KR910004404Y1 - Output control circuit on audio system - Google Patents

Abstract

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Description

Output Control Circuit of TV Band Built-in Tuner

1 is a circuit diagram of the present invention.

* Explanation of symbols for main parts of the drawings

10: function selection unit 20: aerial

30: first broadcast selector 40: first intermediate frequency amplification and third broadcast selector

50: sound separation unit 60, 61: first, second filter

70: second broadcast selector 80: second intermediate frequency amplifier and sound separation unit

Q1-Q6: 1-6 transistor R1-R10: resistor

SW1-SW3: 1-3 switch D1-D7: Diode

The present invention relates to a tuner (Tunner) with a built-in television broadcast band in an audio system, and more particularly to a circuit for controlling the output of the tuner according to the band selection.

The tuner of the conventional audio system has been designed to receive an Amplitude Modulation (AM) broadcast band and a Frequency Modulation (Frequency Modulation) FM band. With the introduction of new technology, TV bands have been added to receive television bands.

The tuner with the built-in TV band is composed of the FM band, the TV low band and the TV high band as a common band to select the broadcast frequency band and pushes the function selection switch to select the band. It consists of a switch (Pushswitch).

However, such a tuner has a problem in that a component circuit is complicated by using a push switch as a function selection switch and pop noise occurs when switching a band, and FM broadcasting band, TV low broadcasting band and TV high broadcasting band are used as common bands. As a result, there was a problem in that frequency interference was caused by a slight intermediate frequency difference of 225 MHZ between a TV high broadcasting band of 10.925 MHZ, an FM broadcasting band of 10.7 MHZ, and a TV low broadcasting band.

Therefore, the purpose of the present invention is to separate TV high broadcasting band and FM broadcasting band and TV low broadcasting band, and use the function selection integrated circuit to prevent pop noise caused by band switch and interference between FM / TV low broadcasting band and TV high broadcasting. It is to provide an output control circuit of a TV built-in tuner that can be prevented.

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

1 is a circuit diagram of the present invention, a first switch SW1 for selecting AM broadcast bands, a second switch SW2 for selecting FM and TV low broadcast bands, and a third switch for selecting TV high broadcast bands. Selecting the first to third switches SW1 to SW3 by inputting the switch SW3 and the states of the first to third switches SW1 to SW3 to the first to third input terminals I1 to I3, respectively. A first power source connected to the emitter by the function selection unit 10 for generating a signal at the first to third output terminals O1 to O3 and the first selection signal input to the base through the resistor R1; A first power source connected to the emitter by a first transistor Q1 for generating a first control signal by outputting or shorting VCC) through a collector and the second selection signal input to the base through a resistor R2; The second transistor Q2 which generates a second control signal by outputting or shorting (VCC) through the collector and the input which is input to the base through the resistor R3. A third transistor Q3 for generating a third control signal by outputting or shorting the first power supply VCC connected to the emitter by a three-selection signal; and the second applied through the diode D2. Any broadcast in the FM broadcast band or TV low band selected by the viewer's selection among the broadcast signals received on the aerial line 20 by being turned on and off according to the second control signal of the transmitter Q2. Any broadcast in the AM broadcast band selected by the viewer according to the first control signal of the first broadcast selector 30 for selecting only a signal and the first control signal of the first transistor Q1 applied through the diode D1. The first intermediate frequency amplifier and the first amplifier for selecting a signal and outputting it through a first output terminal or amplifying an FM broadcast signal or a TV low broadcast signal of the first broadcast selector 30 through a second output terminal. 3 through the broadcast selector 40 and diodes (D3, D4) to the base Is controlled by a third control signal to be applied or a second control signal applied to the base through the diodes D2 and D6 and is output from the first output terminal of the first intermediate frequency amplifier and the third broadcast selector 40. From the fourth transistor Q4 which mutes the selected AM broadcast signal to the second power source GND through the collector and the emitter, and from the second output terminal of the first intermediate frequency amplifier and the third broadcast selector 40. The first and second output terminals are divided into the FM or TV low broadcast signal input to the left (hereafter referred to as L) audio signal and the right (hereafter referred to as R) audio signal. A voice filter 50 for outputting through the voice filter, a first filter 60 that blocks noise of high-frequency components of the L-channel voice signal of the voice splitter 50, and passes only the voice signal of the L-channel, and the voice splitter Only the R channel audio signal is removed by removing noise of a high frequency component from the R channel audio signal of 50. The overload is applied to the base via the second filter 61 and the second control signal or diodes D1 and D7 and resistor R7 applied to the base via diodes D2 and D6 and resistor R7. A switching operation is performed by the first control signal and the selected AM broadcast signal of the first intermediate frequency and third broadcast selection unit 40 or the first filter 60 inputted to the collector through the resistor R5 to the collector. The fifth transistor Q5 for outputting the input L channel audio signal to the L channel output terminal through the emitter, and the second control signal or diode applied to the base through the diodes D2 and D6 and the resistor R8 ( The first intermediate frequency amplification and the third broadcast selector 40, which are switched to each other by the first control signal applied to the base through the resistors R8 and D1 and D7, and are input to the collector through the resistor R6. Emitter is selected from the selected AM broadcast signal or R channel audio signal inputted from the second filter 61 to the collector. The third control signal of the sixth transistor Q6 output to the R-channel terminal and the third transistor Q3 applied through the diode D3 is turned on and off, and the viewer can select one of the TV high bands. A second selector 70 for selecting a broadcast signal, an intermediate frequency amplified random broadcast signal of the selected TV high band input from the second broadcast selector 70, and an L-channel audio signal and an R-channel audio signal. The L channel audio signal is output to the L channel output terminal through the first output terminal and the resistor R9 and the R channel audio signal is output to the R channel output terminal through the second output terminal and the resistor R10. It consists of two intermediate frequency amplification and sound separation unit (80).

Based on the above configuration will be described the present invention in detail.

First, when the AM broadcast band is selected first, when the listener presses only the first switch SW1 to select the AM broadcast band, the first switch SW1 is turned on, so that the first input terminal of the function selector 10 is selected. (11) is short-circuited with the 2nd power supply GND.

The function selector 10 for inputting the second power source GND to the first input terminal 11 by the first switch SW1 generates the second and third selection signals in the high logic state to generate the resistors R2 and R3. ) Is applied to the bases of the second and third transistors Q2 and Q3 to turn them off, thereby causing the second and third transistors to generate low logic second and third control signals, and to generate a low logic first selection signal. It is applied to the base of the first transistor Q1 through the generating resistor R1 to turn on the first transistor Q1 to output the first power supply VCC that is applied to the emitter through the collector. By generating a first logic control signal of high logic.

At this time, the first intermediate frequency amplification and the third broadcast selector 40 select any broadcast signal among AM broadcast bands selected by the listener by the high logic first control signal applied from the collector of the first transistor Q1. It selects and outputs to the line 1 via a 1st output terminal.

Then, the fifth transistor Q5 for inputting any broadcast signal of the selected AM broadcast band on the line 1 to the collector through the resistor R5 is applied through the diodes D1 and D7 and the resistor R7. It is turned on by the high logic first control signal and outputs the input signal to the L-channel output terminal Lout, and the sixth transistor Q6 is also applied through the diodes D1 and D7 and the resistor R8. Any broadcast signal of the selected AM broadcast band on the line 1, which is turned on by the first control signal and input to the collector through the resistor R6, is output through the emitter to the R channel output terminal Rout.

At this time, the first and second broadcast selection units 30 and 70 and the fourth transistor Q4 are in an off state by the second and third control signals of low logic.

Secondly, if the listener wants to listen to the FM and TV low band, when the listener presses the second switch SW2 to select the FM and TV low band, the second switch SW2 is turned on so that the second switch of the function selection unit 10 is turned on. While the input terminal I2 and the second power source GND are connected to each other, the first or third switch SW1 or SW3 which is turned on in association with the second switch SW2 is turned off.

The function selection unit 10 for inputting the second power source to the second input terminal I2 by the second switch SW2 may output the first and third selection signals of the high logic to the first and third output terminals O1,. The first and third transistors Q1 and Q3 are turned off by applying the generated first and third transistors Q1 and Q3 to the base of the first and third transistors Q1 and Q3 to cause the first and third transistors Q1 and Q3. The third control signal is generated respectively, while the low logic second selection signal is applied to the base of the second transistor Q2 through the second output terminal O2 and the resistor R2 to generate the second transistor Q2. By turning on, the second transistor causes the first power supply VCC applied to the emitter to be output through the collector to generate a high logic second control signal.

At this time, the first broadcast selector 30 is turned on by the high logic second control signal applied from the second transistor Q2 through the diode D2, and the listener is selected from among the plurality of broadcast signals input through the aerial line 20. Any broadcast signal of the selected FM and TV low bands is selected and output to the first intermediate frequency amplifier and the third broadcast selector 40.

The first intermediate frequency amplifier and the third broadcast selector 40 for inputting the broadcast signals of the FM and TV low bands selected from the first broadcast selector 30 are first transistors Q1 through the diode D1. The output of the first broadcast selector 30 is amplified by an intermediate frequency by a low logic first control signal, and is output to the acoustic separation unit 50 through the second output terminal.

Then, the acoustic separation unit 50 separates the L channel audio signal and the R channel audio signal from the output of the first intermediate frequency amplifier and the third broadcast selector 40 through the first output terminal and the second output terminal, respectively. Output to the first and second filter (60, 61).

The first filter 60 which inputs the L-channel audio signal from the first output terminal of the acoustic separation unit 50 may include only the L-channel audio signal from which the noise of the high frequency component included in the signal is removed from the fifth transistor Q5. The second filter 61, which outputs to the collector and inputs the R channel voice signal from the second output terminal of the acoustic separation unit 50, also removes only the R channel voice signal from which noise of high frequency components included in the signal is removed. Outputs to the collector of 6 transistor (Q6).

Then, the fifth transistor Q5 is turned on by the high logic second control signal applied to the base from the second transistor Q2 through the diodes D2 and D6 and the resistor R7 and is input to the collector. The output of the filter 60 is output through the L-channel output terminal Lout through the emitter, and the sixth transistor Q6 also connects the diodes D2 and D6 and the resistor R8 from the second transistor Q2. The output of the second filter 61, which is turned on by the high logic second control signal applied to the base and is input to the collector, is output through the emitter to the R channel output terminal Rout.

At this time, the fourth transistor Q4 is turned on by the high logic second control signal applied to the base through D2 and D5, and is connected to the line by the first intermediate frequency amplifier and the third broadcast selector 40. AM broadcast signal or noise signal which can be output to 1) is inputted to the collector and muted by grounding to the second power supply (GND) through the emitter.

In addition, the second broadcast selector 70 is in an OFF state by the low logic third control signal of the third transistor Q3 applied through the diode D3 and does not operate.

Lastly, if the listener wants to listen to the TV high broadcast band, when the listener presses the third switch SW3 to select the TV high broadcast band, the third switch SW3 is turned on to turn on the third of the function selector 10. The first terminal and the second switch SW1 or SW2 which are connected to the third switch SW3 are turned off while the input terminal I3 and the second power source GND are connected to each other.

The function selector 10 for inputting the second power source GND to the third input terminal I3 by the third switch SW3 receives the first and second selection signals of high logic in the first and second output terminals. Low logic logic by turning off the first and second transistors Q1 and Q2 by applying them to the bases of the first and second transistors Q1 and Q2 through the respective resistors R1 and R2 respectively generated in (O1 and O2). While the first and second control signals are generated, the third transistor Q3 is applied to the third output terminal O3 by applying a low logic third selection signal to the base of the third transistor Q3 through the generation resistor R3. ) To cause the third transistor to output the first power supply VCC input to the emitter through the collector to generate a high logic third control signal.

At this time, the second broadcast selector 70 is turned on by the third control signal of the logic applied from the third transistor Q3 through the diode D3 and is a listener among a plurality of broadcast signals input through the aerial line 20. Selects an arbitrary broadcast signal of the TV high band selected by the second high frequency amplifier and outputs it to the second intermediate frequency amplification and sound separation unit 80;

Then, the second intermediate frequency amplifier and sound separation unit 80 converts the broadcast signal of the selected TV high broadcast band input from the second broadcast selector 70 into the L channel audio signal and the R channel audio signal while simultaneously The separated L channel audio signal is output to the L channel output terminal Lout through the first output terminal and the resistor R9, and the separated R channel voice signal is output to the R channel through the second output terminal and resistor R10. Output to the output terminal (Rout).

At this time, the fourth transistor Q4 is turned on by the third control signal of the high logic state applied from the third transistor Q3 to the base through the diodes D3 and D4 and can be generated on the line 1. The broadcast signal and noise component of the band are input to the collector and are fed to the second power supply GND through the emitter, while the fifth and sixth transistors Q5 and Q6 are controlled by the low logic first and second control signals. It is turned off to block the noise component that can be input to the collector, the broadcast signal of AM broadcast band, or the broadcast signal of FM and TV low band, and the first broadcast selector 30 is also turned off by the low logic second control signal. It does not work.

The function selection unit 10 of the above configuration is a possible selection circuit identified in the object field, and it will be understood that the same meanings do not have to be mentioned separately. The first control signal is an AM broadcast band, an FM and TV low broadcast band, and a TV high broadcast band. It is a control signal for outputting a broadcast signal, and the 1-3 selection signal specifies that it is a selection signal for selecting any one of the broadcast bands.

As described above, the present invention provides the advantage of simplifying the circuit and preventing pop noise by the push switch using a function selection circuit, and separately controlling the FM and TV low broadcasting band and the TV high broadcasting band selecting unit. There is an advantage to prevent the frequency interference and to prevent the output of unnecessary noise signal part.

Claims (2)

In an audio system, a first switch SW1 for selecting an AM broadcast band, a second switch SW2 for selecting FM and TV low broadcast bands, and a third switch for selecting a TV high broadcast band ( SW3) and the states of the first to third switches SW1 to SW3 are respectively input to the first to third input terminals I1 to I3 to receive the first to third selection signals for the switches SW1 to SW3. Selecting and outputting the audio signal in the broadcast frequency band of the broadcast band selected by the function selection unit 10 generated in the 1-3 output terminals O1-O3 and the 1-3 selection signal of the function selection unit 10. The system control means for generating the 1-3 control signal to control the system, and among the broadcast signal received on the aerial line 20 is turned on (OFF) according to the second control signal of the system control means A first broadcast selecting section 30 for selecting only a broadcast signal in an FM broadcast band or a TV low band selected by a viewer's selection, and the system According to the first control signal of the fishing means, any broadcast signal in the AM broadcast band selected by the viewer's selection is selected and output through the first output terminal, or the FM broadcast signal of the first broadcast selector 30 or TV. A first intermediate frequency amplifier and a third broadcast selector 40 for amplifying a low broadcast signal through an intermediate frequency amplifier and outputting the same through a second output terminal, and controlled by a third control signal or a second control signal of the system control means. Muting means for muting the selected AM broadcast signal outputted from the first intermediate frequency amplifier and the first output terminal of the third broadcast selector 40, and the first intermediate frequency amplifier and the third broadcast selector 40. The intermediate frequency-amplified FM or TV low broadcast signal input from the second output terminal is divided into the audio signal of the left (hereinafter referred to as L) channel and the audio signal of the right (hereinafter referred to as R) channel. Voice separation unit 50 for outputting through the 1, 2 output terminal, and A first filter 60 which blocks noise of the high frequency component of the L channel voice signal of the voice separator 50 and passes only the voice signal of the L channel, and noise of the high frequency component of the R channel voice signal of the voice separator 50. A second filter 61 which passes only the audio signal of the R channel, and switches by the second control signal or the first control signal of the system control means, so that the first intermediate frequency and the third broadcast selector Output control means for controlling the output of the selected AM broadcast signal (40) or the L-channel voice signal of the first filter (60) and the R-channel voice signal of the second filter (61), and the third of the system control means; A second selector 70 for turning on or off a control signal and selecting a broadcast signal among TV high bands by a viewer's selection, and a selected TV high band input from the second broadcast selector 70. Intermediate frequency amplification of any broadcast signal, L channel audio signal and R channel And a second intermediate frequency amplification and sound separation unit (80) for separating audio signals and outputting them to the L channel and the R channel output terminals, respectively. The method according to claim 1, wherein the system control means generates a first control signal by switching by the first selection signal of the function selection unit 10 to generate the first control signal and the third intermediate amplifier and the third broadcast selection unit 40. The first switching means for outputting in one direction to the output control means, and the switching operation by the second selection signal of the function selection unit 10 generates a second control signal to mute means, the output control means and the first broadcast selection unit ( The second switching means for one-way output to 30) and the switching operation by the third selection signal of the function selection unit 10 to generate a third control signal and to output the one-way direction to the mute means and the second broadcast selection unit 70. An output control circuit of a television band built-in tuner, characterized in that it comprises a third switching means.