration of the triple duty circuit shown in FIG.

According to another aspect of the present invention, there is provided an apparatus for controlling an audio broadcasting system of an RF modulator for a multi-broadcasting system, comprising: a video signal output unit for clamping an image signal output from an image signal source; ; A voice unit for amplifying a voice signal output from a voice signal source and frequency-modulating the voice signal at a voice subcarrier frequency; A signal output from one broadcasting control input terminal is input to a triple duty circuit to output a broadcasting system control signal for controlling three types of audio broadcasting systems and a test pattern signal generator signal is generated according to the broadcasting system control signal A logic unit for outputting to the amplifying circuit of the voice unit; And an RF unit for amplitude-modulating the video signal output from the video unit and the audio signal output from the audio unit at a specific RF frequency and outputting the resultant signal to an RF output terminal.

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

FIG. 3 is a view for explaining a voice broadcasting system according to the present invention in the RF modulator shown in FIG. 1. FIG.

3, reference numeral 302 denotes a triple duty circuit, and reference numerals 304 and 306 denote first and second output terminals (input terminals of the broadcasting system control circuit) of the triple duty circuit 302, respectively.

[Table 2]

division 132 304 306 B / G grounding low Hi I Vcc Hi low D / K Opening low low

Table 2 is an input / output state table of the triple duty circuit shown in FIG.

3, the triple duty circuit 302 is a circuit for controlling three broadcasting methods (B / G, I, D / K) with one control pin, and may be composed of three transistors and six resistors.

When the broadcasting system control signal is input from the broadcasting system control input terminal 132 to the triple duty circuit 302, the triple duty circuit 302 is connected to the triple duty circuit through the output terminals 304 and 306 as shown in Table 2, . The operation after input from the output terminals 304 and 306 of the triple duty circuit to the broadcasting system control circuit 320 is the same as that described in Fig.

4 is a diagram showing a detailed configuration of the triple duty circuit shown in FIG. In Fig. 4, Q1, Q2 and Q3 denote first to third transistors, respectively. The triple duty circuit includes a third transistor Q3 for inputting the voltage supplied to the broadcasting system control input terminal 132 to the base through the resistor R5 and outputting the collect voltage to the second output terminal 306 of the triple duty circuit, A second transistor Q2 that receives a voltage supplied from the broadcast control input terminal 132 through a resistor R5 and has a collector voltage as an output voltage and a second transistor Q2 that has a voltage output from the second transistor Q2 And a first transistor Q1 for inputting a reference voltage to a base through a resistor R3 and outputting a collect voltage to a first output terminal 304 of the triple duty circuit.

Next, the operation of the triple duty circuit 302 will be described with reference to FIGS. 4 and 2. FIG.

First, in the case of the B / K broadcasting system, when a DC voltage of 0 volt (ground) is inputted to the broadcasting system control input terminal 132, the voltage between the base and the emitter of the third transistor Q3 becomes 0 volt The voltage of the second output terminal 306 of the triple duty circuit is almost equal to Vcc since the third transistor Q3 is cut off and no voltage drop occurs through the resistor R6. However, in the case of the second transistor Q2, since the voltage between the base and the emitter becomes Vcc, the second transistor Q2 operates in the active region. Accordingly, a voltage drop occurs through the resistors R3 and R2, and the first transistor Q1 is turned on through the resistor R2. Then, when a voltage drop occurs due to the resistor R1 and a voltage drop through the resistor R1 is sufficiently large, the first transistor Q1 is operated in a saturated state. The voltage of the first output terminal 304 of the triple duty circuit becomes nearly zero volts and is recognized as a low state. Next, when the broadcasting system is I, the voltage of the broadcasting system control input terminal 132 is Vcc in Table 2, so that the second transistor Q2 is operated and the third transistor Q3 is in the off state in FIG. Therefore, the voltage of the first output terminal 304 of the triple duty circuit becomes high (Vcc), and the voltage of the second output terminal 306 of the triple duty circuit becomes low (ground). Finally, when the broadcasting system is D / K, the voltage of the broadcasting system control input terminal 132 is in the open state in Table 2. Thus, the bases of the second and third transistors Q2 and Q3 are connected to each other in FIG. , The voltage between the base and the emitter of the second transistor Q2 is almost Vcc, so that the second transistor Q2 operates and the third transistor Q3 operates again. Therefore, the first and second output terminals 304 and 306 of the triple duty circuit are simultaneously subjected to the low voltage. The audio broadcasting systems controlled by the two broadcasting system control input terminals 132a and 132b shown in FIG. 2 and Table 1 are implemented by the same broadcasting system control input terminal 132 shown in FIG. 3 and Table 2 Able to know.

The above result can be used without modification of the broadcasting system control circuit used in the prior art. That is, if only a triple duty circuit is added between the broadcasting system control input terminal and the broadcasting system control circuit, the object of the present invention can be achieved. In addition, although the triple duty circuit is implemented with three transistors and six resistors in FIG. 4, another structure can be implemented.

As described above, according to the present invention, it is possible to control the audio broadcasting system with one control pin and one control switch, thereby reducing the number of package pins and reducing external components,

.

Claims (3)

An image unit for clamping a video signal output from a video signal source and switching and amplifying the video signal between a video mode and a test pattern signal generation mode; A voice unit for amplifying a voice signal output from a voice signal source and frequency-modulating the voice signal at a voice subcarrier frequency; A control unit for outputting a broadcasting system control signal for controlling three audio broadcasting systems by inputting a signal outputted from one broadcasting system control input terminal, generating a test pattern signal by the broadcasting system control signal and outputting the test pattern signal to the audio unit, part; And And an RF unit for amplitude modulating the video signal output from the video unit and the audio signal output from the audio unit at a specific RF frequency and outputting the amplified audio signal to an RF output terminal. 2. The apparatus of claim 1, wherein the logic unit A triple duty circuit for inputting a signal output from one broadcasting mode control input terminal and outputting a broadcasting mode control signal for controlling three types of audio broadcasting modes; A broadcasting scheme control circuit for receiving the broadcasting scheme control signal and controlling a broadcasting scheme; And And a reference signal generator for generating a test pattern signal under the control of the broadcast mode control circuit. 3. The circuit of claim 2, wherein the triple duty circuit A third transistor for inputting a voltage supplied to the broadcast control input terminal to a base through a resistor R5 and outputting a collect voltage to a second output terminal of the triple duty circuit; A second transistor for inputting a voltage supplied from the broadcasting system control input terminal to the base through the resistor R5 to make a collective voltage as an output voltage; And And a first transistor for inputting a voltage output from the second transistor to a base through a resistor R3 and outputting a collect voltage to a first output terminal of the triple duty circuit, Device.