JPH06133387A - Voice signal processing unit - Google Patents

Abstract

PURPOSE:To provide the voice signal processing unit able to input a voice signal with high definition even by a built-in microphone or an external microphone. CONSTITUTION:The processing unit is a unit which receives a voice signal by its built-in microphone 7 or an external microphone connecting to an external microphone connection terminal 18 and processes the inputted voice signal, and discriminates whether the inputted voice signal comes from the external microphone connecting to the external microphone connection terminal 19 or the built-in microphone 17 and selects the frequency characteristic of the inputted voice signal depending on the discrimination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal processing device for processing an audio signal input by a built-in microphone or an external microphone.

[0002]

2. Description of the Related Art In the present specification, a camera-integrated VTR capable of recording both an image pickup signal and an audio signal will be described below as an audio signal processing device.

The VTR with a built-in camera has been miniaturized in recent years,
Along with this, the mechanical distances between various motors that generate noise (for example, focus lens driving motors, zoom lens driving motors, VTR motors, etc.) and the built-in microphone inevitably become closer. Further, there is a limit to the reduction of driving noise of the motor and the like.

Therefore, when voice is recorded by the built-in microphone of the camera-integrated VTR thus miniaturized, the motor drive noise or the like which is not desired to be recorded is also recorded.

Therefore, a camera-integrated VTR has already been proposed in which the frequency characteristics and sensitivity of the built-in microphone and the characteristics of the audio signal processing circuit are changed to record the driving noise so that it is not heard.

In addition to the built-in microphone, the above-mentioned camera-integrated VTR is provided with an external microphone connection terminal for inputting voice from an external microphone.

[0007]

However, in the conventional camera-integrated VTR, when the voice is collected by the external microphone, the processing circuit of the voice signal collected by the built-in microphone is used as it is. Does not need to worry about drive / vibration noise generated from the inside of the camera, but changes the frequency characteristics etc. like the audio signal collected by the built-in microphone (attenuates the frequency range of drive / vibration noise). Therefore, there was a problem that high-quality voice cannot be recorded by an external microphone.

Under the circumstances, an object of the present invention is to provide an audio signal processing device capable of inputting a high-quality audio signal to both the built-in microphone and the external microphone.

[0009]

An audio signal processing apparatus according to the present invention is an apparatus for inputting an audio signal by a built-in microphone or an external microphone built in the apparatus and processing the input audio signal. Determining means for determining whether the input audio signal is from the built-in microphone or the external microphone, and frequency characteristic switching means for switching the frequency characteristic of the input audio signal according to the output of the determining means. And have.

[0010]

According to the above-mentioned invention, regardless of whether the voice is recorded by the built-in microphone or the external microphone, the high-quality voice can be input because the optimum frequency characteristic is switched according to the microphone in use.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A camera-integrated VTR according to an embodiment of the present invention will be described below.

FIG. 1 is a block diagram of a camera-integrated VTR of this embodiment.

In FIG. 1, 1 is an optical system including a focus lens, 2 is a shutter for adjusting a diaphragm, and 3 is C.
An image pickup device such as a CD, 4 is a video signal processing circuit for performing a predetermined signal process on a signal output from the image pickup device 3, and 5 is a recording process for performing a predetermined process for recording a video signal and an audio signal on the magnetic tape 7. Circuit, 6 magnetic head, 7 magnetic tape,
Reference numeral 8 denotes an AE control circuit for adjusting the shutter 2 using the output of the video signal output from the image sensor 3, and 9 denotes the optical system 1 using the output of the video signal output from the image sensor 3.
AF control circuit for adjusting the focus of the focus lens of
Reference numeral 0 is a motor for moving the focus lens of the optical system 1, 11 is a display processing circuit for multiplexing a title display and the like on an image pickup signal, 12 is an electronic viewfinder (hereinafter referred to as EVF) for displaying a picked-up image and the like. ), 13 is a drum motor, 14 is a drum servo, 15 is a capstan motor, and 16 is a cap servo.

Reference numeral 17 is a built-in microphone, and a DC voltage is applied to the output of the built-in microphone 17. Reference numeral 19 denotes a switch that switches in response to the connection of the connection terminal on the external microphone side to the external microphone connection terminal 18, 20 denotes a capacitor for removing a DC component, 21 denotes a DC voltage detection circuit, and a built-in microphone collects sound. It detects whether there is an audio pickup or an external microphone. 22 is an amplifier, 23 is a DC voltage detection circuit 2
1 is a frequency characteristic switching circuit that switches the frequency characteristic according to the output of 1. That is, the frequency characteristic switching circuit 22 is controlled by the DC voltage detection circuit 21.

A camera-integrated VT constructed as described above
A method of voice processing input by the R built-in microphone and voice processing input by the external microphone will be described.

First, a method for detecting whether an external microphone is connected to the external microphone terminal will be described.

FIG. 2 is a diagram for explaining a specific configuration of the switch 19.

In FIG. 2, when the external microphone connection terminal 18 is not connected to the external microphone connection terminal 18 on the camera side, the switch 19 is connected (FIG. 2A).
(See) and the audio signal of the built-in microphone is the capacitor 20.
Also, an audio signal is input to the DC voltage detection circuit 21.

When the connection terminal on the external microphone side is inserted into the external microphone connection terminal 18, the switch 19 is disconnected as shown in FIG. 2 (b), and the audio signal of the external microphone is detected by the capacitor 20 and the DC voltage detection. It is input to the circuit 21.

Next, FIG. 3 shows frequencies of voices to be taken in by the built-in microphone and the external microphone.

As shown in FIG. 3, when the voice is taken in by the built-in microphone, the mechanical driving noise is concentrated in the low range, so the low range frequency component is attenuated.

Further, since the cycle of the vertical synchronizing signal (about 60 Hz) and the cycle of the horizontal synchronizing signal (about 15.6 kHz) used in the internal video signal processing circuit affect the audio processing circuit, high frequency components Is attenuated by a notch filter,
Low frequency components are attenuated by HPF to drive noise,
The power supply noise (vibration noise) that occurs in the horizontal sync signal cycle is removed. That is, the frequency characteristic switching circuit 2
3 includes an HPF and a notch filter.

On the other hand, when the sound is taken in by the external microphone, it is not necessary to care about mechanical drive noise inside the camera and power supply noise due to air vibration. The frequency characteristic switching circuit 23 is controlled so as to obtain a flat characteristic.

In this embodiment, the DC voltage is applied to the output of the built-in microphone, but it may be determined by applying the DC voltage to the output of the external microphone.

Further, the frequency characteristic switching circuit 22 may be switched in association with the switch 19 described in FIG.

[0026]

As described above, the audio signal processing device of the present invention is a device for inputting an audio signal by the built-in microphone or the external microphone built in the device and processing the input audio signal. The input voice signal is determined by the built-in microphone or the external microphone, and the frequency characteristic of the input voice signal is switched according to the determination result. In either case of inputting voice with a microphone, high-quality voice input is possible because the optimal frequency characteristics are switched according to the microphone in use.

[Brief description of drawings]

FIG. 1 is a camera-integrated VTR according to an embodiment of the present invention.
It is a block diagram of.

FIG. 2 is a diagram illustrating a method of detecting an external microphone connection according to the present embodiment.

FIG. 3 is a diagram illustrating a difference in frequency characteristics of audio signals input and recorded by a built-in microphone and an external microphone.

[Explanation of symbols]

 17 Built-in Microphone 18 External Microphone Connection Terminal 19 Switch 21 DC Voltage Detection Circuit 22 Amplifier 23 Frequency Characteristic Switching Circuit

Claims (1)

[Claims] 1. A device for inputting a voice signal by a built-in microphone or an external microphone built in the device and processing the input voice signal, wherein the input voice signal is the built-in microphone. An audio signal processing device comprising: a judgment means for judging whether or not the external microphone is used, and a frequency characteristic switching means for switching a frequency characteristic of the input audio signal in accordance with an output of the judgment means.