Method for realizing digital signal processor non-linear function quick and fixed-point operation

A non-linear function and fixed-point calculation technology, which is applied in the field of digital signal processor chips, can solve problems such as monotonous changes in functions, and achieve the effect of meeting computing requirements, small storage space, and high computing speed

Inactive Publication Date: 2007-10-17
CENT ACADEME OF SVA GROUP
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AI Technical Summary

Problems solved by technology

[0005] The mixed method is based on the look-up table and adopts a calculation method to improve the accuracy when the input value is between t

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  • Method for realizing digital signal processor non-linear function quick and fixed-point operation
  • Method for realizing digital signal processor non-linear function quick and fixed-point operation
  • Method for realizing digital signal processor non-linear function quick and fixed-point operation

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Embodiment Construction

[0012] The fast fixed-point implementation method of the nonlinear function of the present invention is used for performing fixed-point calculation on the nonlinear function included in the digital audio-video signal when the digital signal processor encodes the digital audio-video signal, and it is realized through the following specific steps:

[0013] 1) First judge whether the non-linear function f(x) to be calculated is (n+1) order derivable at x=0, n=1, 2,...; if so, proceed to step 2); otherwise end .

[0014] 2) Judging when x is between -π and π (if x is not within this range, use the periodicity of the function to limit x to between -π and π), Whether it is zero, if it is zero, go to step 3), otherwise end;

[0015] 3) Expand the nonlinear function f(x) into McLaughlin's formula, and keep the first n items according to the calculation accuracy:

[0016] f ( x ) ≈ f ( ...

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Abstract

The invention discloses a method for implementing a rapid fixed-point operation of nonlinear function in the digital signal processor. When a digital sound video signal is coded by the digital signal processor, the method carries out the fixed-point calculation for the nonlinear function which is included in the digital sound video signal,firstly the nonlinear function is developped according to Taylor formula, and former n items is reserved to produce the approximate to Maclaurin expansion according to operational precision; then the polynomial in the former step is represented the rapid algorithm form of Qin Jiu Shao polynomial; finally, each item of Qin Jiu Shao polynomial is calibrated using DSP designated implementation method, and takes part in the calculation after calibration. The invention leaves out the switchbetween the fixed-points and floating-point before or after the calculation of nonlinear function, accordingly the operational efficiency is greatly improved; the invention, different with look-up table, reduces the cost of harware without occupying big memory.

Description

technical field [0001] The invention belongs to the field of digital signal processor (DSP, Digital Signal Processor) chips, in particular to a method for realizing fast fixed-point calculation of nonlinear functions in DSP programming. Background technique [0002] In the implementation of audio and video codec algorithms, DSP chips have been increasingly recognized by the industry as a means of computing and processing. In the process of DSP programming, the operation of nonlinear functions is often involved, such as the operation of cosine function cos(), sine function sin() and so on. In normal programming, the most commonly used methods to deal with such functions are: 1. Call the library function of the DSP compilation system; 2. Look-up table method; 3. Mixed method. [0003] It is very convenient to use the method of calling the DSP compiled library function, and the precision of the operation is also very high. But there is a big disadvantage that the input of the...

Claims

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Application Information

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IPC IPC(8): G06F17/15
Inventor 谭建国
Owner CENT ACADEME OF SVA GROUP
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