JPH08293156A - Sound recorder - Google Patents

Abstract

PURPOSE: To provide a sound recorder capable of canceling an operation sound of a sound recording equipment with an active muffling technique and sound recording only a real sound recording objective sound. CONSTITUTION: The equipment 1 is provided with a sound collecting means 4, a means 9 recording the sound collected by the means 4 and a muffling means 7 superimposing a signal canceling the operation sound at a sound recording time on the sound collecting signal of the sound collecting means 4, and further, a pronounciation body 5 is provided as the operation sound, and an operation information guide sound as the operation sound from the pronounciation body 5 also not only a regular switch sound are made the objects of the muffling. This controller is constituted of e.g. the pronounciation body 5 pronouncing based on an operation information guide sound signal CS, a sound collecting microphone (Mic) 4, an adaptive control coefficient filter(CCF) 72 inputting the CS, processing it and forming a signal canceling that, an addition means 8 adding the output of the adaptive control coefficient filter 72 to the detection signal of the Mic 4, a renewal means 73 updating the coefficient of the CCF 72 from the detection signal of the Mic 4 so that the CS becomes minimum and a recording means recording the output signal of the addition means 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device having a recording function such as a video camera, and more particularly to a voice recording device thereof.

[0002]

2. Description of the Related Art In recent video cameras and the like, in order to prevent an operation switch sound from being mixed with a sound intended for recording, a switch with a small operation sound is used to make a mechanical system quiet.

Therefore, the operation feeling is sacrificed, and there arises a problem that an appropriate operation cannot be performed. On the other hand, in the technical field of air conditioners, etc.
A technique for actively canceling noise is disclosed in, for example, Japanese Patent Laid-Open No. Hei 4
-70200 gazette (H04R 3/00) etc. are disclosed.

[0004]

Therefore, a device is proposed in which a sounding body (for example, a buzzer, a speaker, or the like) produces an operation information cue sound as a substitute for the switch sound or the like.

According to this technique, since the switch sound, which is also seen as a conventional noise, is not used, the sound is slightly improved, but the problem that the true sound to be recorded cannot be obtained still remains. There is.

The present invention has been made in view of the above problems of the prior art. The operation information signal sound by the sounding body is used instead of the switch sound, and the operation information of the recording device is made by using the active muffling technology. It is an object of the present invention to provide a voice recording device capable of canceling a signal sound and recording only a true sound to be recorded.

[0007]

SUMMARY OF THE INVENTION Therefore, according to the present invention, sound collecting means for collecting sound in a device, recording means for recording sound collected by the sound collecting means, and operation information signal sound from a recording signal. And a sound deadening means for superimposing a signal to be canceled on the sound pickup signal of the sound collecting means.

If the operation explanation guidance voice sound is output from the sounding body instead of the operation information signal sound, the complexity of the operation function is eliminated. Here, the operation information cue sound is a cue sound (pippipip, etc.) that changes to a switch sound, and the operation explanation guidance sound is a voice guidance (a message such as pressing a button) of the operation method, which are collectively referred to as operation. We call it information guidance sound.

Specifically, as one embodiment, a sounding body which emits sound based on the operation information guide sound signal, a sound pickup microphone, and a signal which inputs and processes the operation information guide sound signal and cancels it are input. An adaptive control coefficient filter to be created, an addition means for adding the output of the adaptive control coefficient filter to the detection signal of the microphone, and the adaptive control coefficient filter to minimize the operation information guide signal from the detection signal of the microphone. An audio recording device is constituted by coefficient updating means for updating the coefficient and recording means for recording the output signal of the adding means.

In another embodiment, a sounding body which emits sound based on the operation information guide sound signal, a microphone for collecting sound, and the operation information guide sound signal are synchronously processed and prepared in advance. An audio recording device is constituted by memory means for storing a signal to be canceled, addition means for adding the output of the memory means to the detection signal of the microphone, and recording means for recording the output signal of the addition means.

[0011]

Operation: From the audio signal recorded by the sound collecting means, only the operation information guide sound is removed by the sound deadening means, and only the true sound to be recorded is recorded.

The muffling means may be a method of analyzing a voice mixed with an operation sound detected by the sound collecting means and feeding back the result to adjust the muffling signal of the muffling means, or a predetermined fixed method. A method of muting with a muting signal may be used.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the audio recording apparatus of the present invention is applied to a video camera will be described in detail below with reference to the drawings.

FIG. 1 is an external perspective view of a video camera.
In the figure, 1 is a camera body, 2 is a finder section, 3 is a lens section, 4 is a sound pickup microphone, and 5 is a sounding body for producing operation guidance information and the like.

Incidentally, switches for recording / playback and the like are collectively arranged on the back side which does not appear in the drawing, and all operation information signal sounds replacing the operation sounds of these switches are sounded from the sounding body 5. And

Next, an audio recording device mounted on the video camera will be described. FIG. 2 is a block diagram illustrating the principle of silencing operation sounds. In the figure, the signal CS output from the sounding body control signal creating unit 6 that creates the operation sound or the operation information guide sound emitted from the sounding body 5 is supplied to the sounding body 5 and the muffling means 7.

The sound pickup microphone 4 picks up both the sound to be recorded and the sound emitted from the sounding body 5 (transfer characteristic W between the sounding body and the microphone), and inputs the detection signal to the adding means 8.

The muffling means 7 produces a sound having the same sound pressure and volume as the sound emitted by the sounding body 5 and having an opposite phase (anti-phase transfer characteristic between the sounding body and the microphone-W) and inputs it to the adding means 8. .

As a result, the signal output from the adding means 8 becomes a signal of only the recording target sound from which the sound of the sounding body 5 is removed, and this is recorded in the recording means 9. Here, the anti-phase signal generated by the muffling means 7 may be a fixed signal determined in advance, or the sound pickup microphone 4 may be used.
It is also possible to use a signal that is adaptively adjusted so that the sound emitted by the sounding body is minimized from the actual sound generated by the sounding body detected in (1). (First Embodiment) A first embodiment relates to a method of canceling an operation sound by using a fixed antiphase signal, and its circuit block is shown in FIG.
Shown in

In FIG. 3, the signal CS output from the sounding body control signal generating section 6 is supplied to the sounding body 5, and the signal (0 or 1) is sent from the memory means 71 and the sound emitted by the sounding body 5. Are input to the memory means 71 so as to be synchronized.

When the memory means 71 receives the signal, the signal stored in the memory means 71 is transmitted. Next, the transmitted signal and the signal received by the microphone 4 are synchronized with each other by the early processing unit 10, and the addition result by the adding means 8 is set to zero.

The microphone 4 collects the sound of the transfer characteristic W emitted by the sounding body 5 together with the sound to be recorded, and inputs the collected sound signal to the adding means 8. Further, in the adding means 8, the signal from the memory means 71 is subtracted from the collected sound signal, and a signal containing only the sound to be recorded is output.

The output signal from the adding means 8 is recorded in the recording means 9. (Second Embodiment) A second embodiment relates to a method of canceling an operation sound by using a variable antiphase signal, and its circuit block is shown in FIG.
Shown in

In FIG. 2, the signal CS output from the sounding body control signal creating section 6 is supplied to the sounding body 5 and also input to the adaptive control coefficient filter section 72. The signal CS is filtered by the filter section 72 and becomes a signal for canceling the sound of the sounding body 5 having a negative transfer characteristic -W.

The microphone 4 collects the sound of the transfer characteristic W emitted by the sounding body 5 together with the sound to be recorded, and inputs the collected sound signal to the adding means 8. In the adding means 8, the signal from the filter section 72 is subtracted from the collected sound signal, and a signal containing only the sound to be recorded is output.

The output signal from the adding means 8 is recorded in the recording means 9. LMS (Least Mean Square) processing unit 7
Reference numeral 3 serves to vary and adjust the coefficient of the filter unit 72, and the updating of the coefficient is performed in advance so as to minimize the signal such as the operation sound from the sounding body 5 actually detected through the microphone 4 or recorded. Adjusted just before the start.

Although the second embodiment is superior to the first embodiment in that it can follow the change in the transfer characteristic between the sounding body and the microphone due to the change in the recording environment, etc.,
It is inferior to the first embodiment in that the circuit configuration becomes complicated and the product price cannot be kept low.

Therefore, the configuration of the first embodiment is rather suitable for a low-priced video camera having a simplified function, and the configuration of the second embodiment is suitable for a full-spec high-performance video camera.

[0029]

As described above, the present invention relates to a switch sound of a device which is recorded at the time of recording a voice by using the active muffling technology, or a switch sound to eliminate the switch sound and guide the operation by sound. Since it does not record the operation information guidance sound, it is possible to record only the sound to be recorded without worrying about simultaneous recording of operation sound, and to provide a voice recording device that can be expected to improve recording quality. It becomes possible.

In particular, when the present audio recording device is mounted on an AV device such as a video camera, a structure for canceling the operation sound of the device by using a fixed mute signal is suitable for a low-priced device having a simplified function, The one that can adjust the mute signal according to the change of the transfer characteristic between the microphone and the microphone is suitable for the full-spec high-performance equipment.

[Brief description of drawings]

FIG. 1 is an external perspective view of a video camera to which an audio recording device of the present invention is applied.

FIG. 2 is a circuit block diagram showing the principle of a voice recording device having an active muffling function.

FIG. 3 is a circuit block diagram of an embodiment of an audio recording device.

FIG. 4 is a circuit block diagram of another embodiment of the audio recording device.

[Explanation of reference numerals] 1 main body 2 finder section 3 lens section 4 sound pickup microphone 5 sounding body 9 recording means 10 synchronization signal processing section 71 memory means 72 adaptive control coefficient filter 73 coefficient updating section

Claims (4)

[Claims] 1. A sound collecting means for collecting a sound, a recording means for recording a sound collected by the sound collecting means, and a signal for canceling an operation sound at the time of recording the sound as a sound collecting signal of the sound collecting means. An audio recording device provided with a silencing means for superimposing. 2. The voice recording device according to claim 1, wherein a sounding body is provided, and an operation information guide sound as the operation sound is generated from the sounding body. 3. A sounding body that emits sound based on an operation information guide sound signal, a microphone for collecting sound, and an adaptive control coefficient filter that inputs and processes the operation information guide sound signal and creates a signal that cancels it. Adding means for adding the output of the adaptive control coefficient filter to the detection signal of the microphone; and coefficient updating means for updating the coefficient of the adaptive control coefficient filter so that the operation information guide signal is minimized from the detection signal of the microphone. A voice recording device comprising recording means for recording the output signal of the adding means. 4. A sounding body that produces a sound based on an operation information guide sound signal, a microphone for collecting sound, and a canceling signal that has been created in advance by synchronizing the operation information guide sound signal and storing the same. An audio recording device comprising: a memory means to be placed; an adding means for adding an output of the memory means to a detection signal of the microphone; and a recording means for recording an output signal of the adding means.