JP2002074673A - Voice recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of the seek noise to a voice signal recorded on a disk recording medium. SOLUTION: A voice signal processing circuit 32 is provided with a signal processing circuit 66 for receiving the voice signal produced by a microphone (not shown in the Figure) and applying the well-known signal process thereto for supplying to an amplifier 68 and a switch 70, the amplifier 68 for supplying the voice signal received from the signal processing circuit 66 to the switch 70 by attenuating it by a factor k, and the switch 70 for outputting either one of the voice signals received from the signal processing circuit 66 and the amplifier 68 on the basis of a control signal from a microcomputer (not shown in the Figure). The voice signal outputted from the switch 70 is recorded on a magneto-optical disk by the optical pickup. Then, the control signal outputting the voice signal received from the amplifier 68 is supplied to the switch 70 by the microcomputer at the time of seek operation of the optical pickup (not shown the Figure).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio recording apparatus, and more particularly to an audio recording apparatus which records an audio signal in each of a plurality of recording areas discretely distributed on a disk recording medium by an optical pickup.

[0002]

2. Description of the Related Art In a disk device of this type, when reading a predetermined signal from a disk recording medium or writing a predetermined signal, as shown in FIG. To access. When accessing the recording area, the seek operation moves the optical pickup in the radial direction of the magneto-optical disk 34 to reach the track where the target recording area exists. When the optical pickup moves by this seek operation, the tracking servo is off and the focus servo is on.

A tracking error signal (hereinafter referred to as a "TE signal") for controlling a tracking servo and a focus servo and a focus error signal (hereinafter referred to as an "FE signal").
As shown in FIG. 17A, a land track (shown in FIG. 17A) provided on the surface of the magneto-optical disk 36 is used.
L) in FIG. 17A or a groove track (FIG. 17)
Three laser beams 46a applied to G) in (A),
It is generated based on the reflected light of 46b and 46c. The laser beam reflected by the surface of the magneto-optical disk 36 is received by a photodetector 48 provided inside the optical pickup and provided with a plurality of light receiving elements 48a to 48h as shown in FIG.

The laser beam 46b is divided into four laser beams A, B, C and D, and irradiates the surface of the magneto-optical disk 36. The reflected beams of the laser beams A to D Light receiving element 48 corresponding to the alphabet
a, 48b, 48c and 48d, respectively.

Similarly, the laser beam 46a and the laser beam 4
6c is 2 of laser light E and F and laser light G and H
And the reflected light of each laser beam is E ~
The light receiving elements 48e and 48 corresponding to the alphabet of H
f, 48g, and 48h respectively receive light.

When the outputs from the light receiving elements 48a to 48h are represented by alphabets A to H, TE and FE are calculated by calculations based on equations (1) and (2), respectively.

[0007]

## EQU1 ## TE = {(A + B)-(C + D)}-α} (E
+ H)-(F + G)｝, where α ≒ 2.

[0008]

FE = (A + C)-(B + D)

[0009]

During a seek operation, the optical pickup exceeds a plurality of land tracks and groove tracks in the track width direction. Since the land track and the groove track have different reflectances, the laser light 4
Brightness and darkness occur in the spot formed by the reflected light 6b on the light receiving elements 48a, 48b, 48c and 48d. This light / dark changes as shown in FIG.
It changes as shown in FIG. The shaded portion in each of FIGS. 18A and 18B is the dark portion of the brightness (the same in FIG. 19).

As shown in FIG. 18, the spot shape is a perfect circle, and the center of the spot is located at the light receiving elements 48a, 48b, 4
The coincidence with the centers of 8c and 48d is an ideal state. Thus, when the spot is ideal, the value of the FE signal during the seek operation is always 0.

However, even when the beam spot on the magneto-optical disk 36 is ideally narrowed down due to an assembling error of the pickup optical system or the like, the sensor (light receiving element 48) can be used.
a, 48b, 48c and 48d) may not be in the ideal state. In this case, the brightness of the spot of the laser beam during the seek operation shown in FIG. 18 also affects the focus detection (focus error signal),
The focus error signal does not always become “0”.

As shown in FIG. 19, the spot of the laser beam in the actual disk drive is elliptical, and its center is located at the center of the sensor (light receiving elements 48a, 48b, 48c and 48c).
It is shifted from the center of d). The shape of the spot is shown in FIG.
Since the values change as shown in (A) and (B), the values of (A + C) and (B + D) in Expression 2 are not equal. Therefore, a signal waveform other than “0” appears in the FE signal during the seek operation. Further, since the center of the spot is shifted, the difference between the values of (A + B) and (B + D) is further increased, and the signal waveform appearing in the FE signal is further increased.

Therefore, in an actual disk device, the FE signal at the time of the seek operation includes a signal waveform that should not be generated originally. This signal waveform that should not occur originally and is included in the FE signal is called a “TE leakage signal”. If the FE signal contains the TE leakage signal, the optical pickup vibrates greatly up and down by the focus servo based on the FE signal, and noise is generated.

The optical pickup is connected to a sled motor in a rack and pinion state or the like. During the seek operation, the rotation of the sled motor is transmitted to the rack and pinion state, whereby the optical pickup is moved in the radial direction (inner circumferential direction and outer circumferential direction) of the magneto-optical disk 36 (sled movement). Therefore, during the seek operation, not only noise due to the vibration of the optical pickup, but also noise due to the rotation of the sled motor and the operation in the rack and pinion state are generated.

For this reason, in the conventional audio recording apparatus, there is a problem that noise generated during the operation of the sled is picked up by the microphone when recording the audio, and the noise is mixed with the audio signal to be originally recorded.

In order to solve this problem, there has been an audio recording apparatus which employs a method of blocking vibrations generated from a noise source from being directly transmitted to a microphone. As a method of shutting off the noise source and the microphone, there is a method of attaching the microphone to the housing of the audio recording device via a cushioning material such as rubber or sponge.

[0017]

However, in a method of attaching a microphone to a housing of an audio recording device via a buffer material as in a conventional audio recording device, it is not possible to prevent noise caused by transmission of vibration to the microphone. Although it was possible, it was not possible to remove the noise generated when the noise generated from the noise source was picked up by the microphone.

Therefore, a main object of the present invention is to provide an audio recording apparatus capable of reducing the influence of a seek noise picked up by a microphone on a recorded audio signal.

[0019]

SUMMARY OF THE INVENTION The present invention relates to an audio recording apparatus for recording an audio signal in a plurality of free areas discretely formed on a disk recording medium by an optical pickup, and continuously taking in the audio signal from the outside. Microphone, writing means for temporarily writing the audio signal captured by the microphone to the buffer, and moving means for moving the optical pickup to record the audio signal stored in the buffer in each free space, the writing means, An audio recording apparatus characterized by including an attenuating means for attenuating an audio signal when the optical pickup is moved by the moving means.

[0020]

According to the present invention, the signal level of the portion of the audio signal recorded on the disk recording medium that includes seek noise is attenuated. That is, the microphone continuously captures the audio signal from the outside, and the writing unit temporarily writes the audio signal captured by the microphone into the buffer. The moving means moves the optical pickup in order to record the audio signal stored in the buffer in each free area, and the attenuation means attenuates the signal level of the audio signal when the optical pickup moves by the moving means. Therefore, when the optical pickup moves, the audio signal is attenuated.

In the preferred embodiment of the present invention, whether or not to attenuate the audio signal is determined based on the movement of the optical pickup and the level of the audio signal. That is, the determining means determines the level of the audio signal captured by the microphone, and the attenuating means attenuates the audio signal in accordance with the determination result of the determining means.

In another preferred embodiment of the present invention, the first
And the second method attenuates the signal level of the audio signal. That is, the first attenuating means attenuates the signal level of the audio signal irrespective of the frequency of the audio signal as a first method, and the second attenuating means attenuates only a predetermined frequency band of the audio signal as a second method. .

Further, the attenuation rate by the first attenuation means may be changed according to the signal level of the audio signal. Further, it is desirable that the predetermined frequency band includes a frequency band of noise generated due to the movement of the optical pickup, and that the frequency band to be attenuated is changed according to the signal level of the audio signal.

In another aspect of the present invention, it is determined whether to attenuate the signal level of the audio signal based on the signal for a predetermined period obtained from the audio signal. That is, the comparing means compares the signal level of the audio signal with the first threshold value off the predetermined period, and the measuring means measures the level decrease time during which the signal level of the audio signal continuously becomes equal to or less than the first threshold value. The attenuating means attenuates the audio signal when the level reduction time of the audio signal exceeds the second threshold.

In still another aspect of the present invention, it is determined whether to attenuate the signal level of the audio signal based on the average level of the signal for a predetermined period obtained from the audio signal. That is, the average level of the audio signal of the determination unit for a predetermined period is repeatedly calculated, and the attenuation unit attenuates the audio signal when the average level becomes equal to or less than the third threshold.

[0026]

According to the present invention, the signal level of the audio signal during the seek operation is attenuated and recorded on the disk recording medium. Therefore, the influence of the seek noise on the audio signal recorded on the disk recording medium can be reduced.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0028]

Embodiment 1 Referring to FIG. 1, in this embodiment, a digital camera 10 constitutes an audio recording device. The digital camera 10 includes a focus lens 12 and a microphone 30. The light image of the subject that has passed through the focus lens 12 is incident on the light receiving surface of the CCD imager 14. On the light receiving surface, a camera signal (video signal) corresponding to the incident light image is generated by photoelectric conversion.

The timing generator (TG) 24 includes:
When a processing command is given from the system controller 26, camera signals are repeatedly read from the CCD imager 14 at a predetermined frame rate. The read camera signal is converted into a digital signal by an A / D converter 18 through well-known noise removal and level adjustment in a CDS / AGC circuit 16.

On the other hand, the audio signal processing circuit 32 acquires an audio signal from the microphone 30 when a processing command is given from the system controller 26. The acquired audio signal is converted into a digital signal by the A / D converter 34 through predetermined signal processing described later.

The audio signal circuit 32 is specifically shown in FIG.
It is configured as shown in FIG. The audio signal output from the microphone 30 is given to the switch 70 directly and via the amplifier 68 through well-known signal processing by the signal processing circuit 66. The switch 70 receives a signal (hereinafter, referred to as a “normal signal”) from a signal processing circuit 66 or a signal (hereinafter, referred to as a “normal signal”) from a signal processing circuit 66 in response to a control signal from a microcomputer (Digital Signal Processor) 56 described later. (Referred to as “correction signal”) and outputs the same to the A / D converter 34. The amplifier 68 amplifies the audio signal supplied from the signal processing circuit 66 by a factor of k and outputs it. Here, the coefficient k is a value smaller than 1, and preferably a value in a range of 1/2 to 1/10. Therefore, the amplifier 68 functions as an attenuator.

A / D converter 18 and A / D converter 34
The recording signal converted into a digital signal by the above is input to the recording signal creation circuit 20. Input camera signal and audio signal (hereinafter referred to as “recording signal”)
Is output to the buffer memory 22 as a recording signal on which predetermined signal processing has been performed. The recording signals stored in the buffer memory 22 are appropriately read by a microcomputer (Digital Signal Processor) 56 that controls a disk drive system.

The system controller 26 receives a shutter signal from the shutter button 28b and gives a processing command to the timing generator (TG) 24 and the audio signal processing circuit 32. The shutter signal is also given to the microcomputer 56 by the system controller 26.

The disk drive system includes an optical pickup 42. The optical pickup 42 is an optical lens (objective lens)
The objective lens 50 is supported by the actuator 44. The actuator 44 includes a tracking actuator and a focus actuator. The laser light output from the laser diode 46 is converged by the objective lens 50, and the ASMO (Adva
The recording surface of a magneto-optical disk (MO disk) 36 such as a nced Storage MagnetoOptical disk is irradiated. As a result, the desired signal is
And a desired signal is read from the recording surface.

The magneto-optical disk 36 is a disk that can record on land tracks and groove tracks. The optical pickup 42 is connected to the sled motor 38 by, for example, a rack and pinion state 40, and its position is moved in the radial direction (outer peripheral direction and inner peripheral direction) of the magneto-optical disk 36 (seek operation).

The reflected laser light reflected on the recording surface of the magneto-optical disk 36 passes through the same objective lens 50 and irradiates the photodetector 48. The output of the photodetector 48 is input to an FE signal detection circuit 52 and a TE signal detection circuit 54, and the FE signal detection circuit 52 outputs a focus error signal (F
The tracking error signal (TE signal) is detected in the E signal) and the TE signal detection circuit 54, respectively. F detected
The E signal and the TE signal are supplied to the A /
The signals are supplied to a core (not shown) of the microcomputer 56 via a D converter (not shown).

The photodetector 48 is specifically shown in FIG.
It is configured as shown in FIG. The photodetector 48 has four regions A to D provided at the center and regions F and E and regions G and H provided above and below the four regions A to D. Each of the regions A to H is controlled by the light detection elements 48a to 48h. It is formed. The laser light emitted from the laser diode 46 is diffracted by a diffraction grating (not shown), and the three laser lights 46a, 46b,
Reference numeral 46c irradiates the recording surface of the magneto-optical disk 36 through the objective lens 50. That is, as shown in FIG. 17A, with respect to the rotation direction (tangential direction) of the magneto-optical disk 36, the laser light 46b corresponding to the regions A to D is the center, and the regions E and F The corresponding laser beam 46a and the laser beam 4 corresponding to the regions G and H
6c is irradiated. The laser beam 46b corresponding to the regions A to D is the main beam, and the laser beams 46a and 46c corresponding to the regions E and F and the regions G and H.
Is a sub beam. The reproduction signal (recording signal) and the FE signal are extracted from the main beam. Also,
The TE signal is extracted from the main beam and the sub beam.

The FE signal and the TE signal extracted from the main beam and the sub beam are supplied to the microcomputer 56 as described above. The microcomputer 56 performs predetermined processing on the given FE signal and TE signal, and generates a focus actuator control signal from the FE signal, and a tracking actuator control signal and a thread control signal from the TE signal. Each of the generated control signals is converted into an analog signal by a D / A converter (not shown) provided in the microcomputer 56, and the focus actuator control signal, the tracking actuator control signal, and the thread control signal are converted into a focus actuator (FACT) drive circuit 60. , Focus actuator (TA
CT) drive circuit 62 and thread (SLED) drive circuit 64
Respectively.

Focus actuator drive circuit 60
Adjusts the focus of the objective lens 50 by moving the position of the actuator 44 in the axial direction of the magneto-optical disk 36. The tracking actuator drive circuit 62 moves the position of the actuator 44 in the radial direction (tangential direction) of the magneto-optical disk 36 to
Follow a land track or a groove track.

Here, the focus actuator control signal is generated based on the FE signal. As described above, the FE signal during the seek operation includes the TE leakage signal. Because of this TE leakage signal, the amplitude of the FE signal during the seek operation is larger than it should be. Therefore, the focus actuator control signal generated at the time of the seek operation is a signal for causing the position of the optical pickup 42 in the axial direction of the magneto-optical disk 36 to perform the focus operation more than necessary. The optical pickup 42 vibrates greatly due to excessive focus movement during the seek operation, and noise is generated.

The sled drive circuit 64 drives the sled motor 38 connected to the optical pickup 42 through the rack and pinion state 40 to drive the optical pickup 42
Is moved in the radial direction (tangential direction) of the magneto-optical disk 36 (seek operation).

As described above, during the seek operation of the optical pickup 42, noise is generated by the vibration of the optical pickup 42 caused by the TE leakage signal included in the FE signal and the operation of the sled mechanism.

In the digital camera 10 of this embodiment,
By attenuating the signal level of the audio signal output from the microphone 30, the influence of the noise at the time of the seek operation included in the audio signal on the audio signal to be originally recorded is reduced.

The microcomputer 56 of the digital camera 10 according to the present embodiment executes the processing of the procedure shown in the flowcharts of FIGS. 4 and 5 show that the digital camera 10 transmits the recording signal to the magneto-optical disk 3.
6 shows the processing for recording.

Power supply for digital camera 10 (not shown)
Is input from the system controller 26 to the microcomputer 56. When receiving the activation signal, the microcomputer 56 first turns on the focus actuator (FACT) drive circuit 60 in step S1, and turns on the tracking actuator (TACT) drive circuit 62 in step S3.

In step S5, it is determined whether or not the disk drive system is in the recording mode. Digital camera 10
When the operator sets the mode switching button 28a to the recording mode, a mode switching signal to the recording mode is given from the system controller 26 to the microcomputer 56, and the disk drive system shifts to the recording mode. When the disk drive system shifts to the recording mode, it is determined in step S5 that the mode is the recording mode.

In step S7, the TOC (Table of Contents) is read from the magneto-optical disk 36 and a free area table as shown in FIG.
om access memory) 58. This free area table corresponds to the free areas of the magneto-optical disk 36 shown in FIG. 16, and the head address and the recording capacity of each free area are held.

When the operator depresses the shutter button 28b in the recording mode, a shutter signal is given to the microcomputer 56 via the system controller 26.
When the shutter signal is given to the microcomputer 56, step S
At 9 it is determined that the shutter button 28b is on. When it is determined that the shutter button 28b is in the ON state, the microcomputer 56 switches the switching control signal to the switch 70 (FIG. 2) included in the audio signal processing circuit 32 in step S11.
(A), and sets the audio signal output from the audio signal processing circuit 32 to a normal signal.

Next, the microcomputer 56 determines in step S13 whether or not the buffer memory 22 is empty, that is, whether or not data to be recorded (hereinafter referred to as "recorded data") still exists in the buffer memory 22. I do. The absence of data in the buffer memory 22 is a data recording end condition. If it is determined that there is data (recording data) to be recorded in the buffer memory 22, at step S17, an empty area for recording data is allocated to the DRAM.
The determination is made based on the free area table recorded in No. 58 (see FIG. 13). As a method of determining a free area, a method of selecting a free area having a large free capacity can be considered.

In step S19, it is determined whether or not the amount of data stored in the buffer memory 22 is equal to or less than a predetermined threshold. Here, the predetermined threshold value is determined based on, for example, the data accumulation speed in the buffer memory 22, the capacity of a free area for recording data, the writing speed, and the like so that the data does not overflow or deplete in the buffer memory 22. Value.

When it is determined that the amount of data stored in the buffer memory 22 is equal to or larger than the threshold, the tracking actuator drive circuit 62 is turned off in step S23. Then, in step S25, the thread drive circuit 64 is turned on, and the optical pickup 42 is threaded toward a track having an empty area (determined in step S17) (seek operation).

In step S27, the microcomputer 56 supplies the switching control signal to the switch 70 of the audio signal processing circuit 32, and outputs the audio signal output from the audio signal processing circuit 32 to the audio signal attenuated by a factor k by the amplifier 68. Signal (hereinafter, referred to as “correction signal”). Therefore, the audio signal processing circuit 32 outputs an audio signal whose signal level has been attenuated.

In step S29, it is determined whether or not the optical pickup 42 has reached the target track. If it is determined that the movement has been reached, the thread (SLED) drive circuit 64 is turned off in step S31 to end the seek operation, and in step S33, the tracking actuator drive circuit 6
2 is turned on.

Further, in step S35, the microcomputer 56 supplies the switching control signal to the switch 70 of the audio signal processing circuit 32, and outputs the signal output from the audio signal processing circuit 32 to the audio signal output from the signal processing circuit 66 (hereinafter, referred to as the signal). Switch to "normal signal").

Then, in step S37, the microcomputer 56 acquires a recording signal corresponding to the free space of the recording area (determined in step S17) from the buffer memory 22 and records it in the free area. When recording to the empty area is completed, DR
Free area table recorded in AM 58 (see FIG. 13)
Is updated in step S39.

When the update of the free area table is completed, the flow returns to step S13 to determine again whether or not the buffer memory 22 is empty. If recording data remains in the buffer memory 22, a free area is determined again in step S17, and the processing from step S19 to step S37 is repeated to record the remaining recording data.

In step S19, the buffer memory 2
If it is determined that the amount of print data stored in the storage unit 2 is smaller than the threshold, it is determined in a step S21 whether or not the shutter button 28b is off. Shutter button 2
If 8b is in the ON state, the process returns to step S19 to determine again whether the amount of recording data is equal to or larger than the threshold value. On the other hand, when the shutter button 28b is in the off state, the recording data is not accumulated any more in the buffer memory 22, so that the process proceeds to step S23 and thereafter to write the recording data remaining in the buffer memory 22.

When the recording data is recorded, it is determined in step S13 that the buffer memory 22 is empty,
The TOC of the magneto-optical disk 36 is updated in step S15 based on the free area table recorded in the RAM 58, and the process returns to step S5 to end the data recording process.

In the digital camera 10 of this embodiment, the signal level of the sound signal during the seek operation of recording the recording signal on the magneto-optical disk 36 is attenuated, so that the signal level of the portion including noise during the seek operation of the audio signal is reduced. Be lowered. Therefore, seek noise included in the audio signal recorded on the magneto-optical disk 36 becomes less noticeable.

[Second Embodiment] In the digital camera 10 of the second embodiment, not only the signal level of the audio signal is reduced during the seek operation, but also the frequency of the seek noise in the frequency band of the audio signal is reduced by using a filter circuit. Only the frequency band other than the frequency band containing the most is passed.

The configuration of the digital camera 10 of the second embodiment is different from that of the digital camera 10 of the first embodiment (FIG. 1) only in the configuration of the audio signal processing circuit 32, and the other configurations and operations are the same. Audio signal processing circuit 3
Only the configuration 2 will be described.

The audio signal processing circuit 32 is specifically shown in FIG.
The configuration is as shown in FIG. The audio signal output from the microphone 30 is supplied to an amplifier 68 and a switch 70 through known signal processing by a signal processing circuit 66. The amplifier 68 amplifies the applied audio signal by a factor of k and supplies the amplified audio signal to the filter circuit 72. Here, the value of the coefficient k is a value of 1 or less. Therefore, the amplifier 68 functions as an attenuator. When the value of the coefficient k is 1, the correction signal is a signal obtained by adding only the filter effect of the filter circuit 72 to the audio signal output from the microphone 30.

The filter circuit 72 includes a low-pass filter (L
PF), and passes only frequencies below the frequency band that includes many seek noise frequencies to the switch 70. The frequency of the seek noise is 6 kHz to 7 kHz,
It is preferable that the filter circuit (LPF) 70 passes only a frequency band of 2 kHz or less.

In the digital camera 10 of this embodiment, the signal level of the audio signal is attenuated during the seek operation for recording the recording signal on the magneto-optical disk 36, and the frequency band of the seek noise is cut off. Therefore, the seek noise included in the audio signal recorded on the magneto-optical disk 36 becomes less noticeable.

The filter circuit 70 is not limited to a low-pass filter, but may be constituted by a band rejection filter (BEF). At this time, the filter circuit 70
7 kHz frequency band is cut.

[Embodiment 3] The noise included in the audio signal is
It becomes more noticeable when the level of the audio signal to be originally recorded is low. Therefore, in the digital camera 10 of the third embodiment, the audio signal output from the audio signal processing circuit 32 is switched to the correction signal only during the seek operation and when the audio signal level is low. Note that the time when the level of the audio signal is low indicates a time when the level of the audio signal is lower than a predetermined threshold for a predetermined period (time interval “T”).

The configuration of the digital camera 10 of the third embodiment is the same as the configuration of the digital camera 10 of the second embodiment except for the configuration of the audio signal processing circuit 32. The audio signal processing circuit 32 is specifically configured as shown in FIG. The audio signal processing circuit 32 of FIG. 3A is different from the audio signal processing circuit 32 of the second embodiment (FIG. 2B) in that the output of the audio signal processing circuit 66 is provided to the microcomputer 56. The circuit 32 includes an amplifier 68 and a filter circuit 72. The function of the filter circuit 72 is LPF or BEF.) The microcomputer 56 determines switching of the output of the audio signal processing circuit 32 (normal signal and correction signal) based on the audio signal obtained from the signal processing circuit 66, and gives the determination result to the switch 70.

The microcomputer 56 in the digital camera 10 according to the third embodiment executes the processes shown in the flowcharts of FIGS. 6 and 7 show processing relating to recording of a recording signal of the disk drive system (hereinafter, referred to as “main routine”), and the flowchart of FIG. 8 is output from the audio signal processing circuit 32. This is processing related to the determination of switching of the audio signal (hereinafter, referred to as a “switching determination routine”). The main routine (FIGS. 6 and 7) and the switching determination routine (FIG. 8) are executed independently and in parallel by the microcomputer 56.

The processing of the main routine shown in FIGS. 6 and 7 is the same as that of the first embodiment except that a determination portion (step S71 in FIG. 6) for switching the audio signal output from the audio signal circuit 32 is added. This is almost the same as the processing shown in FIGS. Therefore, the switching determination routine of FIG. 8 will be mainly described.

The microcomputer 56 first turns off the switching flag in step S101, and turns off the timer flag in step S103. Here, the switching flag is a flag for holding a determination result of whether to switch the output of the audio signal circuit 32 from the normal signal to the correction signal.
The timer flag is a flag for holding a state as to whether or not a timer for counting the time during which the output of the signal processing circuit 66 satisfies a predetermined condition has started.

Next, the microcomputer 56 has a signal processing circuit 66.
From the audio signal corresponding to time ΔT (hereinafter “unit signal”).
) Is obtained in step S105, and it is determined in step S105 whether the signal level of the obtained unit signal is equal to or less than the threshold.
The judgment is made at 107. Here, the threshold is, for example, microphone 3
0 is about 1/10 of the maximum range. Hereinafter, this threshold is referred to as “M ₁ ”. The time ΔT is a time corresponding to the minimum signal that can be handled by the microcomputer 56.

[0072] When the signal level of the unit signal is higher than M ₁ determines whether the timer flag is ON at step S121. At this time, since the timer flag is in the OFF state, the process returns to step S105, and the next unit signal is obtained from the signal processing circuit 66.

[0073] On the other hand, when the signal level of the unit signal is determined to be M ₁ or less in step S107, it is determined whether the timer flag is ON at step S109. Since the timer flag is currently off, the timer flag is turned on in step S111, and the timer (up counter) is started in step S113 (t _{1 in} FIGS. 14A and 14B). Although not shown in the flowchart, the microcomputer 56 counts the timer after starting the timer.

Next, in step S115, the switching flag is set.
Determine if it is on. Switching flag is on
Since the state is not the state, the value indicated by the timer in step S117 is
"T _thre("Threshold")
You. Where the value T_threIs the time as the threshold value and is 2-3
Is about a few seconds. The value indicated by the timer is T_threSmaller than
If not, the setting of the switching flag in step S119 is performed.
Skip to step S105, and repeat the next unit signal.
Get the issue. Then, the obtained unit signal is set in step S1
07 and M₁If it is determined that it is larger than
Determine if the timer flag is on in 1
You. When the timer flag is on,
In step S123, the timer is reset, and in step S12
The timer flag is turned off at 5 (t in FIG. 14A).
_Two). Then, in step S127, the switching flag is turned on.
Is determined. At this time, the switching flag is set to off.
The switching flag is cleared in step S129.
A is skipped and the process returns to step S105.

On the other hand, if it is determined in step S117 that the value indicated by the timer is equal to or greater than T _thre , the switching flag is turned on in step S119 (t _{2 in} FIG. 14B), and the _flow returns to step S105. Once the switching flag is turned on, the value of the newly acquired unit signal at step S105, switching flag until it is determined again greater than the threshold value M ₁ in step S107 remains in the ON state.

[0076] When the value of the unit signal is determined to be greater than M ₁ in step S107, it is determined whether the timer flag is ON at step S121. FIG.
In t ₃ of 4 (B), resets the timer from the timer flag is ON at step S123, to turn off the timer flag at step S125. Further, in step S127, it is determined whether or not the switching flag is on. Similarly, at t ₃ in FIG. 14B, since the switching flag is in the on state, step S 129 is performed.
The switch flag is turned off to return to step S105. Similarly, in the switching determination routine, the setting of the ON state and the OFF state of the switching flag is repeated according to the signal level of the audio signal output from the signal processing circuit 66.

In the processing of the main routine (FIGS. 6 and 7), the output from the audio signal processing circuit 32 is switched based on the determination result (value of the switching flag) in the switching determination routine. Specifically, when it is determined in step S69 of FIG. 6 that the capacity of the recording signal stored in the buffer memory 22 is equal to or larger than the threshold value, or when it is determined in step S71 that the shutter button 28b is in the off state, In step S73, it is determined whether or not the switching flag is on. If the switching flag is on, the microcomputer 56 supplies a switching control signal to the switch 70 (see FIG. 3A) included in the audio signal processing circuit 32 in step S75 to correct the output of the audio signal processing circuit 32. Switch to signal. On the other hand, if the switching flag is off, step S
Skip the signal switching at 75 and execute the subsequent processing.

As described above, the digital camera 1 according to the third embodiment
At 0, the audio signal output from the signal processing circuit 66 is constantly monitored. Then, it is determined whether or not the level of the audio signal is equal to or lower than the predetermined level for a predetermined time, and the ON / OFF state of the switching flag is set based on the determination result. The value set in the switching flag thus determined is referred to only during the seek operation, and if the state of the switching flag is on, the value output from the audio signal processing circuit 32 is switched to the correction signal. Therefore, the audio signal is switched to the correction signal only during the seek operation and when the level of the audio signal is low, that is, when the influence of the seek noise becomes strong and the audio signal needs to be corrected.

The method of determining whether or not to switch the audio signal output from the audio signal processing circuit 32 (the condition for setting the switching flag to the ON state) is based on the fact that the signal level of the audio signal is kept at a predetermined level (as described above). _Judgment may be made based on various methods, without being limited to the case where the difference is equal to or less than the predetermined threshold (M ₁ ) over T _thre ). For example, the determination may be made based on whether or not the average signal level of the audio signal corresponding to the predetermined time interval (T) is equal to or less than a predetermined threshold.

At this time, the microcomputer 56 executes the switching determination routine shown in the flowchart of FIG. 9 instead of the switching determination routine shown in the flowchart of FIG. That is, only the switching flag setting processing method is different from the above-described embodiment (Embodiment 3).
The processes shown in the flowcharts of FIGS. 6 and 7 are common. Therefore, only the switching determination routine for setting the switching flag will be described.

First, in step S131 in FIG. 9, the switching flag is turned off and initialization is performed. Next, the microcomputer 56
In step S133, the audio signal corresponding to the time interval T is taken into the DRAM 58 from the signal processing circuit 66, and the time interval "T" taken into the DRAM 58 in step S135.
Calculate the average signal level of the corresponding audio signal. Note that the value of the time interval T may be the same as the value of the threshold value T _thre . Then, in a step S137, it is determined whether or not the average signal level is equal to or less than a predetermined threshold. Here, the predetermined threshold is, for example, about 1/20 of the output range of the microphone 30. This threshold is hereinafter referred to as “M ₂ ”.

[0082] If it is determined that the average signal level is the threshold value M ₂ or less, set the switch flag to the ON state in step S139. Then, in step S141, the signal processing circuit 6
6, an audio signal (unit signal) corresponding to the time ΔT is obtained, and the process returns to step S135 to calculate the average signal level of the audio signal again. Here, the audio signal used for calculating the average level of the audio signal is an audio signal corresponding to the time interval T including the audio signal of ΔT newly acquired in step S141. Therefore, the second step S13
In 5, the average signal level of the audio signal corresponding to the time ΔT to the time T + ΔT is calculated.

[0083] On the other hand, when the average signal level in step S137 is determined to be higher than the threshold value M _2, set off state switching flag in step S143 (to set off state switching flag in the case of off-state), step In S141, an audio signal (unit signal) corresponding to the time ΔT is obtained,
Returning to step S137, the average signal level of the audio signal is calculated again.

As described above, the switching decision shown in the flowchart of FIG.
In the constant routine, it corresponds to the time interval T updated by ΔT
The average signal level of the audio signal is calculated sequentially, and the calculation result
Is M _TwoTurn on the audio signal switching flag when
State.

In the main routine shown in the flow charts of FIGS. 6 and 7, only during the seek operation (thread operation), the value set in the switching flag in step S73 of FIG. 6 is referred to. When the switching flag is on, the audio signal output from the audio signal processing circuit 32 is switched to the correction signal in step S75. When the thread drive circuit is turned off in step S83 and the seek operation ends, the audio signal is switched to the normal signal in step S85.

As described above, in the digital camera 10 that executes the switching determination routine shown in the flowchart of FIG. 9, the switching between the normal signal and the correction signal is determined based on the average of the signal levels. It is possible to more stably and appropriately switch the output of the audio signal than the digital camera 10 that executes the switching determination routine shown.
Note that a weighted average may be used as a method for calculating the average of the signal levels.

As described above, in the digital camera 10 according to the third embodiment, the audio signal output from the microphone 30 is constantly monitored, and the average signal level of the audio signal during the seek operation and for a certain period of time is lower than the predetermined threshold. Only when low
While attenuating the signal level of the audio signal to be recorded,
Cuts the frequency band corresponding to the frequency of the seek noise. Therefore, since the audio signal is corrected only when the audio signal level is low and the influence of the seek noise is large,
There is no danger of removing information contained in the audio signal more than necessary.

Although the above-described audio signal processing circuit 32 in the third embodiment includes both the amplifier 68 and the filter circuit 72, the audio signal processing circuit 32
8 or a filter circuit 72. Further, the filter circuit 72 may be constituted by either a low-pass filter or a band rejection filter.

[Fourth Embodiment] The digital camera 10 according to the fourth embodiment changes the degree of correction of an audio signal according to the signal level of the audio signal output from the microphone 30. The digital camera 10 according to the fourth embodiment differs from the digital camera 10 according to the third embodiment only in the configuration of the audio signal processing circuit 32. Other configurations are the same as those of the digital camera 10 according to the third embodiment.
Is the same as The audio signal processing circuit 32 of the fourth embodiment is specifically configured as shown in FIG. In the audio signal processing circuit 32 of this embodiment, as shown in FIG. 3B, not only the switch 70 but also the amplifier 68 and the filter circuit 72 are controlled by a control signal from the microcomputer 56. The microcomputer 56 changes the attenuation rate (the value of the coefficient k) of the amplifier 68 and the cutoff frequency of the filter circuit 72 (LPF) based on the output level (audio signal level) of the signal processing circuit 66. For other points, Example 3
Is the same as that of the digital camera 10.

The microcomputer 56 in the digital camera 10 according to the fourth embodiment executes the processing shown in the flowcharts of FIGS. 10 and 11 show a process (main routine) relating to recording of a recording signal of the disk drive system. The flowchart in FIG. 12 is a process (switching determination routine) related to determination of switching of the audio signal output from the audio signal processing circuit 32. The main routine (FIGS. 10 and 11) and the switching determination routine (FIG. 1)
2) is executed independently and in parallel by the microcomputer 56.

The processing of the main routine (FIGS. 10 and 11) is performed when the switching flag is determined to be in the ON state, and the cutoff frequency (fc) and the attenuation factor (k) set in the switching determination routine are determined. The processing is the same as that of the main routine shown in the flowcharts of FIGS. 6 and 7 except that the values are set in the amplifier 68 and the filter circuit 72. Therefore, the switching determination routine of FIG. 12 will be mainly described.

First, in step S201, the switching flag is turned off and initialization is performed. Next, the microcomputer 56 acquires an audio signal corresponding to the time interval T from the signal processing circuit 66 (see FIG.
In step S205, the average signal level of the audio signal corresponding to the time interval T captured in the DRAM 58 is calculated. The value of the average signal level calculated at this time is referred to as “Aav
e ". Then, in step S207, it is determined whether or not the average signal level is equal to or less than a predetermined threshold. Here, the predetermined threshold value is the same value as in the third embodiment, M ₂
And

[0093] If it is determined that the average signal level is the threshold value M ₂ or less, the attenuation factor k of the amplifier 68 at step S209
Determine the value of (coefficient k). The value of the coefficient k is shown in FIG.
It is determined based on a predetermined rule as shown in FIG.
As shown in FIG. 15A, the value of the coefficient k is determined in step S2.
It is given by a function of the average value Aave of the signal level calculated in 05. As shown in FIG. 15A, as the value of Aave increases, the value of coefficient k also gradually increases, and when the value of Aave exceeds a certain value, the value of coefficient k becomes a constant value “1”. Therefore, as the value of Aave increases, the attenuation rate decreases. In the graph of FIG. 15A, the value of the coefficient k is equal to or greater than “0”, but may include “0”. Although the function shown in FIG. 15A changes linearly, it may be a function that changes in a curve, and it is desirable to determine the function according to the characteristics of the signal processing system of the digital camera 10.

Next, the value of the cutoff frequency (fc) of the filter circuit (LPF) 72 is determined in step S211. The value of the cutoff frequency (fc) is also determined based on a predetermined rule as shown in FIG. FIG.
As shown in (B), the value of the cutoff frequency (fc) is given by a function of the average value Aave of the signal levels calculated in step S205. As shown in FIG. 15B, the cutoff frequency (fc) changes from the frequency “fL” to the frequency “f”.
H ”, and the value of the cutoff frequency gradually increases as the value of Aave increases. However, when the value of Aave becomes a certain value or more, the value of the cutoff frequency becomes a certain value “fH”. Although the function shown in FIG. 15B is a function that changes linearly, the function for determining the cut-off frequency may be a curved function, and may be adapted to the characteristics of the signal processing system of the digital camera 10. It is desirable to decide.

When the value of the coefficient k and the value of the cutoff frequency are determined, the switching flag is set to the on state in step S213.

In step S215, the microcomputer 56 acquires an audio signal (unit signal) corresponding to the time ΔT from the signal processing circuit 66, and returns to step S205. Step S
At 205, the average signal level of the audio signal corresponding to the time interval T is calculated again. Here, the audio signal used for calculating the average signal level Aave is an audio signal corresponding to the time interval T including the audio signal of ΔT newly acquired in step S215. Therefore, in the second step S205, the value of the average signal level Aave is calculated based on the audio signal corresponding to the time ΔT to the time T + ΔT.

On the other hand, in step S207, the average signal level
When the value of Aave is determined to be higher than the threshold value M _2, step S
In step 217, the switching flag is set to the off state (the switching flag is set to the off state even in the off state), and step S is performed.
At 215, an audio signal (unit signal) corresponding to the time ΔT is obtained, and the process returns to step S205 to calculate the average signal level of the audio signal again.

As described above, in the "switching determination routine" of the fourth embodiment, the audio signal output from the microphone 30 is constantly monitored, and the average signal level Aave is calculated from the audio signal corresponding to the time interval T. The output switching of the audio signal processing circuit 32 is determined according to the average signal level, and the attenuation factor k (coefficient k) of the amplifier 68 and the cutoff frequency of the filter circuit (LPF) 72 are determined according to the average signal level Aave value. Determine the value of (fc).

In the processing of the main routine shown in FIGS. 10 and 11, it is determined in step S173 in FIG. 11 whether or not the switching flag is on. When the switching flag is on, the microcomputer 56 proceeds to step S1.
At 75, a control signal is supplied to the amplifier 68 to set the attenuation factor to be the coefficient k times determined in the "switching determination routine". Further, the microcomputer 56 supplies a control signal to the filter circuit 72 in step S177, and sets the cutoff frequency to be (fc) determined in the “switching determination routine”.

When the setting of the attenuation factor of the amplifier 68 and the setting of the cutoff frequency of the filter circuit 72 are completed, the microcomputer 56 supplies a switch control signal to the switch 70 in step S179, and changes the output of the audio signal processing circuit 32 to a correction signal. Switch to

When the thread control is turned off in step S187 and the seek operation (thread operation) is completed, the microcomputer 56 supplies a control signal to the switch 70 in step S189 to change the output of the audio signal processing circuit 32 to a normal signal. Switch.

As described above, in the fourth embodiment, the average signal level Aave of the audio signal obtained from the microphone 30 is calculated, and the state of the switching flag and the value of the attenuation rate k (coefficient k) of the amplifier 68 are calculated according to the calculation result. And filter circuit (LPF) 72
Are determined respectively. When the seek operation is performed, the switch flag is referred to. When the state of the switch flag indicates that the output of the audio signal processing circuit 32 is switched, the value of the attenuation factor (coefficient k) of the amplifier 68 and the filter circuit (LPF) 72 are switched. Change the value.

Therefore, according to the digital camera 10 of the fourth embodiment, only when the signal level of the audio signal decreases and the influence of the seek noise increases, the audio signal processing circuit 3
Not only is it possible to prevent the information contained in the audio signal from being unnecessarily deleted by switching the audio signal output from 2 to the correction signal, but also to generate a more appropriate correction signal.

Although the above-described audio signal processing circuit 32 in the fourth embodiment includes both the amplifier 68 and the filter circuit 72, the audio signal processing circuit 32
The microcomputer 56 may control either the attenuation factor of the amplifier 68 or the cut-off frequency of the filter circuit 72. Further, the filter circuit 72 may be constituted by either a low-pass filter or a band rejection filter.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an example of an internal configuration of the audio signal processing circuit in FIG. 1;

FIG. 3 is a block diagram showing another example of the internal configuration of the audio signal processing circuit in FIG. 1;

FIG. 4 is a diagram illustrating a microcomputer according to the first and second embodiments illustrated in FIG. 1;
It is a flowchart which shows a part of process in.

FIG. 5 is a diagram illustrating a first embodiment and a second embodiment of the microcomputer illustrated in FIG. 1;
FIG. 9 is a flowchart showing another portion of the processing in FIG.

FIG. 6 is a flowchart showing a part of a process in a third embodiment of the microcomputer shown in FIG. 1;

FIG. 7 is a flowchart showing another portion of the processing in the microcomputer 3 shown in FIG. 1 according to the third embodiment.

FIG. 8 is a flowchart showing another portion of the processing in Embodiment 3 of the microcomputer shown in FIG. 1;

FIG. 9 is a flowchart showing another portion of the processing in the third embodiment of the microcomputer shown in FIG. 1;

FIG. 10 is a flowchart showing a part of a process in a fourth embodiment of the microcomputer shown in FIG. 1;

FIG. 11 is a flowchart showing another portion of the process in the fourth embodiment of the microcomputer shown in FIG. 1;

12 is a flowchart showing another portion of the process in the fourth embodiment of the microcomputer shown in FIG. 1. FIG.

FIG. 13 is an illustrative view showing one example of a free area table of the magneto-optical disk;

FIG. 14 is an illustrative view showing one example of a method of switching an output of the audio signal processing circuit;

FIG. 15 is an illustrative view showing one example of a method of determining an amplification factor of an amplifier and a cutoff frequency of a filter circuit;

FIG. 16 is an illustrative view showing one example of empty areas discretely distributed on a magneto-optical disk;

FIG. 17 is an illustrative view showing a relationship between a laser beam applied to the magneto-optical disk and a photodetector (light receiving element) for detecting the reflected light;

FIG. 18 is an illustrative view showing a spot formed on a light receiving element by a main beam in an ideal state;

FIG. 19 is an illustrative view showing a spot formed on a light receiving element by a main beam during a seek operation in the embodiment of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Digital camera 14 ... CCD imager 22 ... Buffer memory 26 ... System controller 28a ... Mode switching button 28b ... Shutter button 30 ... Microphone 32 Audio signal processing circuit 56 ... Microcomputer 58 ... Dynamic random access memory (DRAM) 66 ... Signal processing circuit 68: Amplifier 70: Switch 72: Filter circuit (LPF / BEF)

Claims (8)

[Claims] An audio recording apparatus for recording an audio signal by an optical pickup in a plurality of free areas discretely formed on a disk recording medium, a microphone for continuously receiving the audio signal from the outside, Writing means for temporarily writing the audio signal to the buffer, and moving means for moving the optical pickup to record the audio signal stored in the buffer in each of the empty areas, wherein the writing means is An audio recording apparatus comprising: an attenuating means for attenuating the audio signal when the optical pickup is moved by a moving means. 2. The apparatus according to claim 1, further comprising a determination unit configured to determine a level of the audio signal captured by the microphone, wherein the attenuation unit attenuates the audio signal according to a determination result of the determination unit. Audio recording device. 3. The attenuating means includes at least one of a first attenuating means for attenuating the audio signal regardless of frequency and a second attenuating means for attenuating the audio signal in a predetermined frequency band. 3. The audio recording device according to 2. 4. The audio recording apparatus according to claim 3, wherein said predetermined frequency band includes a frequency band of noise caused by movement of said optical pickup. 5. The audio recording apparatus according to claim 3, wherein an attenuation rate of said first attenuation means differs according to a level of said audio signal. 6. The audio recording apparatus according to claim 3, wherein a frequency band attenuated by said second attenuating means differs according to a level of said audio signal. 7. A comparing means for comparing the level of the audio signal with a first threshold value at predetermined time intervals, and measures a level reduction time during which the level of the audio signal continuously falls below the first threshold value. 7. The audio recording apparatus according to claim 2, further comprising a measuring unit configured to attenuate the audio signal when the level decrease time exceeds a second threshold. 8. The apparatus according to claim 1, wherein said determining means repeatedly calculates an average level of said audio signal for a predetermined period, and said attenuating means attenuates said audio signal when said average level falls below a third threshold value. 7. The audio recording device according to any one of 2 to 6.