CN101727907A - Audio-frequency processing circuit, audio-frequency processing device and method - Google Patents
Audio-frequency processing circuit, audio-frequency processing device and method Download PDFInfo
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- CN101727907A CN101727907A CN200910209920A CN200910209920A CN101727907A CN 101727907 A CN101727907 A CN 101727907A CN 200910209920 A CN200910209920 A CN 200910209920A CN 200910209920 A CN200910209920 A CN 200910209920A CN 101727907 A CN101727907 A CN 101727907A
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/0208—Noise filtering
- G10L21/0216—Noise filtering characterised by the method used for estimating noise
- G10L21/0232—Processing in the frequency domain
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Processing of the speech or voice signal to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/0272—Voice signal separating
- G10L21/028—Voice signal separating using properties of sound source
Abstract
The invention relates to an audio-frequency processing circuit, audio-frequency processing device and method. The audio-frequency processing circuit comprises: a frequency dividing circuit for dividing the input signal into a plurality of frequency bands to generate a plurality of first audio-frequency signals; a plurality of compression circuits for performing non-linear process of the first audio-frequency signals to generate a plurality of second audio-frequency signals; and an additive operation circuit for adding the second audio-frequency signals to generate an output signal. Each compression circuit multiplies the first audio-frequency signals by the gain determined by the preset coefficient to generate the second audio-frequency signals. Thus the output signal is changed into the frequency character of a voice speaker to be corrected. In addition, the audio-frequency signals with excellent auditory-sensation acoustics performance are generated without high-performance circuit and S.N ratio deterioration and with distortion suppression.
Description
Technical field
The present invention relates to a kind of audio frequency processing circuit, apparatus for processing audio and audio-frequency processing method, it is by the gain adjustment in the audio-band of carrying out sound signal, and improves sense of hearing sound equipment (audio acoustics).
The spy who the present invention is based on Japanese patent application is willing to 2008-278923 number, and (applying date: on October 29th, 2008) require right of priority, its content is quoted in this article.
Background technology
In recent years, be accompanied by the development of mobile communications devices such as mobile phone, develop various audio signal processing techniques, in various documents such as patent documentation 1, disclose.
Patent documentation 1: No. the 3775156th, Jap.P.
In patent documentation 1 disclosed mobile phone, for volume balance the incoming call melody that is made of a plurality of parts is regenerated with the best, utilize balanced device to adjust the frequency characteristic of note signal, make the frequency characteristic flatization of loudspeaker (or receiver).
Usually, realize the planarization of frequency characteristic by the low level in the frequency characteristic of loudspeaker partly being improved gain.Under the sound signal of high level was input to situation in the balanced device, the circuit of balanced device or its back segment must adopt high performance circuit, to be used to handle the input audio signal of high level.On the other hand, if low level sound signal is input in the balanced device, then the S/N of sound reproduction is than descending.Therefore, the audio signal processing technique put down in writing of patent documentation 1 is difficult to be applied to mobile phone.
Summary of the invention
The object of the present invention is to provide a kind of audio frequency processing circuit, apparatus for processing audio and audio-frequency processing method that does not adopt high performance circuit just can improve sense of hearing sound equipment.
Audio frequency processing circuit involved in the present invention has: frequency dividing circuit, and it is divided into a plurality of frequency bands with input signal, generates a plurality of the 1st sound signals; A plurality of compressor circuits, it implements Nonlinear Processing to a plurality of the 1st sound signals, generates a plurality of the 2nd sound signals; And adder operation circuit, it generates output signal with a plurality of the 2nd sound signal additions.Each compressor circuit multiply by the gain of determining based on predetermined coefficients to the 1st sound signal, generates the 2nd sound signal.
In above-mentioned audio frequency processing circuit, carry out following Nonlinear Processing: low level input signal is improved gain, to the input signal reduction gain of high level.In addition, because can be, proofread and correct, therefore can generate the audio frequency output of sense of hearing sound equipment excellence with frequency characteristic to the loudspeaker that output signal is transformed to sound etc. from outside specified coefficient.In addition, because the 1st sound signal be multiply by based on the 1st audio signal level and predetermined coefficients and definite gain, generate the 2nd sound signal, therefore, with compare for the Comparative Examples (with reference to Fig. 4) of the sound signal correcting frequency characteristic after the Nonlinear Processing being carried out the gain multiplied computing, the S/N that can not make output signal in the present invention is than deterioration and suppress distortion.
Each compressor circuit has: level detection portion, and it detects the 1st Audio Meter; Coefficient portion, it multiply by predetermined coefficients to detected level; The gain determination portion, its multiplication result based on this coefficient portion is determined gain; And multiplying portion, it multiply by the gain of determining to the 1st sound signal, generates the 2nd sound signal.In addition, each compressor circuit has storage part, its refreshable ground store predetermined coefficient.
Apparatus for processing audio involved in the present invention has above-mentioned audio frequency processing circuit and is used for its output signal is transformed to the loudspeaker of sound, and predetermined coefficients is set at the frequency characteristic that is used for loudspeaker and proofreaies and correct.
In audio-frequency processing method involved in the present invention, input signal is divided into a plurality of frequency bands, generates a plurality of the 1st sound signals, a plurality of the 1st sound signals are implemented Nonlinear Processing, generate a plurality of the 2nd sound signals, a plurality of the 2nd sound signal additions are generated output signal.In above-mentioned Nonlinear Processing, the 1st sound signal be multiply by based on the 1st Audio Meter and predetermined coefficients and definite gain generates the 2nd sound signal.
Description of drawings
Fig. 1 is the block diagram of the structure of the related apparatus for processing audio of expression present embodiment.
Fig. 2 is the block diagram of the structure of the expression compressor circuit that apparatus for processing audio had.
Fig. 3 is the curve map of the input and output level nature of expression compressor circuit.
Fig. 4 is the block diagram of expression as the structure of the apparatus for processing audio of the Comparative Examples of apparatus for processing audio shown in Figure 1.
Fig. 5 represents the input and output level nature of audio frequency processing circuit, is to be used for being associated with table 1 and table 2 and the curve map of the validity of the present embodiment of comparing with Comparative Examples is described.
Fig. 6 is the block diagram of the structure of the related audio frequency processing circuit of the variation of expression present embodiment.
Embodiment
Describe the present invention in detail with reference to accompanying drawing and with embodiment.
Fig. 1 is the block diagram of the structure of the related apparatus for processing audio 100 of expression present embodiment.Apparatus for processing audio 100 is made of audio frequency processing circuit 1 and loudspeaker 2.1 pair of sound signal of audio frequency processing circuit is the Audio Processing that input signal IN implements regulation, generates output signal OUT.Loudspeaker 2 is transformed to output signal OUT sound and exports (playback).Apparatus for processing audio 100 for example is assembled in the mobile phone, and input signal IN is user's the sound signal of the opposite side mobile phone of ongoing communication.By the Audio Processing of audio frequency processing circuit 1, and loudspeaker 2 is exported the sound that sense of hearing sound equipment is improved.
Audio frequency processing circuit 1 has frequency dividing circuit 10, compressor circuit unit 20 and adder operation circuit 30.Frequency dividing circuit 10 is divided into a plurality of frequency bands with input signal IN, generates a plurality of the 1st sound signals.20 pairs of a plurality of the 1st sound signals in compressor circuit unit are implemented dynamic range compression (Dynamic Range Compression) respectively, generate a plurality of the 2nd sound signals.Adder operation circuit 30 generates output signal OUT with a plurality of the 2nd sound signal additions.
Loudspeaker 2 has the intrinsic frequency characteristic of this loudspeaker.In the present embodiment, in order to improve the sense of hearing sound equipment of the sound reproduction that is undertaken by loudspeaker 2, consider the intrinsic frequency characteristic of loudspeaker 2 and give the frequency characteristic of regulation to output signal OUT.Therefore, each compressor circuit uses the control signal CTL that supplies with from the outside of audio frequency processing circuit 1 to implement treatment for correcting.Control signal CTL suitably determines with the frequency characteristic that should give on output signal OUT.In the present embodiment, control signal CTL and prescribed coefficient corresponding with the natural frequency characteristic of loudspeaker 2, subtend gain calculating portion 52 signal supplied level are adjusted (with reference to Fig. 2) in each compressor circuit.Gain calculating portion 52 is corresponding with institute signal supplied level and therefore calculated gains gives the frequency characteristic corresponding with coefficient to output signal OUT.That is, in the present embodiment, set coefficient in order accordingly the frequency characteristic of loudspeaker 2 to be proofreaied and correct with output signal OUT.The employed coefficient of this treatment for correcting is specified from the outside of audio frequency processing circuit 1, but the supply source of control signal CTL also can be positioned at the outside or inner of apparatus for processing audio 100.
Below, the structure of each compressor circuit is described with reference to Fig. 2.Therefore the 1st compressor circuit U1 to the 6 compressor circuit U6 have identical structure respectively, here the structure of the 1st compressor circuit U1 are described.
As shown in Figure 2, the 1st compressor circuit U1 has level detection portion 50, coefficient portion 51, gain calculating portion (or gain determination portion) 52 and multiplying portion 53.50 pairs of the 1st Audio Meters that generated by BPF 1 of level detection portion detect.51 pairs of detected the 1st Audio Meters of coefficient portion multiply by the specified coefficient by control signal CTL.This multiplying is used to proofread and correct the frequency characteristic of loudspeaker 2 and carries out.Also can make in the coefficient portion 51 to have storage part, and refreshable ground storage coefficient.In coefficient portion 51, do not have under the situation of storage part, make in the supply source of control signal CTL to have storage part, and refreshable ground storage coefficient.Gain calculating portion 52 has the gain table that is used for determining the gain corresponding with this input signal.That is, gain calculating portion 52 is based on the output signal and the gain table calculated gains of coefficient portion 51.This gain table as described later shown in, be designed to make the relation between incoming level and the output level to have nonlinear characteristic, be responsible for the Nonlinear Processing in the compressor circuit.The gain of being calculated by gain calculating portion 52 will be multiply by by the 1st sound signal that BPF 1 generates in multiplying portion 53, generate the 2nd sound signal.In addition, gain is proofreaied and correct the frequency characteristic of loudspeaker 2 and is calculated, so treatment for correcting is finished by the multiplying of multiplying portion 53.In other words, the 1st compressor circuit U1 also has the function of correction processing circuit.
Each compressor circuit has the input and output level nature shown in the solid line of Fig. 3.Described gain table is set at and can obtains this input and output level nature.In Fig. 3, transverse axis is represented incoming level (dB), and the longitudinal axis is represented output level (dB).The level that label " UCL " expression is acoustically uncomfortable, it is equivalent to can not make the people to produce the higher limit of the acoustic pressure scope of sense of discomfort acoustically.The UCL value can be set arbitrarily, but preferably utilizes statistical method to set.Shown in the input and output level nature of Fig. 3, under the situation of incoming level more than or equal to the UCL value, each compressor circuit limits output level and is fixed as the UCL value.Thus, the 2nd sound signal is restricted to can not makes the people produce the acoustic pressure of sense of discomfort acoustically.
In Fig. 3, label " HTL " expression threshold of audibility, it is equivalent to the lower limit of the acoustic pressure scope that the people can listen to.The HTL value can be set arbitrarily, but preferably utilizes statistical method to set.In addition, label " HTL_high " expression exceeds the level of regulation residual quantity (dB) than the HTL value, and is to set in the scope of HTL_high＜UCL.In Fig. 3, dotted line is the straight line that links between incoming level/output level (UCL, UCL) point and the initial point, shows linear input and output level nature.Compare with linear input and output level nature shown in dotted lines in Figure 3 and can be clear and definite, the input and output level nature of each compressor circuit of being represented by solid line is non-linear.
Input and output level nature according to each compressor circuit, 2nd audio signal level of the 1st audio signal level (being incoming level) boil down to till will be from the HTL value to the UCL value till from the HTL_high value to the UCL value, can make threshold of audibility is that the listener of HTL_high value also clearly listens to from more than or equal to 1st sound signal of HTL value till the HTL_high value.
In the treatment for correcting of the frequency characteristic of loudspeaker 2, for its frequency characteristic, need in the low level zone, improve gain, in the high level zone, reduce gain.Gain calculating portion 52 decision gains by coefficient portion 51 back segments shown in Figure 2.Gain calculating portion 52 compresses amplification, so that incoming level is low more, just improve gain more, coefficient will be multiply by by level detection portion 50 detected the 1st audio signal levels in coefficient portion 51, calculate corresponding to the increase and decrease amount in the 1st audio signal level and the loudspeaker 2 thus and level after increasing or reducing.That is, make in loudspeaker 2 under the situation of level decay, the multiplication computing of usage factor portion 51 makes the left skew of incoming level in Fig. 3 of gain calculating portion 52.On the other hand, under the situation of in loudspeaker 2, level being amplified, make the right-hand skew of incoming level in Fig. 3 of gain calculating portion 52.
As mentioned above, each compressor circuit has nonlinear input and output level nature,, it is characterized in that carrying out simultaneously Nonlinear Processing and treatment for correcting here.Thus, can prevent overflowing in the adder operation circuit 30, and improve the S/N ratio of output signal OUT.Fig. 4 is illustrated in the structure of carrying out the apparatus for processing audio 200 of treatment for correcting after the Nonlinear Processing.With this apparatus for processing audio 200 as a comparison case, feature and the advantage to the related apparatus for processing audio 100 of present embodiment describes.
Apparatus for processing audio 200 shown in Figure 4 is made of audio frequency processing circuit 3 and loudspeaker 2.Audio frequency processing circuit 3 has frequency dividing circuit 10, compressor circuit unit 40, gain multiplied operational part G1 to G6 and adder operation circuit 30.Compressor circuit unit 40 has a plurality of compressor circuits (i.e. the 11st compressor circuit U11 to the 16 compressor circuit U16), and they are connected respectively accordingly with the BPF 1 to BPF 6 that frequency dividing circuit 10 is comprised.The 11st compressor circuit U11 to the 16 compressor circuit U16 have the structure after the removal coefficient portion 51 from the structure shown in Fig. 2 respectively, and the 1st sound signal that the bandpass filter (BPF) by correspondence generates is implemented Nonlinear Processing, generate the 3rd sound signal.
Gain multiplied operational part G1 to G6 for example is made of balanced device, is connected accordingly with the 11st compressor circuit U11 to the 16 compressor circuit U16.In gain multiplied operational part G1 to G6, supply with described control signal CTL.The 3rd sound signal that each gain multiplied operational part will be generated by the compressor circuit of correspondence multiply by the specified coefficient of control signal CTL, generates the 2nd sound signal.The coefficient multiplying that utilizes gain multiplied operational part G1 to G6 to carry out is used for the frequency characteristic of loudspeaker 2 proofreaied and correct and carries out, and specifically, carries out in the mode of offsetting the level increase and decrease amount in the loudspeaker 2.Like this, apparatus for processing audio 200 uses gain multiplied operational part G1 to G6 to carry out treatment for correcting.30 pairs of a plurality of the 2nd sound signal additions that generate by gain multiplied operational part G1 to G6 of adder operation circuit generate output signal OUT.
Table 1
| Frequency [Hz] | Frequency characteristic [dB] |
| ??125 | ??-10 |
| ??250 | ??-5 |
| ??500 | ??0 |
| ??1000 | ??-5 |
| ??2000 | ??-7 |
| Frequency [Hz] | Frequency characteristic [dB] |
| ??4000 | ??-10 |
Table 1 illustrates an example of the frequency characteristic of loudspeaker 2, it is being implemented under the situation of treatment for correcting, gain multiplied operational part G1 amplifies the 3rd sound signal with+10dB, gain multiplied operational part G2 amplifies the 3rd sound signal with+5dB, gain multiplied operational part G3 amplifies the 3rd sound signal with 0dB, gain multiplied operational part G4 amplifies the 3rd sound signal with+5dB, and gain multiplied operational part G5 amplifies the 3rd sound signal with+7dB, and gain multiplied operational part G6 amplifies the 3rd sound signal with+10dB.Thus, in audio frequency processing circuit 3, the sound signal of each frequency band and the level damping capacity of loudspeaker 2 are correspondingly amplified.Thus, suppress (removal) and carry out the influence of the intrinsic frequency characteristic of loudspeaker 2 sound of actual playback from loudspeaker 2.
But the frequency characteristic according to the loudspeaker 2 of apparatus for processing audio 200 might make the output level of gain multiplied operational part G1 to G6 too high.In addition, utilizing mimic channel to constitute under the situation of adder operation circuit 30, if the output level of gain multiplied operational part is too high, then output signal OUT can clipped wave (clipping).Utilizing digital circuit to constitute under the situation of adder operation circuit 30, if the output level of gain multiplied operational part is too high, then can overflow, make output signal OUT slicing in the same manner with mimic channel.Its result, output signal OUT produces distortion, tonequality deterioration.In addition, even the output level of gain multiplied operational part is positioned at the dynamic range of adder operation circuit 30, also can produce distortion sometimes owing to the frequency characteristic of the loudspeaker 2 of back segment.
Input to the 3rd audio signal level of each gain multiplied operational part by reduction, can solve the above problems a little, if but reduce the 3rd Audio Meter, then the S/N of output signal OUT is than descending.This situation is to have problems under the situation of little amplitude at input signal IN.In addition, this problem compressor circuit is that mimic channel or digital circuit all take place in the same manner.Utilizing mimic channel to constitute under the situation of compressor circuit, to compare with incoming signal level, noise level (level of for example transistorized thermonoise or the noise that enters from power supply) has problems.Utilizing digital circuit to constitute under the situation of compressor circuit, the round-off error (rounding error) of the position of digital audio-frequency data has problems.
Compare with apparatus for processing audio 200 as a comparison case, in the related apparatus for processing audio 100 of present embodiment, in compressor circuit, carry out Nonlinear Processing and treatment for correcting.Specifically, proofread and correct by level detection portion 50 detected the 1st audio signal levels by 51 pairs in coefficient portion, based on the level after this correction, calculate the gain of giving to the 1st sound signal by gain calculating portion 52,53 pairs the 1st sound signals of multiplying portion multiply by the gain that calculates and generate the 2nd sound signal.Gain calculating portion 52 is according to nonlinear input and output level nature decision gain shown in Figure 3.That is,, reduce gain and compression of dynamic range for the higher part of the 1st audio signal level.Thus, even utilize compressor circuit to carry out treatment for correcting, also can be suppressed to produce in the adder operation circuit 30 and overflow.Especially, in input-output characteristic shown in Figure 3, because the 2nd audio signal level suppresses for not surpassing the UCL value, therefore, the maximum level of the 2nd sound signal of exporting from the 1st compressor circuit U1 to the 6 compressor circuit U6 is determined.Therefore, set the dynamic range of adder operation circuit 30, can prevent from reliably to cause taking place distortion by the slicing of output signal OUT by considering maximum level.In addition, even input signal IN is little amplitude,, therefore can not cause S/N than descending because present embodiment does not need its level of further decaying yet.
Below, be conceived to the signal path corresponding with BPF6, the difference of the result of use between apparatus for processing audio 100 and the apparatus for processing audio 200 is described.Here, in the input and output level nature of the related input and output level nature of the Nonlinear Processing of the 6th compressor circuit U6 shown in Fig. 5 and the table 2, the 16th compressor circuit U16 and the incoming level-gain characteristic of gain multiplied operational part 52.In Fig. 5, the decibel counting applying unit " dBSPL " as sound pressure level is made as 40dB with the difference between HTL value and the HTL_high value, and in addition, the HTL value is-5dB that the UCL value is 100dB.
Table 2
| Incoming level [dBSPL] | Gain [dB] | Output level [dBSPL] |
| ??-10 | ??40 | ??30 |
| ??-5 | ??40 | ??35 |
| ??0 | ??38.1 | ??38.1 |
| ??10 | ??34.3 | ??44.3 |
| ??20 | ??30.5 | ??50.5 |
| ??30 | ??26.7 | ??56.7 |
| ??40 | ??22.9 | ??62.9 |
| ??50 | ??19 | ??69 |
| ??60 | ??15.2 | ??75.2 |
| ??70 | ??11.4 | ??81.4 |
| ??80 | ??7.6 | ??87.6 |
| ??90 | ??3.8 | ??93.8 |
| ??100 | ??0 | ??100 |
At first, illustrate that by level detection portion 50 detected level be the situation of 60dBSPL.In the audio frequency processing circuit 3 of the related apparatus for processing audio 200 of Comparative Examples, the gain of being calculated by the gain calculating portion 52 of the 16th compressor circuit U16 is 15.2dB.Thus, if the frequency characteristic of loudspeaker 2 is smooth, then the acoustic pressure from audio frequency processing circuit 3 outputs is 60+15.2=75.2dBSPL.According to table 1, because gain multiplied operational part G6 and the frequency characteristic damping capacity (10dB) of loudspeaker 2 under 4kHz correspondingly improve gain, so the output acoustic pressure of audio frequency processing circuit 3 becomes 75.2+10-10=75.2dBSPL.This illustrates by the frequency characteristic of 3 pairs of loudspeakers 2 of audio frequency processing circuit and proofreaies and correct with high precision.
Relative therewith, the acoustic pressure of being exported for the audio frequency processing circuit 1 of the related apparatus for processing audio 100 of present embodiment, if the frequency characteristic of loudspeaker 2 is smooth, then the incoming level of the gain calculating portion 52 of the 6th compressor circuit U6 is 60dBSPL, the gain of being calculated by this gain calculating portion 52 is 15.2dB, therefore, above-mentioned acoustic pressure becomes 60+15.2=75.2dBSPL.According to table 1, coefficient portion 51 correspondingly descends at being made by level detection portion 50 detected level to gain with the damping capacity (10dB) of the frequency characteristic of loudspeaker 2 under 4kHz, therefore the incoming level of gain calculating portion 52 is 60-10=50dBSPL, the gain of being calculated by gain calculating portion 52 is 19dB, its result, the output acoustic pressure of audio frequency processing circuit 1 becomes 60+19-10=69dBSPL.This illustrates audio frequency processing circuit 1 with to a certain degree the precision lower than described audio frequency processing circuit 3, and the frequency characteristic of loudspeaker 2 is proofreaied and correct.
Below, illustrate that by level detection portion 50 detected level be the situation of 100dBSPL.In the audio frequency processing circuit 3 of the related apparatus for processing audio 200 of Comparative Examples, the gain of being calculated by the gain calculating portion 52 of the 16th compressor circuit U16 is 0dB.If the frequency characteristic of loudspeaker 2 is smooth, then the output acoustic pressure of audio frequency processing circuit 3 is 100+0=100dBSPL.According to table 1, because the damping capacity (10dB) of gain multiplied operational part G6 and the frequency characteristic of loudspeaker 2 under 4kHz correspondingly improves gain, so the output acoustic pressure of audio frequency processing circuit 3 becomes 100+10-10=100dBSPL.This frequency characteristic that 3 pairs of loudspeakers 2 of audio frequency processing circuit are shown is proofreaied and correct with high precision, but then, expression needs to use the high performance circuit that can handle the high level signal suitable with 110dBSPL as each gain multiplied operational part, adder operation circuit 30 and loudspeaker 2.
Relative therewith, output acoustic pressure for the audio frequency processing circuit 1 of the related apparatus for processing audio 100 of present embodiment, if the frequency characteristic of loudspeaker 2 is smooth, then the incoming level of the gain calculating portion 52 of the 6th compressor circuit U6 is 100dBSPL, in addition, the gain of being calculated by gain calculating portion 52 is 0dB, and therefore, above-mentioned output acoustic pressure is 100+0=100dBSPL.According to table 1, because coefficient portion 51 correspondingly makes the 50 detected level declines by level detection portion with the damping capacity (10dB) of the frequency characteristic of loudspeaker 2 under 4kHz, therefore the incoming level of gain calculating portion 52 is 100-10=90dBSPL, because the gain that gain calculating portion 52 calculates is 3.8dB, so the output acoustic pressure of audio frequency processing circuit 1 becomes 100+3.8-10=93.8dBSPL.This illustrates audio frequency processing circuit 1 with to a certain degree the precision lower than described audio frequency processing circuit 3, and the frequency characteristic of loudspeaker 2 is proofreaied and correct.In addition, expression can be used the circuit that the level signal suitable with 103.8dBSPL handled and constitutes as multiplying portion 53 and loudspeaker 2.
In addition, the Nonlinear Processing that each compressor circuit in the present embodiment is carried out has comprised the level restriction, compression is amplified and linear amplification, but must not be defined in this.In addition, in the present embodiment, as the unit that its output signal OUT is transformed to sound, illustration loudspeaker 2, but must not be defined in this.That is, the present invention is not limited to present embodiment, and comprising can be based on claims limitation of the invention and the problem that should solve and the various design examples of grasping.Below, the variation of present embodiment is described with reference to Fig. 6.
Fig. 6 is the block diagram of the structure of the related audio frequency processing circuit 4 of the variation of expression present embodiment.With the related audio frequency processing circuit 1 of present embodiment in the same manner, the related 4 couples of input signal IN of audio frequency processing circuit of variation implement Audio Processing, generate output signal OUT.Carry out Audio Processing with audio frequency processing circuit 1 in time domain and compare, audio frequency processing circuit 4 is carried out Audio Processing in frequency domain.
Audio frequency processing circuit 4 has Fourier transform unit 60, frequency band selection portion 1 to frequency band selection portion 6, level detection portion 61 to 66, coefficient portion 71 to 76, gain calculating portion 81 to 86, gain interpolation portion 70, multiplying portion 80 and inverse fourier transform portion 90.Audio frequency processing circuit 4 comprises the circuit structure of 6 systems, frequency band selection portion 1, level detection portion 61, coefficient portion 71 and gain calculating portion 81 are connected in series, frequency band selection portion 2, level detection portion 62, coefficient portion 72 and gain calculating portion 82 are connected in series,, frequency band selection portion 6, level detection portion 66, coefficient portion 76 and gain calculating portion 86 are connected in series.
Fourier transform unit 60 is by carrying out Fourier transform (for example fast fourier transform) to input signal IN, and time-domain signal is transformed to frequency-region signal.Select the signal of allocated frequency band to export the input signal IN of each frequency band selection portion behind Fourier transform.In other words, each frequency band selection portion is calculated the input spectrum of allocated frequency band.That is, Fourier transform unit 60 and frequency band selection portion 1 to frequency band selection portion 6 realizes the function suitable with the frequency dividing circuit 10 shown in Fig. 1.
Gain calculating portion 81 to 86 is equivalent to the gain calculating portion 52 shown in Fig. 2 respectively, based on the output signal and gain table (not shown) calculated gains of coefficient portion 71 to 76.Here, gain calculating portion 81 to 86 can be with reference to shared gain table or independent gain table.In this variation,, make gain calculating portion 81 to 86 with reference to independent gain table from improving the angle of precision.
Interpolation is carried out in 70 pairs of gains of being calculated by gain calculating portion 81 to 86 of gain interpolation portion, calculates the relative gain of signal (being the input signal IN of frequency domain) with whole frequency domain.The following describes this " interpolation ".
81 to 86 pairs of gains relative with each special frequency band of gain calculating portion are calculated, and in whole frequency domain, only the gain corresponding with 6 characteristic frequency compositions are calculated.But, in input signal IN, contain the frequency content except 6 characteristic frequency compositions.Therefore, in this variation,, linear interpolation is carried out in the gain relative with 6 frequency contents, thereby the gain relative with the input signal IN of whole frequency domain calculated for the input signal IN of frequency domain.
Multiplying portion 80 is equivalent to the multiplying portion 53 shown in Fig. 2, the input signal IN of frequency domain be multiply by the gain of being calculated by gain interpolation portion 70.The output signal of 90 pairs of multiplying portions 80 of inverse fourier transform portion is implemented inverse fourier transform, thereby the output signal of frequency domain is transformed to the output signal OUT of time domain.
That is, the level detection portion in the audio frequency processing circuit 4 61 to 66, coefficient portion 71 to 76, gain multiplied operational part 81 to 86, gain interpolation portion 70, multiplying portion 80 and inverse fourier transform portion 90 are equivalent to the compressor circuit unit 20 of described audio frequency processing circuit 1.In addition, in apparatus for processing audio, do not need adder operation circuit 30 with related audio frequency processing circuit of this variation 4.
At last, the present invention is not limited to present embodiment and variation etc., comprises the various design example that the audio signal processing technique shown in the appending claims is specialized.
Claims (6)
1. audio frequency processing circuit is characterized in that having:
Frequency dividing circuit, it is divided into a plurality of frequency bands with input signal, generates a plurality of the 1st sound signals;
A plurality of compressor circuits, it implements Nonlinear Processing to aforementioned a plurality of the 1st sound signals, generates a plurality of the 2nd sound signals; And
Adder operation circuit, it generates output signal with aforementioned a plurality of the 2nd sound signal additions,
Aforementioned a plurality of compressor circuit multiply by the gain of determining based on predetermined coefficients to the 1st sound signal separately, generates the 2nd sound signal.
2. audio frequency processing circuit according to claim 1 is characterized in that,
Described coefficient is from outside appointment.
3. audio frequency processing circuit according to claim 1 is characterized in that,
Aforementioned a plurality of compressor circuit has separately: level detection portion, and it detects aforementioned the 1st Audio Meter; Coefficient portion, it multiply by predetermined coefficients to aforementioned detected level; The gain determination portion, its multiplication result based on this coefficient portion is determined gain; And multiplying portion, it multiply by aforementioned determined gain to aforementioned the 1st sound signal, generates aforementioned the 2nd sound signal.
4. audio frequency processing circuit according to claim 1 is characterized in that,
Aforementioned a plurality of compressor circuit has storage part separately, its refreshable ground store predetermined coefficient.
5. an apparatus for processing audio is characterized in that, has audio frequency processing circuit and the loudspeaker that is used for output signal is transformed to sound,
Wherein, this audio frequency processing circuit has: frequency dividing circuit, and it is divided into a plurality of frequency bands with input signal, generates a plurality of the 1st sound signals; A plurality of compressor circuits, it implements Nonlinear Processing to aforementioned a plurality of the 1st sound signals, generates a plurality of the 2nd sound signals; And adder operation circuit, it generates output signal with aforementioned a plurality of the 2nd sound signal additions, and aforementioned a plurality of compressor circuits multiply by the gain of determining based on predetermined coefficients to the 1st sound signal separately, generate the 2nd sound signal,
Predetermined coefficients is set at the frequency characteristic that is used for aforementioned loudspeaker and proofreaies and correct.
6. an audio-frequency processing method is characterized in that,
Input signal is divided into a plurality of frequency bands, generates a plurality of the 1st sound signals,
Aforementioned a plurality of the 1st sound signals are implemented Nonlinear Processing, generate a plurality of the 2nd sound signals,
Aforementioned a plurality of the 2nd sound signal additions are generated output signal,
In described Nonlinear Processing, the 1st sound signal be multiply by based on the 1st Audio Meter and predetermined coefficients and definite gain generates the 2nd sound signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008278923A JP5223595B2 (en) | 2008-10-29 | 2008-10-29 | Audio processing circuit and audio processing method |
| JP2008-278923 | 2008-10-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101727907A true CN101727907A (en) | 2010-06-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910209920A Pending CN101727907A (en) | 2008-10-29 | 2009-10-29 | Audio-frequency processing circuit, audio-frequency processing device and method |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP5223595B2 (en) |
| KR (1) | KR101093280B1 (en) |
| CN (1) | CN101727907A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103618983A (en) * | 2013-10-31 | 2014-03-05 | 惠州超声音响有限公司 | A sound equipment control circuit and a control method thereof |
| CN104469621A (en) * | 2014-12-09 | 2015-03-25 | 青岛歌尔声学科技有限公司 | Anti-interference circuit and method of voice remote controller |
| CN105609115A (en) * | 2015-12-18 | 2016-05-25 | 中国电子科技集团公司第四十一研究所 | Audio analyzer and internal self-calibrating method therefor |
| CN114095836A (en) * | 2020-08-04 | 2022-02-25 | 新唐科技股份有限公司 | Audio processing device and audio processing method |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5531988B2 (en) * | 2011-03-03 | 2014-06-25 | 株式会社Ｊｖｃケンウッド | Volume control device, volume control method, and volume control program |
| TWI623829B (en) * | 2015-12-11 | 2018-05-11 | 富奇想股份有限公司 | Method for collaboration between functional modules, modular functional module, and system |
| JP6703867B2 (en) * | 2016-03-08 | 2020-06-03 | ローム株式会社 | High temperature protection circuit, operating method thereof, and audio signal output device |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0574018U (en) * | 1991-02-20 | 1993-10-08 | フオスター電機株式会社 | Audio digital signal processor |
| JP3295440B2 (en) * | 1991-09-10 | 2002-06-24 | パイオニア株式会社 | Signal processing circuit in audio equipment |
| JP3925572B2 (en) * | 1997-06-23 | 2007-06-06 | ソニー株式会社 | Audio signal processing circuit |
| JP4214607B2 (en) * | 1999-03-23 | 2009-01-28 | ソニー株式会社 | Microphone device |
| JP4256631B2 (en) * | 2002-06-03 | 2009-04-22 | パナソニック株式会社 | Auto gain control device |
| JP4131255B2 (en) * | 2004-07-05 | 2008-08-13 | ヤマハ株式会社 | Audio playback device |
-
2008
- 2008-10-29 JP JP2008278923A patent/JP5223595B2/en not_active Expired - Fee Related
-
2009
- 2009-10-26 KR KR1020090101583A patent/KR101093280B1/en not_active IP Right Cessation
- 2009-10-29 CN CN200910209920A patent/CN101727907A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103618983A (en) * | 2013-10-31 | 2014-03-05 | 惠州超声音响有限公司 | A sound equipment control circuit and a control method thereof |
| CN103618983B (en) * | 2013-10-31 | 2016-09-07 | 惠州超声音响有限公司 | A kind of sound control circuit and control method |
| CN104469621A (en) * | 2014-12-09 | 2015-03-25 | 青岛歌尔声学科技有限公司 | Anti-interference circuit and method of voice remote controller |
| CN104469621B (en) * | 2014-12-09 | 2018-09-11 | 歌尔智能科技有限公司 | A kind of voice remote controller anti-jamming circuit and method |
| CN105609115A (en) * | 2015-12-18 | 2016-05-25 | 中国电子科技集团公司第四十一研究所 | Audio analyzer and internal self-calibrating method therefor |
| CN105609115B (en) * | 2015-12-18 | 2019-06-04 | 中国电子科技集团公司第四十一研究所 | A kind of audio analyzer and its internal method for self-calibrating |
| CN114095836A (en) * | 2020-08-04 | 2022-02-25 | 新唐科技股份有限公司 | Audio processing device and audio processing method |
| CN114095836B (en) * | 2020-08-04 | 2023-12-05 | 新唐科技股份有限公司 | Audio processing device and audio processing method |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20100047804A (en) | 2010-05-10 |
| KR101093280B1 (en) | 2011-12-14 |
| JP5223595B2 (en) | 2013-06-26 |
| JP2010109624A (en) | 2010-05-13 |
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Application publication date: 20100609 |