KR900009747Y1 - Speakable circuit of image recording & reproducing apparatus - Google Patents

Abstract

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Description

Speak Able Circuit of Video Record Player

1 is a loudspeaker circuit according to the present invention.

* Explanation of symbols for main parts of the drawings

10: microphone input control unit 20: recording audio signal switching unit

25: output audio switching unit 30: audio playback unit

40: audio output control unit ARP: audio recording unit

MCAMP: Microphone Amplifier PB: Playback Amplifier

HP: Headphone Amplifier

The present invention relates to an audio input circuit of a video tape recorder, and in particular, an audio input circuit which allows an audio signal output from the video recorder to be communicated while listening to a headphone. Speakable of the loudspeaker circuit.

A typical video recording player has a signal input / output circuit for audio / video dubbing, and records audio / video signals input through an external connection line or outputs audio / video signals that are played back. I stopped.

Also, while listening to the audio signal reproduced and output from the video recorder with the headphone, it is impossible to talk with others.

Therefore, in the conventional video recording player, it is inconvenient to remove the headphones when starting a conversation with a third party while listening to the playback audio signal using the headphones.

Accordingly, an object of the present invention is to provide a loudspeaker circuit that enables a conversation while listening to an audio signal reproduced and output from a video recorder.

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

FIG. 1 is a loudspeaker circuit diagram according to the present invention, and a selection switch for selecting a signal of an audio dubbing signal input line jack 1 and an inputter jack 2 for inputting an audio signal reproduced and output from a system internal tuner unit. A loudspeaker switch (SPS) and a resistor (R1) are connected in series between the (ISS), the power supply voltage (Vcc), and a plate, and the resistor (R2) and the microphone jack (3) are connected to each other. The microphone input control unit 10 for amplifying the microphone enable signal and the microphone signal by the microphone enable signal and the microphone plug according to the switching of the microphone amplifier (MCAMP), the microphone of the speaker switch (SPS) and the microphone jack (3) The handgate G1 which gates the microphone mode control signal by the insertion signal and the collector are connected in common and input the output of the selection switch ISS and the output of the microphone amplifier MCAMP to each emitter. remind A recording audio switching unit 20 consisting of transistors Q1 and Q2 for outputting the output signal to the collector by switching the output signal by the microphone insertion signal and the output of the AND gate G1, and the collector and the emitter are connected to the output terminal. The emitter and the collector are connected to the output of the selection switch ISS and the microphone amplifier MCAMP, and a base is connected to the speaker enable signal of the microphone input controller 10 so that the loudspeaker switch SPS is connected. ), An input audio switching unit 25 for selectively switching the output of the selection switch ISS or the microphone amplifier according to the switching of the switch, and a switch S1 for selecting the recording and playback back modes. An audio recording process (ARP) for amplifying, equalizing, and outputting the audio signal input by the selection of the mode selection switch S1, and the audio picked up and amplified by the playback head; An audio playback unit 30 comprising an audio play process (APP) for equalizing and outputting a signal, an amplifier (OP) and a capacitor (C7) for amplifying the playback audio, and an output from the transistors Q3-Q4. A line amplifier LP for amplifying an audio signal, a switch S2 for switching recording and playback modes, an audio dubbing signal and a microphone signal input to each collector by the operation logic of the loudspeaker switch SPS; It is composed of a headphone head HP which outputs to the headphone jack 7 by amplifying the output of the transistors Q5-Q6 that perform the audio mute operation while simultaneously outputting the reproducing audio signal.

In FIG. 1, reference numerals C 1 to C 7 denote coupling capacitors.

The microphone input jack 3 connects a resistor R2 to a conventional microphone input jack, and the connection point P1 of the resistor R2 is connected to ground unless a microphone plug is inserted into the microphone jack 3. When the microphone plug is inserted, it is separated from the ground to reach the supply voltage level.

The tuner of the system in the Direct Mode (EE) state, where the switch contacts of the input selector switch (ISS) and the mode selector switch (S1-S2) are now switched to (A), (A ') and (a). When a signal that is tuned negatively and converted into a voice signal is input, it is input to the emitters of the transistors Q1 and Q3 through the coupling capacitor C1.

At this time, when the microphone plug is inserted into the microphone jack 3, the "high" signal by the resistor R2 is input to the terminal (a1) of the AND gate G1 and the base of the transistor Q1, so that the transistor Q1 is turned off. The transistor Q3 is " turned on " by the " low " signal input to the base, and outputs the television voice signal thrusted by the tuner section to the coupling capacitor C4 connected to the collector end, thereby to " turn on " Only the signal by is amplified by the line amplifier LP.

The audio signal of the amplified tuner unit is outputted to the audio line output jack 5 and the tuner signal output jack 6 through the switch S2 and the capacitor C5 switched to the capacitor C3 and the contact point a. , Amplified by the headphone amplifier (HP) and output to the headphone jack (7).

As described above, when a voice signal is supplied to the headphone jack 7, the user hears the broadcast sound of the television through the headphone.

When the user presses the speaker switch SPS while listening to the broadcast sound in the EE mode, the voltage of the "high" state caused by the load resistor R1 is changed to the base of the transistors Q3-Q6 and the gate of the AND gate G1 (b1). ) Is input to the terminal.

At this time, since the "high" signal by the resistor R2 is input to the terminal a1 of the AND gate G1 when the microphone plug is inserted, the AND gate G1 transmits the "high" signal to the base of the transistor Q2. Enter

As a result, transistor Q2 is " off " transistor Q3 is " off ", and transistors Q4-Q6, which input the " high " signal by pressing the speaker switch SPS, are " on " .

Therefore, in EE mode, the tuner output audio signal input to the tuner signal input terminal 2 and output from the selector switch ISS is cut off by the " off " of the transistors Q1, Q2, Q3, and the microphone jack 3 Only the voice signal of the microphone, amplified by the microphone amplifier MCAMP, is input to the line amplifier LP through the collector and the emitter of the transistor Q4.

Therefore, the microphone voice signal output from the microphone jack 3 is input to the headphone amplifier HP through the switching S2 which is second amplified by the line amplifier LP and then switched to the contact point a. Therefore, it can be seen that the person who listened to the voice signal of the E-E state by the headphone listens to the voice of the other party.

On the other hand, when the mode selection switches S1 and S2 are switched to the contacts B 'and (b) and the state of the system is in the playback mode, the playback signal picked up from the video data by the playhead is audio. It is input to the regeneration circuit APR.

The audio reproduction circuit APR compensates for gain by equalizing the audio signal picked up from the video tape and outputs it to the collector of the transistor Q6 after amplification through the reproduction amplifier PB. The reproduced audio signal input to the collector of the transistor Q6 is inputted to the headphone amplifier HP by the switch S2 switched to the capacitor C6 and the contact point b so that the user of the user connected to the headphone jack 7 can be connected. Input to the headphones.

When the loudspeaker switch SPS is pressed while listening to the audio signal picked up from the video tape through the headphones as described above, the "high" level loudspeaker signal by the resistor R1 is the same as that of the AND gate G1. It is input to the input terminal b1 and the base of the transistors Q3, Q4, Q5 and Q6.

Thus, transistor Q3 is " off " and transistors Q4, Q5 and Q6 are " on ", so that the external audio signal input from the microphone inserted into microphone jack 3 is not supplied with the microphone amplifier (as described above). After primary amplification in MCAMP, it is output through the collector-emitter of transistor Q4. The microphone audio signal output from the emitter of the transistor Q4 is second amplified to a predetermined level by the line amplifier LP and input to the collector of the transistor Q5 that is switched on.

At this time, the reproduced audio signal amplified by the reproduced amplifier PB is bypassed to ground through the collector-emitter of the on-switched transistor Q6, so that the reproduced audio signal is muted.

On the other hand, since the transistor Q5 which inputs the external audio signal (microphone signal) amplified and output from the line amplifier LP to the collector is in the "on" state, the signal output from the microphone jack 3 is input to the headphone amplifier HP. It can be seen that. Therefore, when the speaker switch SPC is pressed in the regeneration mode in which the mode selection switches S1 and S2 are switched to the contacts B 'and (b), they are picked up from the regeneration head and amplified by the regeneration amplifier PB. The reproduced audio signal is muted by the transistor Q6, and the external audio signal (microphone signal) amplified by the microphone amplifier MCAMP is the transistor Q4, the line amplifier LP, the transistor Q5 and the headphone amplifier ( Through HP) to the listener's headphones.

If there is an input of the microphone jack 3 in the recording mode in which the mode selection switches S1-S2 are switched to the contacts A 'and (a), the transistor Q1 is "off" and the transistor Q2 is "turned on". The output signal of the microphone amplifier MCAMP is input to the audio recording unit ARP through the emitter and the collector of the transistor Q2 and recorded as a take, and when the microphone plug is removed from the microphone jack 3, the transistor Q1 Is " turned on " and a signal input to the audio input line jack 1 or a broadcast signal in EE mode is input to the audio recording unit ARP, whereby it is recorded on the audio track of the video tape.

As described above, the present invention is a simple circuit, which allows the user to talk with others while listening to audio signals while wearing headphones in direct mode or playback.

Claims (2)

A selection switch ISS for selecting one of the audio signals output from the audio input line and the system tuner unit, a switch S1 for switching the input audio signal, and an audio signal selected and connected to the switch S1. An audio recording unit (ARP) for compensating and outputting the recording signal to the videotape, a headphone amplifier (HP) for amplifying the audio signal and outputting it to the headphones, and an audio reproducing unit for equalizing and amplifying the signal picked up from the videotape. A speaker enable circuit of a video recording / reproducing apparatus (30), comprising a speaker enable switch (SPS), a speaker enable logic by a switching operation of the speaker enable switch (SPS), and a microphone insertion signal by microphone insertion; The microphone input control circuit 10 for amplifying and outputting an external audio signal through the microphone and the collector are commonly connected. The output of the selector switch ISS and the output of the microphone amplifier MCAMP are input to the emitter of the transistor Q1 which switches the input signal by the microphone insertion signal and the output of the AND gate G1 to output to the collector. A recording audio switching unit 20 composed of Q2), a collector and an emitter are connected to an output terminal, and each emitter and collector are connected to an output of the selection switch ISS and a microphone amplifier MCAMP, An input audio switching unit 25 having a base connected to the speaker enable signal of the microphone input control unit 10 and selectively switching an output of a selection switch ISS or a microphone amplifier according to a switch of the speaker switch SPS; Input to the switching output voice signal of the input audio switching unit 25 and the audio signal reproduced and output from the audio reproducing unit 30 to select one of the two inputs according to the operation mode to And an audio signal output control unit 40 which outputs to the phone amplifier HP and performs a switching operation when a loudspeak signal is input to output only the output of the input audio switching unit 25 to the headphone amplifier HP. A loudspeaker circuit of a video recorder. The audio output control unit 40 of claim 1, wherein the audio output control unit 40 mutes the line amplifier LP for amplifying the signal of the input audio switching unit 25 and the output of the audio reproduction unit 30 by a predetermined signal. A transistor Q5 connected to a collector of transistor Q6 and connected to a collector and an emitter at both ends of a mode selector switch S2 for switching the output of the line amplifier LP and the collector output of the transistor Q6; And a circuit for inputting the speaker enable signal output from the microphone input controller 10 to the transistors Q5 and Q6 to mute the playback audio signal and to switch and output the microphone input audio. Speak Enable circuitry of the recorder.