CN1822513A - Signal/noise ratio improvement method of mobile communication terminal and the mobile communication terminal - Google Patents
Signal/noise ratio improvement method of mobile communication terminal and the mobile communication terminal Download PDFInfo
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- CN1822513A CN1822513A CNA200510109204XA CN200510109204A CN1822513A CN 1822513 A CN1822513 A CN 1822513A CN A200510109204X A CNA200510109204X A CN A200510109204XA CN 200510109204 A CN200510109204 A CN 200510109204A CN 1822513 A CN1822513 A CN 1822513A
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Abstract
The present invention discloses one kind of S/N ratio improving method for mobile communication terminal and the improved mobile communication terminal. The improving method includes the following parts: a Fourier transforming part for performing Fourier transformation on the input signal; a noise predicting part for predicting noise in the Fourier transformed signal; a noise compensating part for noise compensation; an S/N ratio evaluating part for evaluating S/N ratio; a lower S/N ratio predicting part for predicting the S/N ratio in the signal to be transmitted based on the evaluated S/N ratio; a gain calculating part for calculating gain compensation based on the evaluated S/N ratio and predicted S/N ratio; and a gain correcting part. The present invention has the advantages of lowering noise, improving S/N ratio and improving talking quality of high speed voice signal.
Description
Technical field
The present invention relates to signal/noise ratio improvement method and mobile communication terminal thereof in the mobile communication terminal, relate in particular to signal/noise ratio improvement method and mobile communication terminal thereof in a kind of mobile communication terminal that reduces when conversing the noise that takes place with the other side.
Background technology
At present, multiple algorithm has been used in coding and the decoding of mobile communication terminal in order to carry out voice signal, and for above-mentioned each algorithm, can reduce noise in the coding of voice signal and decoding step on which kind of degree is a major subjects.
This is because the outside ambient noise of existence in addition, in order to handle high-speed data, also digital noise can take place in speech data.Therefore, reduce this noise, only use a signal that needs to become an important topic.
Generally speaking, the energy ratio of the signal of handling in the general transmission system such as receiver, amplifier and noise call signal noise ratio (SNR:Signal to Noise Ratio, below " SNR " be equivalent with " signal noise ratio ".)。According to above-mentioned signal noise ratio, can restore high-quality voice signal.
Following brief description signal noise ratio, signal is not an individualism, is entrained in noise mostly.Use SNR to represent this ratio scale.If represent signal power with S, represent noise power with N, then be expressed as 10log10 (S/N).Unit is a decibel (dB).Theoretically, only by the noise figure of receiver or amplifier and the size decision of input signal, room for improvement is very little without exception.But for FM (frequency modulation) or PM (phase modulation) mode, if the size of received signal surpasses certain limit, the SNR of restituted signal then can improve to some extent than the SNR of input.
Fig. 1 has shown the block diagram of the signal/noise ratio improvement method that is used to illustrate prior art.
Each module of Fig. 1 demonstrates the structure that is used to reduce noise, reduction voice signal of original use.It is made of fourier transform portion 10, noise prediction portion 20, SNR Rating and Valuation Department 30, following SNR prediction section 40, gain calculating portion 50.
If is the signal sets of input X (t), X (t) can be expressed as formula so, that is, and and X (t)=s (t)+d (t).Wherein, s (t) refers to the signal of actual needs, the dependency noise that d (t) expression takes place.In addition, can use the signal of y (t) expression output.
The signal of above-mentioned input is imported above-mentioned fourier transform portion 10, and 10 pairs in fourier transform portion is converted to frequency domain needing the equation on the time shaft that signal s (t) and noise d (t) sum constitute to carry out fourier transform by above-mentioned from time-domain.
Then, noise is measured, predict noise by above-mentioned noise prediction portion 20 in the signal of above-mentioned conversion.
In addition, above-mentioned SNR Rating and Valuation Department 30 and above-mentioned below the SNR of signal (it is signal and the noise that needs) of the above-mentioned noise prediction of 40 pairs of SNR prediction section portion 20 transmission assess, predict.
And above-mentioned gain calculating portion 50 compensates according to the signal noise comparison gain (gain) of above-mentioned assessment, prediction, improves signal noise ratio by calculating.
Then, the signal y (t) of output aforementioned calculation.
But there are the following problems for above-mentioned existing signal/noise ratio improvement method.
Though existing method effectively, in the noise that changes at any time in time, if use existing method, then is difficult to accurate prediction signal noise ratio (SNR) in certain noise.That is to say that many difficulties can appear in the noise intensity of following the tracks of dynamic change.Therefore, when the noise intensity of signal calculated noise ratio (SNR) time prediction is big slightly, yield value can be excessive so, causes distorted signals.On the contrary, served as when hanging down prediction signal noise ratio (SNR), then can't obtain high-quality voice signal.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of signal/noise ratio improvement method and mobile communication terminal thereof of mobile communication terminal, by reducing noise, when reduction high speed voice signal, can keep speech quality more clearly.
For achieving the above object, the feature of mobile communication terminal provided by the invention is to comprise following several sections: fourier transform portion, carry out fourier transform to the signal of importing; Noise prediction portion predicts the noise of the signal of above-mentioned fourier transform portion conversion; Noise compensation portion compensates the noise of above-mentioned noise prediction portion prediction; SNR Rating and Valuation Department based on the noise of above-mentioned noise compensation portion compensation, assesses SNR; The SNR prediction section is based on the SNR of above-mentioned SNR Rating and Valuation Department assessment, to below the SNR of the signal that transmits being predicted; Gain calculating portion, the SNR that above commentary is estimated and the SNR of prediction are the basis, the calculated gains compensation; The gain correction portion.
In addition, the feature of signal/noise ratio improvement method provided by the invention is to comprise following several steps: import the signal of the noise that mixing, carry out the step of fourier transform; To the step of predicting through the noise of the signal of above-mentioned fourier transform; In the noise of above-mentioned prediction, multiply by the step that offset compensates; SNR to the noise of above-mentioned compensation assesses, the step of the SNR below the prediction; The following SNR of SNR that above commentary is estimated and prediction is the step of basic calculation gain; Revise the step of the gain of aforementioned calculation.
The present invention improves signal noise ratio by reducing noise, can keep speech quality more clearly when reduction high speed voice signal.
Description of drawings
Fig. 1 is the block diagram that is used to illustrate the signal/noise ratio improvement method of prior art;
Fig. 2 is the block diagram that is used to illustrate the signal/noise ratio improvement method of the embodiment of the invention;
Fig. 3 is the flow chart that is used to illustrate the signal/noise ratio improvement method flow process of the embodiment of the invention.
Wherein, Reference numeral:
100: fourier transform portion 200: noise prediction portion
300: 400:SNR Rating and Valuation Department of noise compensation portion
500: following SNR prediction section 600: gain calculating portion
700: the gain correction portion
Embodiment
With reference to the accompanying drawings, the of the present invention useful embodiment that explanation can the specific implementation above-mentioned purpose.
Fig. 2 is the block diagram that is used to illustrate the signal/noise ratio improvement method of the embodiment of the invention.
Be used to improve the mobile communication terminal of signal noise ratio by fourier transform portion 100, the noise prediction portion 200 that links together with above-mentioned fourier transform portion 100, the noise compensation portion 300 that links together with above-mentioned noise prediction portion 200, the SNR Rating and Valuation Department 400 that links together with above-mentioned noise compensation portion 300, the following SNR prediction section 500 that links together with above-mentioned SNR Rating and Valuation Department 400, above-mentioned SNR Rating and Valuation Department 400, the gain calculating portion 600 that links together with following SNR prediction section 500, the gain correction portion 700 that links together with above-mentioned gain calculating portion 600 constitutes.
At first, input is as the actual needs signal s (t) and the mutual signal X (t) that mixes of dependency noise d (t) of voice signal.
The above-mentioned fourier transform portion 100 that has imported above-mentioned signal X (t) carries out fourier transform as the fourier transform portion 10 of the prior art of Fig. 1, and utilization is expressed as | X
t(k) | with ∠ X
t(k) Fourier function switching signal.At this moment, phasor (phasor) is output as y (t) after gain calculating, | X
t(k) | as the factor (factor) of carrying out the branch be used to reduce noise.
200 pairs in above-mentioned noise prediction portion measures through the noise that above-mentioned fourier transform portion 100 carries out the signal of fourier transform, as the inscape that noise is predicted, as the noise prediction portion 20 of existing Fig. 1, calculate the measured value and the predicted value of noise.
Above-mentioned noise compensation portion 300 is the inscape of appending in the noise prediction portion of existing Fig. 1 as feature of the present invention, below it is elaborated.
As of the present invention to realize, for the multiple noise of too high prediction input neither, the multiple noise of low only prediction input, need a part of tracking noise intensity rightly within the specific limits, therefore, added a noise compensation portion 300, noise compensation portion 300 can measure at above-mentioned noise prediction portion 200, the noise of prediction is used different offsets.
Above-mentioned offset can continuously mate (match) value correspondingly at the noise of change.In order to carry out this step, need noise compensation portion 300.
300 pairs of noises of above-mentioned noise compensation portion compensate employed offset and have used 0 to 1 numeral, calculate by nonlinear function.
At this moment, if multiply by offset 1, so above-mentioned noise prediction portion 200 measures, the noise of prediction is then directly imported above-mentioned SNR Rating and Valuation Department 400, carries out the SNR assessment, 500 couples of SNR of following SNR prediction section predict, above-mentioned gain calculating portion 600 is calculated gains based on this.
On the contrary, if signal is suddenly excessive or too small, above-mentioned noise compensation portion 300 uses the offset littler than 1 in the noise of prediction is measured by above-mentioned noise prediction portion 200, above-mentioned noise transmission through compensation is carried out SNR to above-mentioned SNR Rating and Valuation Department 400 and is assessed, 500 couples of SNR of following SNR prediction section predict, above-mentioned gain calculating portion 600 is calculated gains based on this.
And, after the gain that 600 compensation of the above-mentioned gain calculating of 700 pairs of correction portions of gain portion are calculated is revised, output y (t).
Above-mentioned SNR Rating and Valuation Department 400 is used for part that the signal of above-mentioned noise compensation portion 300 compensation is assessed, because the signal noise ratio of actual needs is different because of whether above-mentioned noise compensation portion 300 compensates, so assess in view of the above.
In addition, 400 assessments of above-mentioned SNR Rating and Valuation Department are through the signal of above-mentioned noise compensation portion 300 compensation, above-mentioned below SNR prediction section 500 based on this, SNR below the prediction.At this moment, because the signal noise ratio of actual needs is different because of whether above-mentioned noise compensation portion 300 compensates, the assessment of above-mentioned SNR Rating and Valuation Department 400 changes thereupon, therefore below the SNR prediction also change.
Above-mentioned gain calculating portion 600 based on the SNR of above-mentioned SNR Rating and Valuation Department 400 assessments and above-mentioned below the SNR of SNR prediction section 500 predictions, calculated gains compensates.
And the gain that the above-mentioned gain calculating of 700 pairs of above-mentioned gain correction portions portion 600 is calculated is finally revised.When carrying out noise compensation, gaining at offset, to revise the value that be multiply by be y (t).
Fig. 3 is used for the improve one's methods flow chart of flow process of signal noise ratio of the present invention (SNR).
At first, signal input mobile communication terminal not only contains the actual needs signal in this signal, and noise (step S10) is also mixing.
The signal of above-mentioned input need be changed to frequency domain for through series of steps such as noise testing in the above-mentioned noise prediction portion 200 and noise predictions, therefore, carries out fourier transform (step S20) in above-mentioned fourier transform portion 100.
Above-mentioned signal through fourier transform in above-mentioned noise prediction portion 200 through measurement, after the step (step S30) of predict noise, in above-mentioned noise compensation portion 300, according to the noise of above-mentioned measurement, prediction, use certain offset, noise is compensated (step S40).At this moment, in above-mentioned compensation process, the feature of offset is: at the noise of above-mentioned noise prediction portion prediction, and coupling continuously in 0 to 1 value.
And, at the noise that above-mentioned SNR Rating and Valuation Department 400 utilizes through compensation, SNR is assessed (step S50), above-mentioned below SNR prediction section 500 based on the SNR of above-mentioned SNR Rating and Valuation Department 400 assessments, the following SNR (step S60) of prediction.Above-mentioned gain calculating portion 600 with the SNR of above-mentioned SNR Rating and Valuation Department 400 assessments and above-mentioned below the following SNR of SNR prediction section 500 predictions be basic calculation gain (step S70).
In addition, the gain (step S80) of above-mentioned offset is revised in the gain that gain correction portion 700 is calculated at above-mentioned gain calculating portion 600.At last, output is through the signal (step S90) after the above-mentioned steps.
In sum, signal/noise ratio improvement method of the present invention has following effect,, by reducing noise, improves signal noise ratio that is, when reduction high speed voice signal, can keep speech quality more clearly.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
Claims (7)
1. mobile communication terminal is characterized in that: comprise following several sections:
Noise prediction portion predicts the noise of the signal that receives;
Noise compensation portion compensates the noise of described noise prediction portion prediction;
Signal noise ratio Rating and Valuation Department based on the noise of described noise compensation portion compensation, assesses signal noise ratio;
Following signal noise ratio prediction section is based on the signal noise ratio of described signal noise ratio Rating and Valuation Department assessment, to below the signal noise ratio of the signal that transmits being predicted;
Gain calculating portion, based on the signal noise ratio of described assessment and the signal noise ratio of prediction, the calculated gains compensation.
2. mobile communication terminal according to claim 1 is characterized in that: also comprise a fourier transform portion: the signal to input carries out fourier transform.
3. mobile communication terminal according to claim 1 is characterized in that: also comprise a gain correction portion: be used for gain is revised.
4. mobile communication terminal according to claim 1 is characterized in that: described noise compensation portion multiply by offset and compensates in the noise of described noise prediction portion.
5. mobile communication terminal according to claim 4 is characterized in that: described offset is the value between 0 to 1.
6. signal/noise ratio improvement method is characterized in that: comprise following several steps:
The step that the noise of the signal that receives is predicted;
In the noise of described prediction, multiply by the step that offset compensates;
Signal noise ratio to the noise of described compensation is assessed, the step of the signal noise ratio below the prediction;
With the signal noise ratio of described assessment and the following signal noise ratio of prediction is the step of basic calculation gain;
Revise the step of the gain of described calculating.
7. signal/noise ratio improvement method according to claim 6 is characterized in that:
In described compensation process, offset mates continuously at the noise of described noise prediction portion prediction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020050012777 | 2005-02-16 | ||
| KR1020050012777A KR20060091970A (en) | 2005-02-16 | 2005-02-16 | Signal to noise ratio improvement method for mobile phone and mobile phone |
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| Publication Number | Publication Date |
|---|---|
| CN1822513A true CN1822513A (en) | 2006-08-23 |
| CN100361401C CN100361401C (en) | 2008-01-09 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB200510109204XA Expired - Fee Related CN100361401C (en) | 2005-02-16 | 2005-10-19 | Signal/noise ratio improvement method of mobile communication terminal and the mobile communication terminal |
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| Country | Link |
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| KR (1) | KR20060091970A (en) |
| CN (1) | CN100361401C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105635453A (en) * | 2015-12-28 | 2016-06-01 | 上海博泰悦臻网络技术服务有限公司 | Conversation volume automatic adjusting method and system, vehicle-mounted device, and automobile |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113467320A (en) * | 2021-07-21 | 2021-10-01 | 西安龙飞电气技术有限公司 | Weak signal detection algorithm based on gain compensation |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5659622A (en) * | 1995-11-13 | 1997-08-19 | Motorola, Inc. | Method and apparatus for suppressing noise in a communication system |
| US7280618B2 (en) * | 2003-06-25 | 2007-10-09 | Interdigital Technology Corporation | Digital baseband receiver including a high pass filter compensation module for suppressing group delay variation distortion incurred due to analog high pass filter deficiencies |
-
2005
- 2005-02-16 KR KR1020050012777A patent/KR20060091970A/en active IP Right Grant
- 2005-10-19 CN CNB200510109204XA patent/CN100361401C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105635453A (en) * | 2015-12-28 | 2016-06-01 | 上海博泰悦臻网络技术服务有限公司 | Conversation volume automatic adjusting method and system, vehicle-mounted device, and automobile |
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| Publication number | Publication date |
|---|---|
| CN100361401C (en) | 2008-01-09 |
| KR20060091970A (en) | 2006-08-22 |
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