JP2005117486A - Signal processor, recording device, signal processing method, program, and memory medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize widening characteristics of stereo sound by enabling compensate for the difference in sensitivities, even when there is a difference in sensitivity between two voice collecting means, or a change in the sensitivity caused by time passage and the like. <P>SOLUTION: The recording device includes a first amplifier 3, a second amplifier 4, a first LPF 5, a second LPF 6, a first mixer 7, a second mixer 8, a difference detector 9, an LPF 10, and a control circuit 11. An input signal from each microphone is amplified by the first amplifier 3 and the second amplifier 4, and the difference in output level between the first amplifier 3 and the second amplifier 4 is detected by the difference detector 9. The output signal from the difference detector 9 is integrated and detected by the LPF 10, and the difference voltage is converted into DC, to form a DC voltage. The DC voltage is applied to the control terminal of the second amplifier 4 by the control circuit 11, and the second amplifier 4 is so controlled that the output voltage of the LPF 10 becomes a reference voltage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a signal processing device, a recording device, a signal processing method, a program, and a storage medium that can correct a sensitivity difference between at least two sound collection means.

  Conventionally, as a method of performing stereo recording using a microphone, there is a method of recording sound by arranging two unidirectional microphones at a certain angle. However, the unidirectional microphone has a problem that it is not suitable for miniaturization because it needs to take a wide space around the microphone. Therefore, the idea of stereo recording using two omnidirectional microphones was devised. However, if the unidirectional microphone connected to the microphone amplifier is simply replaced with an omnidirectional microphone as it is, it does not become stereo sound, but matrix processing in the recording apparatus as shown in FIG. Signal processing based on a configuration in which the connection relationship between the amplifier and the two low-pass filters is crossed.

  FIG. 8 is a block diagram illustrating a configuration example of a recording apparatus according to a conventional example.

  In FIG. 8, the first amplifier (AMP1) 43 amplifies the signal input from the input terminal 41 to which the left channel omnidirectional microphone is connected. The second amplifier (AMP2) 44 amplifies the signal input from the input terminal 42 to which the right channel omnidirectional microphone is connected. The first low-pass filter (LPF1) 45 receives the output signal of the second amplifier 44 and delays the phase. The second low-pass filter (LPF2) 46 receives the output signal of the first amplifier 43 and delays the phase.

  The first mixer (MIX1) 47 subtracts the output signal of the first low-pass filter 45 from the output signal of the first amplifier 43. The second mixer (MIX2) 48 subtracts the output signal of the second low-pass filter 46 from the output signal of the second amplifier 44. The output signal of the first mixer 47 becomes the left channel signal, and the output signal of the second mixer 48 becomes the right channel signal.

Now, the stereo feeling of the sound created in the recording apparatus as shown in FIG. 8 can be shown by a polar pattern obtained by computer simulation. As an example of polar pattern characteristics by the recording apparatus shown in FIG. 8, the arrangement interval of two omnidirectional microphones is 15 mm, and the time constants of the first low-pass filter 45 and the second low-pass filter 46 are 4.9e ^−5. FIG. 9 shows the characteristics when the frequency of the input signal of the omnidirectional microphone is 1 kHz under the condition that the difference in sensitivity between the two omnidirectional microphones is zero.

On the other hand, as another conventional technique, a technique related to sensitivity correction of a stereo microphone has been proposed (for example, see Patent Document 1).
JP 2000-224688 A

In the stereo processing by the recording apparatus as described above, the sensitivity of the omnidirectional microphone is an important parameter that gives the sound spread. FIG. 9 shows the polar pattern characteristics when the sensitivity difference between the two omnidirectional microphones is zero. FIG. 10 shows the polar pattern characteristics when the sensitivity difference between the two omnidirectional microphones is 2 dB. FIG. 10 shows the measurement under the same conditions as in FIG. 9 (non-directional microphone arrangement interval 15 mm, time constant 4.9 e ⁻⁵ sec, frequency 1 kHz).

  However, in the prior art, as can be seen from FIG. 9 and FIG. 10, if there is a difference in sensitivity between two omnidirectional microphones, the polar pattern is destroyed (FIG. 10), and the intended polar pattern characteristics (FIG. 10) There was a problem that 9) could not be obtained. Therefore, in order to correct the sensitivity difference between the two omnidirectional microphones, it is necessary to select the sensitivity of the omnidirectional microphone and make adjustments in the manufacturing process. In addition, when the sensitivity of the omnidirectional microphone is changed due to secular change, the polar pattern characteristic remains in the shifted sensitivity, and the initial characteristic cannot be secured.

  The object of the present invention is to make it possible to correct the difference in sensitivity even when there is a difference in sensitivity between the two sound collection means or when the sensitivity changes with aging, etc., and to stabilize the spread characteristics of stereo sound. A signal processing apparatus, a recording apparatus, a signal processing method, a program, and a storage medium.

  In order to achieve the above object, the present invention is a signal processing apparatus provided with an amplifying means that is provided corresponding to each of at least two sound collecting means and amplifies the input signal of the corresponding sound collecting means, And a detection unit that detects a difference between output signals of the amplification units, and a control unit that controls the output of the detection unit by controlling an amplification factor of any one of the amplification units. To do.

  Further, the present invention includes an integrating unit that integrates the output signal of the detecting unit, and a detecting unit that detects the output signal of the integrating unit, and any one of the amplifying units can change the amplification factor. And the control means controls the amplification factor by applying the output signal of the detection means to the side of the amplification means that can change the amplification factor.

  In the invention, it is preferable that the control unit controls the amplification factor of any one of the amplification units so as to reduce the output of the detection unit.

  Further, the present invention is a signal processing device provided corresponding to each of at least two sound collecting means and provided with an amplifying means for amplifying an input signal of the corresponding sound collecting means, each corresponding to each of the amplifying means. A conversion means for converting the output signal of the corresponding amplification means into a digital signal, a detection means for detecting a difference between the output signals of the respective conversion means, and controlling each of the conversion means And control means for controlling the output of the detection means.

  In addition, the present invention includes an integration unit that integrates the output signal of the detection unit, and the control unit adds the output signal of the integration unit to one of the output signals of each of the conversion units, or Subtracted from the output signal of any one of the conversion means.

  Further, the present invention is characterized in that the control means controls so as to reduce the output of the detection means by controlling any one of the conversion means.

  Further, the present invention provides a first amplifying means for amplifying the input signal of the first sound collecting means, and a second amplifying means for amplifying the input signal of the second sound collecting means, the gain of which is variable. Detecting means for detecting a difference between output signals of the first and second amplifying means, integrating means for integrating the output signal of the detecting means, and detecting means for detecting the output signal of the integrating means, And a control means for controlling the gain of the detection means to be reduced by applying the output signal of the detection means to the second amplification means and controlling the amplification factor.

  The present invention further includes a first amplifying means for amplifying an input signal of the first sound collecting means, a second amplifying means for amplifying the input signal of the second sound collecting means, and the first amplifying means. Each of the first conversion means for converting the output signal of the second conversion means into a digital signal, the second conversion means for converting the output signal of the second amplification means into a digital signal, and the first and second conversion means Detection means for detecting the difference between the output signals; integration means for integrating the output signal of the detection means; and output signal of the integration means for either one of the first conversion means or the second conversion means Control means for controlling the output of the detection means to be reduced by adding to the output signal or by subtracting from the output signal of either the first conversion means or the second conversion means It is good also as a structure.

  According to the present invention, the output of the detecting means for detecting the difference between the output signals of the respective amplifying means is controlled by controlling the amplification factor of any one of the amplifying means for amplifying the input signals of the respective sound collecting means. Therefore, even when there is a difference in sensitivity between the sound collecting means, the sensitivity difference can be corrected in the process of taking the input signal (sound) from each sound collecting means. As a result, the spread characteristic of stereo sound is stabilized and the original target characteristic can be realized. Further, even when the sensitivity changes with the aging of the sound collecting means, the sensitivity change can be corrected, and the stereo sound field can be maintained in the best state.

  The present invention also provides an amplification factor by applying the output signal of the detection means for detecting the output signal obtained by integrating the output signal of the detection means to the side of the amplification means where the amplification factor can be changed. Therefore, the output of the detection means for detecting the difference between the output signals of the amplification means can be controlled. Sensitivity difference can be corrected in the process of capturing.

  In addition, since the present invention controls the amplification factor of any one of the amplifying means so as to reduce the output of the detecting means, even if there is a difference in sensitivity between the sound collecting means as described above. The sensitivity difference can be corrected in the process of taking the input signal from each voice collecting means.

  Further, the present invention controls the difference between the output signals of the conversion means by controlling any one of the conversion means for converting the output signals of the amplification means for amplifying the input signals of the sound collection means into digital signals. Since the output of the detecting means for detecting the sound is controlled, the sensitivity difference can be corrected in the process of taking the input signal (sound) from each sound collecting means even when each sound collecting means has a sensitivity difference. As a result, the spread characteristic of stereo sound is stabilized and the original target characteristic can be realized. Further, even when the sensitivity changes with the aging of the sound collecting means, the sensitivity change can be corrected, and the stereo sound field can be maintained in the best state.

  In the present invention, the output signal of the integrating means for integrating the output signal of the detecting means is added to the output signal of any one of the conversion means or subtracted from the output signal of any one of the conversion means. The output of the detecting means for detecting the difference in the output signal of the converting means can be controlled. Similarly to the above, even if there is a sensitivity difference in each sound collecting means, the sensitivity difference in the process of taking the input signal from each sound collecting means Can be corrected.

  In addition, since the present invention controls so that the output of the detecting means is reduced by controlling any one of the converting means, as described above, even if there is a difference in sensitivity between the sound collecting means, The sensitivity difference can be corrected in the process of taking the input signal from the collecting means.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration example of a recording apparatus according to the first embodiment of the present invention.

  In FIG. 1, the recording apparatus employs a system in which two omnidirectional microphones (sound collecting means) (not shown) are arranged in the vicinity to perform stereo processing on the sound, and the first input terminal 1, Second input terminal 2, first amplifier 3 (amplifying means), second amplifier 4 (amplifying means), first low-pass filter 5, second low-pass filter 6, first mixer 7, second , A difference detector 9 (detection means), a low-pass filter 10 (integration means), and a control circuit 11 (detection means, control means).

  The first input terminal 1 is a terminal that takes in an input signal from the omnidirectional microphone of the left channel. The second input terminal 2 is a terminal for capturing an input signal from the omnidirectional microphone of the right channel. The first amplifier 3 amplifies an input signal to the first input terminal 1. The second amplifier 4 amplifies an input signal to the second input terminal 2 and is configured as a variable amplifier whose amplification factor can be changed by applying a voltage to a control terminal (not shown) provided in the second amplifier 4. Has been. The first LPF 5 delays the phase of the output signal of the second amplifier 4. The second LPF 6 delays the phase of the output signal of the first amplifier 3.

  The first mixer 7 subtracts the output signal of the first LPF 5 from the output signal of the first amplifier 3. The second mixer 8 subtracts the output signal of the second LPF 6 from the output signal of the second amplifier 4. The difference detector 9 detects the difference between the output signal of the first amplifier 3 and the output signal of the second amplifier 4. The LPF 10 integrates the output signal of the difference detector 9. The control circuit 11 generates the output signal of the LPF 10 in a form suitable for controlling the amplification factor of the second amplifier 4 (detects the output signal of the LPF 10 and uses it as a DC voltage), and converts the DC voltage into the second amplifier. 4 is applied to the control terminal 4 to set the amplification factor.

  This embodiment is different from the conventional example (FIG. 8) in that the second amplifier 4 is a variable amplifier whose gain can be changed by control from the outside (control circuit 11), and further the first amplifier 3 A difference detector 9 for detecting the difference between the output signal of the second amplifier 4 and the output signal of the second amplifier 4, an LPF 10 for integrating the output signal of the difference detector 9, and a control circuit for controlling the amplification factor of the second amplifier 4 11 is provided.

  Next, the operation of the recording apparatus of the present embodiment having the above configuration will be described in detail with reference to FIGS.

  FIG. 2 is a diagram illustrating output signals of the first amplifier 3 and the second amplifier 4. FIG. 3 is a diagram showing signals corresponding to the difference between the output signals of the first amplifier 3 and the second amplifier 4. FIG. 4 is a diagram illustrating a voltage obtained by integrating and detecting a signal corresponding to the difference between the output signals of the first amplifier 3 and the second amplifier 4 and converting it to DC. FIG. 5 is a schematic flowchart showing the operation of the recording apparatus.

  In the above configuration, first, in the first input terminal 1 and the second input terminal 2, the input signals to these input terminals are input signals from two omnidirectional microphones arranged in the vicinity. Almost no phase difference occurs. Particularly in the low sound range, signals having substantially the same phase are input to the first input terminal 1 and the second input terminal 2.

For example, if the interval between two omnidirectional microphones is 15 mm, the phase difference when the frequency of the input signal of the omnidirectional microphone is 100 Hz is that the sound speed is 340 m / sec.
Phase difference (deg) = 360 * 15 * 100/340000 = 1.6 (deg)
Thus, even when the frequency of the input signal of the omnidirectional microphone is 1 kHz, the phase difference is about 16 deg.

  Input signals from the left and right channel omnidirectional microphones for the first input terminal 1 and the second input terminal 2 are amplified by the first amplifier 3 and the second amplifier 4, respectively (step S1). At this time, the amplification factor of the second amplifier 4 is determined (set) by applying a voltage from the control circuit 11 to the control terminal of the second amplifier 4. Since the control in the portion including the second amplifier 4, the difference detector 9, the LPF 10, and the control circuit 11 is a loop control, the control from the control circuit 11 to the second amplifier 4 is divided in the first half for convenience of explanation. The state in which the control is performed will be described in the second half.

  The output signal from the first amplifier 3 is input to the second LPF 6 and the phase thereof is delayed, and the output signal of the second LPF 6 is subtracted from the output signal of the second amplifier 4 by the second mixer 8. As a result, a right channel signal is generated. The output signal from the second amplifier 4 is input to the first LPF 5 and the phase is delayed, and the output signal of the first LPF 5 is subtracted from the output signal of the first amplifier 3 by the first mixer 7. As a result, a left channel signal is generated.

  In the above conventional example, when the sensitivity difference between the omnidirectional microphones connected to the first input terminal and the second input terminal is zero, the polar pattern characteristic that is originally aimed for is obtained, and the sensitivity of the omnidirectional microphone is obtained. It has been described that the polar pattern characteristics are lost when the difference is 2 dB.

  In this embodiment, when an omnidirectional microphone having a sensitivity difference of 2 dB, for example, is connected to the first input terminal 1 and the second input terminal 2 (the sensitivity of the omnidirectional microphone of the left channel is that of the right channel). For example, the case of 2 dB higher than the omnidirectional microphone will be described more specifically.

  It is assumed that the amplification factor of the second amplifier 4 is the same value as the amplification factor of the first amplifier 3. In this case, when the output signal of the first amplifier 3 and the output signal of the second amplifier 4 are compared, the output signal of the first amplifier 3 is the output of the second amplifier 4 due to the sensitivity difference of the omnidirectional microphone. 2 dB higher than the output signal. FIG. 2 shows output signals of the first amplifier 3 and the second amplifier 4. In FIG. 2, the solid line indicates the output signal of the first amplifier 3, and the broken line indicates the output signal of the second amplifier 4.

  Next, the differential detector 9 detects a differential voltage that is a level difference between the output signal of the first amplifier 3 and the output signal of the second amplifier 4 (step S2). The operation of detecting the output level difference is an operation of subtracting the output signal of the second amplifier 4 from the output signal of the first amplifier 3. FIG. 3 shows a signal corresponding to the difference between the output signals of the first amplifier 3 and the second amplifier 4.

  Next, the output signal (difference voltage) of the difference detector 9 is integrated by the LPF 10 to remove a high frequency component, and the integrated difference voltage is detected by the control circuit 11 and converted into a DC voltage (step). S3). FIG. 4 shows a voltage obtained by integrating and detecting a signal corresponding to the difference between the output signals of the first amplifier 3 and the second amplifier 4 and converting it to DC.

  Next, the control circuit 11 applies the DC voltage to the control terminal of the second amplifier 4 so that the output voltage of the LPF 10 becomes the reference voltage (in other words, the output of the difference detector 9 becomes zero). The second amplifier 4 is controlled (step S4). As a result, the difference between the input voltages from the first amplifier 3 and the second amplifier 4 with respect to the difference detector 9 is eliminated, and the output levels of the first amplifier 3 and the second amplifier 4 become the same.

  In summary, the signals input to the left channel and right channel omnidirectional microphones are amplified by the first amplifier 3 and the second amplifier 4, respectively. A difference detector 9 detects a difference between the output signals of the amplifier 4. The signal detected by the difference detector 9 is integrated by the LPF 10 to remove a high frequency component and take out an average amplitude difference. The integrated value is fed back to the second amplifier 4 so that the output of the difference detector 9 is controlled to zero. As a result, an operation for correcting the sensitivity difference between the left and right omnidirectional microphones can be realized.

  As described above, according to the present embodiment, even when there is a sensitivity difference between the left and right channel omnidirectional microphones, the sensitivity difference is corrected in the process of capturing sound from the left and right omnidirectional microphones. Can do. As a result, the spread characteristic of stereo sound is stabilized, and the polar pattern characteristic that is originally intended can be realized. Further, even when the sensitivity changes with the aging of the omnidirectional microphone, the sensitivity change can be corrected, and the stereo sound field can be maintained in the best state.

[Second Embodiment]
FIG. 6 is a block diagram showing a configuration example of a recording apparatus according to the second embodiment of the present invention.

  In FIG. 6, the recording apparatus employs a system in which two omnidirectional microphones (sound collecting means) (not shown) are arranged in the vicinity to perform stereo processing on the sound, and the first input terminal 21, Second input terminal 22, first amplifier 23 (amplification means), second amplifier 24 (amplification means), first A / D converter 25 (conversion means), second A / D converter 26 (conversion) Means), first digital low-pass filter 27, second digital low-pass filter 28, first mixer 29, second mixer 30, difference detector 31 (detection means), digital low-pass filter 32 (integration means). A correction control circuit 33 (control means) is provided.

  The first input terminal 21 is a terminal that takes in an input signal from a left-channel omnidirectional microphone. The second input terminal 22 is a terminal for capturing an input signal from the omnidirectional microphone of the right channel. The first amplifier 23 amplifies an input signal to the first input terminal 21. The second amplifier 24 amplifies the input signal to the second input terminal 22. The first A / D converter 25 converts the output signal (analog signal) of the first amplifier 23 into a digital signal. The second A / D converter 26 converts the output signal (analog signal) of the second amplifier 24 into a digital signal. The first digital LPF 27 delays the phase of the output signal of the second A / D converter 26. The second digital LPF 28 delays the phase of the output signal of the first A / D converter 25.

  The first mixer 29 subtracts the output signal of the first digital LPF 27 from the output signal of the first A / D converter 25. The second mixer 30 subtracts the output signal of the second digital LPF 28 from the output signal of the second A / D converter 26. The difference detector 31 detects the difference between the output signal of the first A / D converter 25 and the output signal of the second A / D converter 26. The digital LPF 32 integrates the output signal of the difference detector 31. The correction control circuit 33 adds the value corresponding to the sensitivity difference to the output value of the second A / D converter 26 so that the difference data described later becomes zero, thereby outputting the output of the second A / D converter 26. Correct the value.

  Next, the operation of the recording apparatus of the present embodiment having the above configuration will be described in detail with reference to FIGS.

  FIG. 7 is a schematic flowchart showing the operation of the recording apparatus.

  In the above configuration, first, there is almost no phase difference between the first input terminal 21 and the second input terminal 22 as described in the first embodiment. Particularly in the low sound range, signals having substantially the same phase are input to the first input terminal 21 and the second input terminal 22.

  Input signals from the left and right channel omnidirectional microphones for the first input terminal 21 and the second input terminal 22 are amplified by the first amplifier 23 and the second amplifier 24, respectively (step S11). Now, for convenience of explanation, a description will be given in a state where the correction operation for the output value of the second A / D converter 26 from the correction control circuit 33 is prohibited in the first half, and a state in which the correction operation is performed in the second half.

  The output signal from the first amplifier 23 is input to the first A / D converter 25 to be converted into digital data, and the output signal from the second amplifier 24 is converted to the second A / D converter 26. Is converted into digital data (step S12).

  The phase of the output data of the first A / D converter 25 is delayed by being input to the second digital LPF 28, and the output data of the second A / D converter 26 is input to the first digital LPF 27. This delays the phase. The first mixer 29 subtracts the output data of the first digital LPF 27 from the output data of the first A / D converter 25 to generate left channel data. The second mixer 30 subtracts the output data of the second digital LPF 28 from the output data of the second A / D converter 26, thereby generating right channel data.

  In the above conventional example, when the sensitivity difference between the omnidirectional microphones connected to the first input terminal and the second input terminal is zero, the polar pattern characteristic that is originally aimed for is obtained, and the sensitivity of the omnidirectional microphone is obtained. It has been described that the polar pattern characteristics are lost when the difference is 2 dB.

  In this embodiment, when an omnidirectional microphone having a sensitivity difference of 2 dB, for example, is connected to the first input terminal 21 and the second input terminal 22 (the sensitivity of the omnidirectional microphone of the left channel is that of the right channel). For example, the case of 2 dB higher than the omnidirectional microphone will be described more specifically.

  It is assumed that the amplification factor of the second amplifier 24 is the same value as the amplification factor of the first amplifier 23. In this case, when the output signal of the first amplifier 23 and the output signal of the second amplifier 24 are compared, the output signal of the first amplifier 23 is the output of the second amplifier 24 due to the sensitivity difference of the omnidirectional microphone. 2 dB higher than the output signal. Therefore, the output data of the first A / D converter 25 is 2 dB higher than the output data of the second A / D converter 26.

  Next, the difference detector 31 detects the difference between the output data of the first A / D converter 25 and the output data of the second A / D converter 26 (step S13). Next, the output signal of the difference detector 31 is integrated by the digital LPF 32, and average difference data is calculated by the correction control circuit 33 (step S14).

  Next, a value of +2 dB corresponding to the sensitivity difference of the omnidirectional microphone is added to the output value of the second A / D converter 26 so that the difference data becomes zero by the correction control circuit 33 (step S15). ). As a result, there is no difference in input data from the first A / D converter 25 and the second A / D converter 26 to the difference detector 31, and the output data of the first A / D converter 25 and the second A / D converter 26 are eliminated. The output data of the / D converter 26 is the same.

  In the above description, the sensitivity of the left channel omnidirectional microphone is 2 dB higher than that of the right channel omnidirectional microphone. However, the sensitivity of the left channel omnidirectional microphone is higher than that of the right channel omnidirectional microphone. For example, when the value is 2 dB lower, the control is performed to reduce the value of 2 dB corresponding to the sensitivity difference of the omnidirectional microphone from the output value of the second A / D converter 26.

  As described above, according to the present embodiment, even when there is a sensitivity difference between the left and right channel omnidirectional microphones, the sensitivity difference is corrected in the process of capturing sound from the left and right omnidirectional microphones. Can do. As a result, the spread characteristic of stereo sound is stabilized, and the polar pattern characteristic which is originally aimed can be realized. Further, even when the sensitivity changes with the aging of the omnidirectional microphone, the sensitivity change can be corrected, and the stereo sound field can be maintained in the best state.

[Other embodiments]
In the first embodiment, the control is performed so that the output voltage of the LPF 10 becomes the reference voltage (the output of the difference detector 9 becomes zero), but the output of the difference detector 9 is completely zero. The object of the present invention can be achieved by controlling so as to approach zero.

  In the second embodiment, the control is performed so that the difference data based on the difference detection of the difference detector 31 becomes zero. However, the difference data is controlled so as to approach zero even if the difference data is not completely zero. Thus, the object of the present invention can be achieved.

  In the first and second embodiments, the control in the case where the sensitivity of the omnidirectional microphone of the left channel is higher than that of the omnidirectional microphone of the right channel has been described as an example. It is also possible to apply to the control when is higher than the left channel omnidirectional microphone.

  In the first embodiment, the case where the gain of the first amplifier 3 is fixed and the gain of the second amplifier 4 can be changed is taken as an example. The present invention can also be applied to a case where the amplification factor of the first amplifier 3 is fixed and variable.

  In the second embodiment, the control for correcting the output value of the second A / D converter 26 is described as an example. However, the control is also applied to the control for correcting the output value of the first A / D converter 25. It is possible.

  In the second embodiment, correction for adding a value corresponding to the sensitivity difference of the omnidirectional microphone to the output value of the second A / D converter 26 is described as an example. However, the first A / D converter It is also possible to perform correction by subtracting a value corresponding to the sensitivity difference of the omnidirectional microphone from the 25 output values.

  In the first and second embodiments, the case where the signal processing device of the present invention is applied to a recording device with a microphone that records audio is taken as an example, but recording with a microphone that performs recording and reproduction of audio is described. It can also be applied to a playback device. Specific examples include a video camera, a voice recorder, a radio cassette recorder, and the like, but the present invention is not limited to application to a specific apparatus.

  The present invention supplies a software program (flowcharts in FIGS. 5 and 7) that realizes the functions of the above-described embodiments to a computer or CPU, and the computer or CPU reads and executes the supplied program. Can be achieved.

  In this case, the program is directly supplied from a storage medium storing the program, or downloaded from another computer or database (not shown) connected to the Internet, a commercial network, a local area network, or the like. Supplied.

  The form of the program may be in the form of object code, program code executed by an interpreter, script data supplied to an OS (operating system), and the like.

  The present invention also supplies a computer or CPU with a storage medium storing a software program that implements the functions of the above-described embodiments, and the computer or CPU reads and executes the program stored in the storage medium. Can also be achieved.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

  As a storage medium for storing the program code, for example, ROM, RAM, NV-RAM, floppy (registered trademark) disk, hard disk, optical disk (registered trademark), magneto-optical disk, CD-ROM, MO, CD-R, CD -RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, etc.

  The function of the above-described embodiment is not only by executing the program code read from the computer, but the OS or the like running on the computer performs part or all of the actual processing based on the instruction of the program code. Can also be realized.

1 is a block diagram illustrating a configuration example of a recording apparatus according to a first embodiment of the present invention. It is a figure which shows each output signal of a 1st amplifier and a 2nd amplifier. It is a figure which shows the signal corresponded to the difference of each output signal of a 1st amplifier and a 2nd amplifier. It is a figure which shows the voltage which integrated and detected the signal equivalent to the difference of each output signal of a 1st amplifier and a 2nd amplifier, and was converted into DC. 3 is a schematic flowchart showing the operation of the recording apparatus. It is a block diagram which shows the structural example of the recording device which concerns on the 2nd Embodiment of this invention. 3 is a schematic flowchart showing the operation of the recording apparatus. It is a block diagram which shows the structural example of the recording device which concerns on a prior art example. It is a figure which shows the polar pattern characteristic in case the sensitivity difference of two omnidirectional microphones is zero. It is a figure which shows a polar pattern characteristic in case the sensitivity difference of two omnidirectional microphones is 1 dB.

Explanation of symbols

3 First amplifier 4 Second amplifier 5 First LPF
6 Second LPF
7 First mixer 8 Second mixer 9 Differential detector 10 LPF
DESCRIPTION OF SYMBOLS 11 Control circuit 23 1st amplifier 24 2nd amplifier 25 1st A / D converter 26 2nd A / D converter 27 1st digital LPF
28 Second digital LPF
29 First mixer 30 Second mixer 31 Differential detector 32 Digital LPF
33 Correction control circuit

Claims (12)

A signal processing apparatus provided with corresponding to each of at least two voice collecting means, and having an amplifying means for amplifying an input signal of the corresponding voice collecting means,
And a detection unit that detects a difference between output signals of the amplification units, and a control unit that controls the output of the detection unit by controlling an amplification factor of any one of the amplification units. Signal processing device. Integrating means for integrating the output signal of the detecting means; and detecting means for detecting the output signal of the integrating means;
Any one of the amplifying means is configured to change the amplification factor,
2. The signal processing apparatus according to claim 1, wherein the control unit controls the amplification factor by applying the output signal of the detection unit to a side of the amplification unit where the amplification factor can be changed. .   The signal processing apparatus according to claim 1, wherein the control unit controls the output of the detection unit to be small. A signal processing apparatus provided with corresponding to each of at least two voice collecting means, and having an amplifying means for amplifying an input signal of the corresponding voice collecting means,
A conversion unit that is provided corresponding to each of the amplification units and that converts an output signal of the corresponding amplification unit into a digital signal; a detection unit that detects a difference between output signals of the conversion units; and A signal processing apparatus comprising: control means for controlling the output of the detection means by controlling either one of them. Integrating means for integrating the output signal of the detecting means;
5. The control unit according to claim 4, wherein the output signal of the integration unit is added to one of the output signals of each of the conversion units or subtracted from the output signal of one of the conversion units. Signal processing equipment.   The signal processing apparatus according to claim 4, wherein the control unit controls the output of the detection unit to be small.   A recording apparatus comprising the signal processing apparatus according to any one of claims 1 to 6 and recording audio. A signal processing method of a signal processing device provided with corresponding to each of at least two voice collecting means and having an amplifying means for amplifying an input signal of the corresponding voice collecting means,
A signal processing method comprising: controlling an output of a detection unit that detects a difference between output signals of the amplification units by controlling an amplification factor of any one of the amplification units. A signal processing method of a signal processing device provided with corresponding to each of at least two voice collecting means and having an amplifying means for amplifying an input signal of the corresponding voice collecting means,
Detection for detecting the difference between the output signals of the respective conversion means by controlling any one of the conversion means provided corresponding to each of the amplification means and converting the output signal of the corresponding amplification means into a digital signal. A signal processing method characterized by controlling the output of the means. A program for causing a computer to execute a signal processing method of a signal processing apparatus that is provided corresponding to each of at least two voice collecting means and includes an amplifying means for amplifying an input signal of the corresponding voice collecting means,
A program comprising a module for controlling an output of a detecting means for detecting a difference between output signals of the respective amplifying means by controlling an amplification factor of any one of the amplifying means. A program for causing a computer to execute a signal processing method of a signal processing apparatus that is provided corresponding to each of at least two voice collecting means and includes an amplifying means for amplifying an input signal of the corresponding voice collecting means,
Detection for detecting the difference between the output signals of the respective conversion means by controlling any one of the conversion means provided corresponding to each of the amplification means and converting the output signal of the corresponding amplification means into a digital signal. A program comprising a module for controlling the output of the means.   A computer-readable storage medium storing the program according to claim 10 or 11.

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