JPH02123503A - Sound signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To lower high area frequency noise with an inexpensive and simple circuit by using a mike amplifier which is built in a sound recording reproduction IC and unused. CONSTITUTION:At the time of inputting to the mike, a change-over switch 3 switches the connection from an ordinary input terminal 1 to the mike input terminal 2 and a mike amplifier 10 is operated by the action of a transistor (Tr) part 11. A sound signal inputted from the terminal 2 to the mike amplifier 10 of a high area frequency reduction amplifier 4 is outputted from the amplifier 10 and the noise of the high area frequency inputted accompanying the sound signal is reduced by the action of a capacitor 12 of the Tr part 11. At the time of inputting ordinarily, the connection of the switch 3 is switched to the terminal 1 and the amplifier 10 is not operated by the action of the Tr part 11. The sound signal outputted from the amplifier 10 is recorded in a magnetic tape 9. Consequently, only at the time of inputting to the mike, the noise of the high area frequency is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an audio signal recording and reproducing device, and in particular to an audio signal recording and reproducing device that uses a built-in microphone amplifier in a recording and reproducing IC to reduce high frequencies at the time of microphone input. be.

Conventional technology In recent years, due to the spread of VTRs and video cameras.

More and more individuals are paying for movies (video software). Therefore, it has become necessary to first edit and splice the recorded footage together, and then perform post-recording editing to record the audio. This dubbing editing is performed by recording the audio signal input from either the audio input terminal or the microphone input terminal on tape, and the audio signal input from the microphone input terminal is amplified by a microphone amplifier.

It was input to the switch that switches between the microphone input terminal and the audio input terminal.

Problems to be Solved by the Invention However, with the above configuration, there is a problem in that when post-recording editing is performed on an audio signal input from a microphone input terminal, even high-frequency noise is recorded.

The present invention solves the above problems, and focuses on the fact that the microphone amplifier built in a recording/playback IC is not used in conventional circuits, and uses this microphone amplifier as a microphone amplifier with the above configuration. It is an object of the present invention to provide an audio recording and reproducing device that reduces high frequency noise using an inexpensive and simple circuit.

Means for Solving the Problems In order to solve the above problems, the present invention provides a microphone input terminal having a switch instruction circuit, and a switch section that switches between a normal input terminal and a microphone input terminal according to an instruction signal of the switch instruction circuit. , a microphone amplifier built into the recording/playback IC, which operates upon receiving an instruction signal from the switch instruction circuit, and reduces high-frequency noise input from the microphone input terminal via the switch section. It is something.

Effect: According to the above configuration, at the time of microphone input, the switch instruction circuit of the microphone input terminal gives an instruction signal to the switch unit and the microphone amplifier, the switch unit switches the connection from the normal input terminal to the microphone input terminal, and the microphone amplifier is activated. The audio signal that is input from the microphone input terminal to the microphone amplifier through the switch section is increased in signal level and output from the microphone amplifier, and the high-frequency noise that is input along with this audio signal is is lowered by the microphone amplifier. Further, during normal input, the connection of the switch section is switched to the normal input terminal by the instruction signal from the switch instruction circuit, and the microphone amplifier is no longer operated. For this reason, the audio signal input from the first input terminal to the microphone amplifier through the switch section is output without being amplified. Therefore, only at the time of microphone input, the microphone amplifier built in the recording/reproduction IC is operated to reduce high frequency noise.

Example An embodiment of the present invention will be described below with reference to the drawings.

1 and 2, a normal input terminal 1 and a microphone input terminal 2 are connected to a changeover switch 3, and the microphone input terminal 2 is provided with a switch instruction circuit. Also,
The changeover switch 3 switches the connection between the normal input terminal 1 and the microphone input terminal 2 in response to an instruction signal from a switch instruction circuit for the microphone input terminal 2. and,
The output end side of the changeover switch 3 is connected to a high-frequency frequency reducing microphone amplifier 4, and this high-frequency frequency reducing microphone amplifier 4 is built in a recording/playback IC and is activated in response to an instruction signal from a switch instruction circuit. is being done. Also,
A control line 5 of a switch instruction circuit of the microphone input terminal 2 is connected to the changeover switch 3 and the high frequency lowering microphone amplifier 4.

The high frequency lowering microphone amplifier 4 is connected to the audio head 8 via a recording/reproducing amplifier 6 and a recording amplifier 7. Further, 9 is a magnetic tape.

FIG. 2 shows the circuit configuration of the high frequency lowering microphone amplifier 4, which includes a microphone amplifier 10 and a transistor section 11 that controls the operation of the microphone amplifier 10, and an input terminal of the microphone amplifier 10. 12 is connected to the output end of the changeover switch 3, and a signal input terminal 13 of the transistor section 11 is connected to the control line 5. moreover,
The output terminal 14 is connected to the recording/reproducing amplifier 6.

The effects of the above configuration will be explained below.

First, at the time of microphone input, the switch instruction circuit of the microphone input terminal 2 gives an instruction signal to the changeover switch 3 and the transistor part 11, and the changeover switch 3 switches the connection from the normal input terminal 1 to the microphone input terminal 2, and also switches the connection to the microphone input terminal 2. The microphone amplifier 10 is operated by the action of the section 11. Then, the audio signal input from the microphone input terminal 2 to the microphone amplifier 10 through the changeover switch 3 has its signal level increased and is output from the microphone amplifier 10.
High-frequency noise input along with this audio signal is reduced by the action of the capacitor 12 of the transistor section 11. Further, during normal input, the connection of the changeover switch 3 is switched to the normal input terminal 1 by the instruction signal from the switch instruction circuit, and the microphone amplifier 10 is not operated due to the action of the transistor section 11. For this reason, the audio signal normally input from the input terminal 1 is output from the microphone amplifier 10 without being amplified. The audio signal output from the microphone amplifier 10 is recorded on the magnetic tape 9 from the audio head 8 via the recording/reproducing amplifier 6 and the recording amplifier 7. Therefore, only at the time of microphone input, the audio signal is amplified and high frequency noise is reduced.

Effects of the Invention As described above, according to the present invention, high-frequency noise during microphone input can be reduced at low cost by using a microphone amplifier that is built into a recording/playback IC but is not used. It can be lowered by a simple circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of a high frequency lowering microphone amplifier according to an embodiment of the present invention. 1... Normal input terminal, 2... Microphone input terminal, 3.
... Selector switch, 4... High frequency reduction amplifier, 1
0...Microphone amplifier, 11...Transistor part, 1
2... Capacitor. Agent Yoshihiro Morimoto Figure J-t77JJΦ2 Itsushi 124-1. M
l Town Wave Number I Mr. Ania')〉Tip 2 Tap Figure 2 7!0

Claims (1)

[Claims] 1. A microphone input terminal having a switch instruction circuit, a switch section that switches between a normal input terminal and a microphone input terminal in response to an instruction signal from the switch instruction circuit, and a switch section built in the recording/playback IC and receiving an instruction signal from the switch instruction circuit. An audio signal recording and reproducing device comprising: a microphone amplifier that operates to reduce high frequency noise input from a microphone input terminal via a switch unit.