JP2011151698A - Source signal supplementation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supplement a predetermined frequency band in a source signal without depending on the signal level of the source signal outputted from a sound source and specifically to reproduce a sound effect of low-band sound lower than the reproduction capability of a loudspeaker in a range reproducible by the loudspeaker. <P>SOLUTION: A source signal supplementation apparatus includes: a pulse generating means 41 for generating a signal consisting of an impulse train with a predetermined frequency interval; a first filter 43 that adjusts the signal level of the impulse train of the signal generated by the pulse generating means 41 in compliance with the frequency band and generates a multicarrier signal I2; and a first multiplication means for generating a first supplementation signal by multiplying the source signal outputted from the sound source by the multicarrier signal I2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sound source signal complementing device, and more particularly to a sound source signal complementing device capable of performing a complementing process in a predetermined frequency band on a sound source signal output from a sound source unit.

  In general, a frequency band that can be reproduced by a speaker is often narrower than a frequency band of a signal output from a sound source (hereinafter referred to as a sound source signal). For this reason, in order to faithfully reproduce the sound source signal on the speaker, it is necessary to use a speaker having a wide reproducible frequency band as much as possible. However, since the frequency band that can be reproduced by the speaker is greatly affected by the size and structure of the speaker, it may be difficult to employ a speaker with a wide bandwidth. In particular, if the low-band sound source signal is not sufficiently reproduced by the speaker, the low-frequency sound is insufficient, and the listener may be recognized as a sound lacking in the power and spread of music.

  For this reason, as a technology for reproducing low-frequency sounds below the speaker's playback capability on the speaker, output low-frequency sounds in a frequency band that can be reproduced by the speakers by increasing the frequency characteristics by obtaining harmonics of low-frequency sounds. The method of performing is proposed (for example, refer to Patent Document 1).

  Specifically, the low frequency component of the sound source signal output from the sound source is extracted, and the harmonics are generated by squaring each band signal using a plurality of cascaded analog multipliers, It is configured to output from a speaker.

  In this way, by correcting the frequency of the low-frequency sound to a frequency band that can be reproduced by the speaker, it is possible to eliminate the low-frequency shortage of the sound output from the speaker, and to reproduce the force and spread of the sound. It is possible.

JP 2001-245399 A

  However, as described above, in the method of generating harmonics of low-frequency sounds and outputting them from the speaker, since the process of repeating the square without considering the signal level in the low frequency range of the sound source is performed, the signal level is higher than 1. If the signal level is too small, the signal level of the generated overtone is remarkably reduced. If the signal level is higher than 1, the signal level of the generated overtone is remarkably increased.

  The present invention has been made in view of the above problems, and can complement a predetermined frequency band in a sound source signal without depending on the signal level of the sound source signal output from the sound source. It is an object of the present invention to provide a sound source signal complementing device that performs complementation that can reproduce an acoustic effect in a low-frequency sound having a reproduction capacity equal to or lower than that in a sound range reproducible by a speaker.

  In order to solve the above-described problem, a sound source signal complementing apparatus according to the present invention includes a pulse generation unit that generates a signal including an impulse train having a predetermined frequency interval, and an impulse train of the signal generated by the pulse generation unit. First filter means for generating a multicarrier signal by adjusting the signal level according to the frequency band, and generating a first complementary signal by multiplying the sound source signal output from the sound source means by the multicarrier signal And a first multiplication means.

  In the sound source signal complementing apparatus according to the present invention, a signal composed of an impulse train is weighted by being adjusted in accordance with the frequency band in the first filter means to be a multicarrier signal. By multiplying, a complementary signal (first complementary signal) is generated. Since this complementary signal is generated by multiplying a sound source signal by a multicarrier signal composed of an impulse train, the signal characteristics of the sound source signal are shifted to a plurality of frequencies over a predetermined frequency band. .

  Since the complementary signal is a signal having a plurality of frequency-shifted waveforms in this way, it is possible to perform output level complementation within a predetermined frequency band with reference to the sound source signal, and a sound source in the corresponding frequency range. It is possible to effectively complement the signal.

  Further, in the sound source signal complementing device according to the present invention, the output level in a specific frequency band can be complemented using the impulse train generated by the pulse generating means, and therefore it depends on the signal level of the sound source signal. Complementary processing can be performed without any problem. Therefore, as in the case where the sound source signal is complemented by generating overtones based on the sound source signal, the signal level of the sound source signal does not affect the complementary characteristics, and the desired frequency band is further desired. Depending on the signal level, the effect can be complemented.

  Further, as described above, since the multicarrier signal is generated based on the impulse train, it is not necessary to individually generate and synthesize a plurality of waveform components having different frequencies and phases. It is possible to generate a complementary signal that is frequency-shifted in plural over the band.

  Furthermore, the above-described sound source signal complementing device includes second filter means for performing filtering processing by extracting a signal output of a predetermined frequency band for the sound source signal output from the sound source means, and the first multiplication The means may multiply the sound source signal filtered by the second filter means by the multicarrier signal. In particular, in the sound source signal complementing apparatus, the second filter means The filtering process may be performed so that a signal output of a frequency band that can be reproduced by a speaker for outputting the sound source signal is extracted.

  In the sound source signal complementing apparatus described above, the frequency band of the sound source signal to be multiplied by the multicarrier signal can be adjusted by the second filter means. For this reason, for example, when there is a band in which a sound source signal is to be positively complemented by complementary signals such as a low frequency, a mid frequency, and a high frequency, the sound source signal is filtered by the second filter means. Accordingly, it is possible to generate a complementary signal that can be effectively complemented.

  In particular, when the frequency band extracted by the second filter means is a signal output equal to or lower than the frequency band reproducible by the speaker, a plurality of frequency-shifted waveforms with reference to the frequency band extracted by the second filter means A complementary signal having an output can be generated. For this reason, even if the frequency band extracted by the second filter means is less than or equal to the frequency band that can be reproduced by the speaker, the acoustic effect in the frequency band that cannot be reproduced by the speaker is frequency-shifted by the generated complementary signal. The complementary signal can be reproduced in a frequency band that can be reproduced by the speaker.

  By reproducing the sound effect in the frequency band that cannot be reproduced by the speaker in this way in the frequency band that can be reproduced by the speaker, it is possible to eliminate the low frequency shortage of the sound output from the speaker, It becomes possible to reproduce the spread.

  The sound source signal complementing device described above is based on the first phase means for generating the sound source signal I1 of 0 degree phase and the sound source signal Q1 of 90 degree phase based on the sound source signal, and on the basis of the multicarrier signal. Second phase means for generating a 0 degree phase multicarrier signal I2 and a 90 degree phase multicarrier signal Q2 and a second complementary signal by multiplying the sound source signal Q1 by the multicarrier signal Q2 Second multiplying means, phase inverting means for inverting the phase of the second complementary signal generated by the second multiplying means, and multiplying the sound source signal I1 by the multicarrier signal I2. An addition signal for generating a complementary signal by adding a second complementary signal whose phase has been inverted by the phase inverting means to the first complementary signal generated by one multiplying means. It may be provided with a means.

  In this way, the first complementary signal generated by multiplying the 0 degree phase sound source signal I1 by the 0 degree phase multicarrier signal I2 is 90 degrees with respect to the 90 degree phase sound source signal Q1. It is possible to effectively suppress the mirror image in the generated complementary signal by adding the second complementary signal generated by multiplying the phase multi-carrier signal Q2 by inverting the phase.

  According to the sound source signal complementing apparatus of the present invention, a signal composed of an impulse train is weighted by being adjusted in accordance with the frequency band in the first filter means, and becomes a multicarrier signal. Is multiplied to generate a complementary signal (first complementary signal). Since this complementary signal is generated by multiplying the sound source signal by a multicarrier signal composed of an impulse train, the signal characteristics of the sound source signal are shifted in frequency over a predetermined frequency band.

  Since the complementary signal is a signal having a plurality of frequency-shifted waveforms in this way, it is possible to perform output level complementation within a predetermined frequency band with reference to the sound source signal, and a sound source in the corresponding frequency range. It is possible to effectively complement the signal.

  Further, in the sound source signal complementing device according to the present invention, the output level in a specific frequency band can be complemented using the impulse train generated by the pulse generating means, and therefore it depends on the signal level of the sound source signal. Complementary processing can be performed without any problem. Therefore, as in the case where the sound source signal is complemented by generating overtones based on the sound source signal, the signal level of the sound source signal does not affect the complementary characteristics, and the desired frequency band is further desired. Depending on the signal level, the effect can be complemented.

  Further, as described above, since the multicarrier signal is generated based on the impulse train, it is not necessary to individually generate and synthesize a plurality of waveform components having different frequencies and phases. It is possible to easily generate complementary signals that are frequency-shifted in a plurality of bands.

It is the block diagram which showed schematic structure of the audio complementation apparatus which concerns on this Embodiment. It is the block diagram which showed schematic structure of the frequency conversion part which concerns on this Embodiment. (A) is the block diagram which showed schematic structure of the 1st phase shifter part which concerns on this Embodiment, (b) is the block diagram which showed schematic structure of the multicarrier signal generation part. (A) is the figure which showed typically an example of the impulse train produced | generated in the pulse generation part which concerns on this Embodiment, (b) is the output spectrum of the impulse train produced | generated by the pulse generation part. It is the figure which showed an example. It is the figure which showed an example of the coefficient in the FIR filter of the Hilbert transform part which concerns on this Embodiment. (A) is the figure which showed an example of the output waveform of the sound source signal I1 and the sound source signal Q1 output in the 1st phase shifter part which concerns on this Embodiment, (b) is a 1st phase shifter part. It is the figure which showed an example of the output spectrum of the sound source signal I1 output in FIG. (A) is the figure which showed an example of the output waveform of the multicarrier signal I2 and the multicarrier signal Q2 output in the 2nd phase shifter part which concerns on this Embodiment, (b) is 2nd phase. It is the figure which showed an example of the output spectrum of the multicarrier signal I2 output in a container part. (A) is the figure which showed an example of the output spectrum of the signal output from the frequency conversion part which concerns on this Embodiment, (b) is with respect to a speaker from the audio complementation apparatus which concerns on this Embodiment. It is the figure which showed an example of the output spectrum of the signal output. (A) is the figure which showed the other example of the output spectrum of the signal output from the frequency conversion part which concerns on this Embodiment, (b) is a speaker from the audio complementation apparatus which concerns on this Embodiment. It is the figure which showed the other example of the output spectrum of the signal output with respect to.

  Hereinafter, an audio complementing apparatus which is an example of a sound source signal complementing apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of an audio complementing apparatus according to the present embodiment. The audio complementing apparatus 1 includes a first LPF (Low-pass filter) unit (second filter means) 2, a downsampling unit 3, a frequency converting unit 4, an amplifying unit 5, an upsampling unit 6, and a second LPF unit. 7, a first addition unit 8, and a first delay unit 9.

  The first LPF unit 2 has a role as a low-pass filter that extracts a low-frequency component from the sound source signal output from the sound source unit (sound source unit) 11, and the down-sampling unit 3 The sound source signal that has been extracted (the sound source signal that has been filtered by the first LPF unit 2) has a role of down-sampling at predetermined intervals. Note that the cut-off frequency of the low-pass filter in the first LPF unit 2 is set to a frequency equal to or lower than the band that can be reproduced by the speaker 12.

  The frequency conversion unit 4 has a role of supplementing specific low-frequency sounds. FIG. 2 is a block diagram showing a schematic configuration of the frequency conversion unit 4. The frequency conversion unit 4 includes a first phase shifter unit (first phase unit) 21, a multicarrier signal generation unit 22, a first multiplication unit (first multiplication unit) 23, and a second multiplication unit (second multiplication unit). ) 24, a phase inverting unit (phase inverting unit) 25, and a second adding unit (adding unit) 26.

  The first phase shifter unit 21 has a role of generating a 0-degree phase sound source signal I1 and a 90-degree phase sound source signal Q1 with respect to the sound source signal input from the downsampling unit 3. Specifically, the first phase shifter unit 21 includes a Hilbert transform unit 31 and a second delay unit 32 as shown in FIG. The Hilbert transform unit 31 is composed of an n-tap FIR filter, converts the phase of the input sound source signal by 90 degrees, and outputs it as the sound source signal Q1. On the other hand, the second delay unit 32 has a role of performing delay correction by applying the delay generated in the sound source signal Q1 to the sound source signal I1 by the processing in the Hilbert transform unit 31. The second delay unit 32 only performs delay processing on the sound source signal I1, and does not actively perform phase conversion. For this reason, the phase of the sound source signal I1 output from the second delay unit 32 is not changed (becomes 0 degree phase), and as a result, the sound source signal Q1 has a phase difference of 90 degrees with respect to the sound source signal I1. become.

  The multicarrier signal generator 22 has a role of generating an impulse train having a predetermined interval. As shown in FIG. 3B, the multicarrier signal generation unit 22 includes a pulse generation unit (pulse generation unit) 41, an HPF (High-pass filter) unit 42, and a third LPF unit (first filter unit) 43. And a second phase shifter section (second phase means) 44.

  As shown in FIG. 4A, the pulse generation unit 41 has a role of generating an impulse train for every k samples, and the HPF unit 42 outputs an impulse output at regular intervals in the pulse generation unit 41. It has the role of removing the DC component of the column. The third LPF unit 43 is a low-pass filter, and has a role of weighting the frequency of the impulse train in order to generate a complementary sound that does not feel uncomfortable on hearing. Specifically, the third LPF unit 43 performs weighting by adjusting the output level (signal level) of the impulse train according to the frequency band. This weighting can be adjusted by changing the cutoff frequency and the order in the third LPF unit 43.

  The second phase shifter unit 44 has a role of generating a 0 degree phase multicarrier signal I2 and a 90 degree phase multicarrier signal Q2 with respect to the multicarrier signal that has passed through the third LPF unit 43. The specific configuration of the second phase shifter unit 44 is the same as that of the first phase shifter unit 21, and includes a Hilbert transform unit 31 and a second delay unit 32. Similarly to the first phase shifter unit 21, the second phase shifter unit 44 converts the phase of the multicarrier signal input from the third LFP unit 43 by 90 degrees in the Hilbert conversion unit 31, and outputs it as a multicarrier signal Q2. The second delay unit 32 outputs a multicarrier signal I2 by performing delay processing on the multicarrier signal input from the third LFP unit 43 without performing phase conversion. By such processing of the Hilbert transform unit 31 and the second delay unit 32, the multicarrier signal Q2 has a phase difference of 90 degrees with respect to the multicarrier signal I2.

  The first multiplier 23 performs multiplication processing on the 0-degree sound source signal I1 output from the first phase shifter 21 and the 0-degree multicarrier signal I2 output from the multicarrier signal generator 22. Is called. Similarly, the 90-degree phase sound source signal Q1 output from the first phase shifter unit 21 and the 90-degree phase multicarrier signal Q2 output from the multicarrier signal generation unit 22 are the second multiplication unit 24. Multiplication processing is performed at. Then, after the phase inversion of the signal (second complementary signal) that has been subjected to the arithmetic processing by the second multiplication unit 24 is performed in the phase inversion unit 25, the second addition unit 26 performs multiplication in the first multiplication unit 23. The processed signal (first complementary signal) and the signal subjected to phase inversion in the phase inversion unit 25 are added and output to the amplification unit 5.

  In this way, the multi-carrier signal I2 output from the pulse generation unit 41 and weighted by the third LPF unit 43 is multiplied by the sound source signal I1, so that the low band is frequency-shifted to a plurality over a predetermined frequency band. Can be generated. Further, a signal that is 90 degrees in phase with respect to a signal that has undergone bass correction (a signal that has been subjected to multiplication processing by the first multiplication unit 23) and that has been subjected to bass correction by the second multiplication unit 24 in the same manner. By adding the phase inverted by the phase inverter 25, it is possible to effectively suppress the mirror image of the output low frequency signal (complementary signal).

  In addition, since the multicarrier signal output from the multicarrier signal generation unit 22 is generated based on the impulse train, a simple configuration can be achieved without generating and synthesizing a plurality of sine waves having different frequencies and phases. Thus, it is possible to generate a low frequency signal (complementary signal) shifted in frequency over a predetermined frequency band.

  The amplifying unit 5 has a role of amplifying the frequency-shifted low-frequency signal, and the up-sampling unit 6 has a role of up-sampling the low-frequency signal amplified by the amplifying unit 5 at a predetermined interval. Have. The second LPF unit 7 is a low-pass filter, and has a role of removing a plurality of alias signals generated by the upsampling process in the upsampling unit 6.

  On the other hand, the first delay unit 9 has a role of performing delay correction of the sound source signal. By the delay correction by the first delay unit 9, it is possible to add a correction for the delay caused by the downsampling unit 3, the frequency conversion unit 4, and the like to the sound source signal. Then, the low frequency signal generated by the frequency conversion unit 4 or the like is added to the sound source signal subjected to the delay correction by the first delay unit 9 by the first addition unit 8 to complement the low frequency sound. The broken sound source signal is output to the speaker 12.

  Next, a specific operation example of the audio complementing apparatus 1 will be described by showing detailed setting data.

  First, as the numerical setting of each data, the sampling frequency of the sound source is set to 44.1 kHz, and the cut-off frequency is set to 80 Hz using a 6th-order Butterworth low-pass filter as the first LPF unit 2 and the second LPF unit 7. Further, the downsample of the downsampling unit 3 is 1/120, the amplification factor of the amplification unit 5 is 120 times, and the upsample of the upsampling unit 6 is 120 times. When a sound source signal having a sampling frequency of 44.1 kHz is input from the sound source unit 11 to the audio complementing device 1 in which each data is set in this manner, the sampling frequency of the sound source signal is determined by the down-sampling unit 3. Conversion from 44.1 kHz to 367.5 Hz is performed by the down-sampling process, and conversion from 367.5 Hz to 44.1 kHz is performed by the up-sampling process in the up-sampling unit 6.

  Further, the sampling frequency of the pulse generation unit 41 is set to 367.5 Hz similarly to the down-sampled sound source signal, and the generation of the impulse train is set every 16 samples. The HPF unit 42 uses a first-order Butterworth high-pass filter and sets 0.05 as a normalized cutoff frequency. Further, the third LPF unit 43 uses a second-order Butterworth low-pass filter and sets a normalized cutoff frequency of 0.2. Further, the FIR filter of the Hilbert transform unit 31 is set to 32 tap, and the coefficients are as shown in FIG. Further, the delay time of the second delay unit 32 is set to 16 samples.

  FIG. 4B is a diagram showing an output spectrum of an impulse train generated by the pulse generator 41 under the setting conditions as described above. As shown in FIG. 4B, the interval between the impulse trains is 1/16 of 367.5 Hz that is the sampling frequency of the pulse generator 41 (because the impulse train is generated every 16 samples), Thus, a multi-carrier signal is constituted by the impulse train with an interval of 23 Hz.

  FIG. 6A shows the output waveform of the first phase shifter unit 21 (output waveform of the sound source signal I1 and the sound source signal Q1) when the sound source signal is a sine wave of 40 Hz, and FIG. The output spectrum of the 1 phase shifter unit 21 (only the sound source signal I1) is shown. As is clear from FIG. 6A, the output signal of the first phase shifter unit 21 is the sound source signal I1 that is a 0 degree phase sine wave and the sound source signal Q1 that is a 90 degree phase sine wave. The In FIG. 6B, only the output spectrum of only the sound source signal I1 is shown, but the sound source signal Q1 only shows a similar output spectrum because it is different in phase from the sound source signal I1.

  On the other hand, FIG. 7A shows the output waveform of the second phase shifter unit 44 (the output waveform of the multicarrier signal I2 and the multicarrier signal Q2), and FIG. 7B shows the second phase shifter unit 44. Output spectrum (only the multicarrier signal I2 is shown but the multicarrier signal Q2 is also the same). As is clear from FIG. 7A, the output signal of the second phase shifter unit 44 includes a multicarrier signal I2 that is a 0-degree sine wave and a multicarrier signal Q2 that is a 90-degree sine wave. Is output.

  Further, as shown in FIG. 7B, the output spectrum value is weighted according to the cutoff frequency and the order set in the third LPF unit 43. In FIG. 7B, the lower the frequency, the higher the output level of the output spectrum, and the weighting is performed such that the output level of the output spectrum is reduced as the frequency increases. As shown in FIG. 7B, the output spectrum of the multicarrier signal I2 (Q2) output from the second phase shifter unit 44 is composed of an impulse train whose output level is projected at predetermined frequency intervals. The multi-carrier signal I2 (Q2) configured in this way is multiplied by the sound source signal I1 (Q1) whose output level protrudes only at 40 Hz, as shown in FIG. 6B.

  FIG. 8A shows the output spectrum of the low frequency signal output from the frequency converter 4. When the sound source signal is a sine wave of 40 Hz, as shown in FIG. 8A, 63 Hz, 86 Hz, 109 Hz,... Shifted by 23 Hz, 46 Hz, 69 Hz,. A plurality of sine waves are generated, and the mirror image is also effectively suppressed. In this way, by generating a plurality of waveform signals that are frequency-shifted based on the waveform signal of a predetermined frequency in the frequency converter 4, it is possible to obtain an output spectrum of the surrounding frequencies with the predetermined frequency as a reference It becomes. For this reason, it is possible to complement the sound source signal in a predetermined frequency band range.

  FIG. 8B is a diagram illustrating an output spectrum of a signal output from the audio complementing apparatus 1 to the speaker 12. Specifically, the plurality of sine waves shown in FIG. 8A is a sound source signal input from the sound source unit 11 after being filtered by the second LPF unit 7 as shown in FIG. The sound source signal delayed in the 1 delay unit 9 is combined with the first adder 8. In this way, a signal having a predetermined frequency interval and a weighted output spectrum is synthesized with the sound source signal input from the sound source unit 11 as shown in FIG. 8B. Thus, it is possible to generate a signal (low frequency signal) in which the low frequency component is emphasized.

  In this way, after the impulse generator 41 generates an impulse train of predetermined frequency intervals and performs predetermined weighting, the addition processing (synthesis processing) is performed on the sound source signal in the frequency band to be corrected. Thus, it is possible to generate a complementary signal that emphasizes (complements) the output level around a predetermined frequency band.

  Further, in the audio complementing apparatus 1 according to the present embodiment, the output level in a specific frequency band can be complemented using the impulse train generated by the pulse generating unit 41, so that the signal level of the sound source signal (output) Therefore, it is possible to perform complementation without being influenced by the signal level of the sound source signal as in the case of generating a harmonic overtone and complementing the sound source signal. The effect can be complemented by a desired signal level in the frequency band range.

  As described above, the audio source complementing apparatus 1 according to the present invention has been described by exemplifying the audio complementing apparatus 1 according to the above-described embodiment, but the sound source signal complementing apparatus according to the present invention is described above. It is not limited to the example shown in the form. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in FIGS. 4 to 8 described above, the case where the sound source signal is a sine wave of 40 Hz has been described, but the sound source signal is not limited to the case of a sine wave of 40 Hz. For example, in FIG. 9A, the sound source signal is composed of a 40 Hz sine wave and a 55 Hz sine wave, and the output spectrum of the 55 Hz sine wave is smaller by −6 dB than the output spectrum of the 40 Hz sine wave. FIG. 9B shows the output spectrum of the signal output from the audio complementing apparatus 1 to the speaker 12.

  Comparing FIG. 9 (a) and FIG. 8 (a), in the output spectrum shown in FIG. 9 (a), in addition to the output spectrum shown in FIG. A plurality of sine waves of 78 Hz, 101 Hz, 124 Hz,... Shifted by 23 Hz, 46 Hz, 69 Hz,. In this way, even when a sound source signal is composed of a signal waveform composed of a plurality of frequencies, it is possible to perform low-frequency signal complement processing corresponding to each frequency, and the signal characteristics of the sound source signal can be improved. Appropriate complementation can be performed accordingly.

  Furthermore, in the audio complementing apparatus 1 according to the present embodiment, the case where the bass sound of the sound source signal is compensated by correcting the low frequency sound below the reproduction capability of the speaker to the low frequency range that can be reproduced by the speaker 12 has been described. The sound range that can be complemented in the sound source signal complementing apparatus according to the present invention is not limited to the bass part. For example, instead of the low-pass filter of the first LPF unit 2 shown in FIG. 1, by using a band-pass filter that extracts the mid-range and the high-range, the same processing and configuration as in the embodiment, It is possible to complement the sound source signal in the high sound range. By complementing the sound source signal in such a middle sound range and high sound range, for example, it is deleted from the sound source signal at the time of compression by a compression sound source method such as MP3 (MPEG Audio Layer-3) or WMA (Windows (registered trademark) Media Audio). In addition, it is possible to perform acoustic supplementation for mid- and high-frequency sounds.

1 ... Audio complement device (sound source signal complement device)
2 ... 1st LPF part (2nd filter means)
DESCRIPTION OF SYMBOLS 3 ... Downsampling part 4 ... Frequency conversion part 5 ... Amplifying part 6 ... Upsampling part 7 ... 2nd LPF part 8 ... 1st addition part 9 ... 1st delay part 11 ... Sound source part (sound source means)
12 ... Speaker 21 ... 1st phase shifter part (1st phase means)
22... Multicarrier signal generator 23... First multiplier (first multiplier)
24 ... 2nd multiplication part (2nd multiplication means)
25 ... Phase inversion unit (phase inversion means)
26 ... 2nd addition part (addition means)
31 ... Hilbert transform unit 32 ... second delay unit 41 ... pulse generation unit (pulse generation means)
42 ... HPF part 43 ... 3rd LPF part (1st filter means)
44 ... 2nd phase shifter part (2nd phase means)
I1, Q1 ... sound source signals I2, Q2 ... multicarrier signals

Claims (4)

Pulse generation means for generating a signal composed of an impulse train of a predetermined frequency interval;
First filter means for adjusting a signal level of an impulse train of the signal generated by the pulse generating means to generate a multicarrier signal according to a frequency band;
A sound source signal complementing device, comprising: first multiplication means for generating a first complementary signal by multiplying the sound source signal output from the sound source means by the multicarrier signal. A second filter unit that performs a filtering process by extracting a signal output of a predetermined frequency band for the sound source signal output from the sound source unit;
2. The sound source signal complementing apparatus according to claim 1, wherein the first multiplying unit multiplies the multicarrier signal by the sound source signal that has been subjected to the filter processing by the second filter unit. 3. The sound source according to claim 2, wherein the second filter unit performs the filtering process so that a signal output of a frequency band that can be reproduced in a speaker for outputting the sound source signal is extracted. Signal complementer. First phase means for generating a 0 degree phase sound source signal I1 and a 90 degree phase sound source signal Q1 based on the sound source signal;
Second phase means for generating a 0 degree phase multicarrier signal I2 and a 90 degree phase multicarrier signal Q2 based on the multicarrier signal;
Second multiplication means for generating a second complementary signal by multiplying the multi-carrier signal Q2 by the sound source signal Q1,
Phase inversion means for performing phase inversion of the second complementary signal generated by the second multiplication means;
The second complementary signal phase-inverted by the phase inverting means is added to the first complementary signal generated in the first multiplying means by multiplying the sound source signal I1 by the multi-carrier signal I2. 4. The sound source signal complementing device according to claim 1, further comprising: an adding unit configured to generate a complementary signal.

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