CN1677308A - Logarithmic converting method and device - Google Patents
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- CN1677308A CN1677308A CN 200410033338 CN200410033338A CN1677308A CN 1677308 A CN1677308 A CN 1677308A CN 200410033338 CN200410033338 CN 200410033338 CN 200410033338 A CN200410033338 A CN 200410033338A CN 1677308 A CN1677308 A CN 1677308A
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Abstract
The invention provides a logarithmic converting method for a digital processing unit, converting a number X to be processed into a base number b-based logarithm L containing a leading number ln and a mantissa Ma, expressing all the numbers in a fixed-point format and containing the following steps: assigning an accurate bit number k for the Ma; using the base number b to establish many parameter tables, where the number of them equal to the bit number k, and the table m is for obtaining the value of the bit m behind the decimal point of the Ma; calculating the number ln; and in turn looking up many parameter tables to obtain the values of the bits from 1 to k behind the Ma.
Description
Technical field
The present invention relates to a kind of logarithm conversion method and device thereof.
Background technology
Carry out digital signal processing and pending number must be transferred to logarithm (logarithm) often.General execution has following method to number conversion.One is with floating-point (floating-point) form shfft registration word, and with power series (power series) or newton-Rui Fu think of a way (Newton-Raphson method) approach the result.Also can table look-up in addition, or only calculate first number (integer) part, and ignore mantissa (mantissa).
So utilize floating-point format to represent numeral, and very complicated in the think of a way mode of approaching the result of power series or newton-Rui Fu, and expend time in and hardware resource.And use the hardware of fixed point format expensive with software emulation floating-point format computing also difficulty.Look-up table is to build up a table of logarithm earlier, if require accurate figure place height, and then must huge form and take huge memory headroom.And it is accurate inadequately only to calculate first number.Therefore need a kind of enough accurate simply again logarithm conversion method and device.
Summary of the invention
Fundamental purpose of the present invention is providing a kind of enough accurate simply again logarithm conversion method and device.The present invention looks the required accurate figure place of mantissa and sets up and the identical parameter list of required accurate figure place number, and m table can be used for asking for the m position of mantissa below radix point.The present invention is simple because of being that lookup table mode utilizes floating-point format to represent that numeral is approached result's mode again.The number of parameter list is decided according to required accurate figure place, and can be as the meaningless memory headroom that expends of lookup table mode.It is accurate to specify in addition accurate figure place also more only to calculate the mode of first number according to need.
The invention provides a kind of logarithm conversion method that is used for a digital processing element.It is a logarithm L at the end that this logarithm conversion method system is converted to pending several x with a truth of a matter b, and logarithm L comprises a first number In and a Ma of mantissa.The logarithm conversion method is represented all numerals with fixed point format.The logarithm conversion method comprises the following step.An accurate figure place k who specifies the Ma of mantissa to require.Utilize truth of a matter b to set up a plurality of parameter lists, the number of a plurality of parameter lists equals accurate figure place k.The m of a plurality of parameter lists is the value that supply and demand are got the m position of the Ma of mantissa below radix point.Calculate first number In.And search a plurality of parameter lists in regular turn, to get the value of the Ma of mantissa the 1st to k position below radix point.
Aforementioned calculation procedure can comprise following steps.Seek the y power that a digital y makes truth of a matter b and be not more than pending several x, and (y+1) power of truth of a matter b is greater than pending several x.And export number In headed by the digital y.
Aforementioned each parameter list can have 10 projects.Aforementioned establishment step can comprise the following step.Be the individual coefficient S C that determines of the m of a plurality of parameter lists
mAnd the n power of truth of a matter b opened 10
mThe power radical sign multiply by coefficient S C again
m, as m n project of a plurality of parameter lists, n=0 ..., 9.Coefficient S C wherein
mSystem is for the spacing that widens 10 projects.Coefficient S C
mCan be 2 power series (power series).
Aforementioned finding step can comprise the following step.Set m and equal 1.If m=1 removes among pending several x, the part that first number In constitutes multiply by coefficient S C again
mTo get a temporary transient number Temp.Otherwise remove among pending several x, first number In and the Ma of mantissa the 1st part that constitutes to (m-1) position below radix point multiply by coefficient S C again
mTemporarily count Temp to get.Seek m n project Tab of a plurality of parameter lists
m[n] makes Tab
m[n] is not more than temporary transient several Temp, and Tab
m[n+1] is greater than temporary transient number Temp.Output n is the m position of the Ma of mantissa below radix point.M is added 1.Relatively m and accurately figure place k.And if m is not more than accurate figure place k, double counting is temporarily counted Temp to relatively m and the accurately step of figure place k.
It is a kind of to analog-to-digital conversion apparatus that the present invention also provides, and is a logarithm L at the end for pending several x are converted to a truth of a matter b.Logarithm L comprises a first number In and a Ma of mantissa.Analog-to-digital conversion apparatus is represented all numerals with fixed point format.Analog-to-digital conversion apparatus is comprised a specified device, an apparatus for establishing, a calculation element and search device.Specified device is for an accurate figure place k who specifies the Ma of mantissa to require.Apparatus for establishing is for utilizing truth of a matter b to set up a plurality of parameter lists.The number of a plurality of parameter lists equals accurate figure place k.The m of a plurality of parameter lists is that supply and demand are got the m position of the Ma of mantissa below radix point.Calculation element is for calculating first number In.Search device for searching a plurality of parameter lists in regular turn, to get 1st to the k position of the Ma of mantissa below radix point.
Aforementioned calculation element can comprise one first and seek unit and one first output unit.First seeks the unit makes the y power of truth of a matter b be not more than pending several x for seeking a digital y, and (y+1) power of truth of a matter b is greater than pending several x.First output unit is counted In headed by the digital y of output.
Aforementioned each parameter list can have 10 projects.Aforementioned apparatus for establishing can comprise a decision unit and one first arithmetic element.The decision unit is for being the individual coefficient S C that determines of the m of a plurality of parameter lists
mFirst arithmetic element is for the n power of truth of a matter b is opened 10
mThe power radical sign multiply by coefficient S C again
m, as m n project of a plurality of parameter lists, n=0 ..., 9.Coefficient S C wherein
mBe for the spacing that widens 10 projects.Coefficient S C
mCan be 2 power series.
The aforementioned device of searching can comprise a setup unit, one second arithmetic element, one second searching unit, one second output unit, an adder unit, a comparing unit and a logical block.Setup unit equals 1 for setting m.If m=1, second arithmetic element is for removing among pending several x, and the part that first number In constitutes multiply by coefficient S C again
mTo get a temporary transient number Temp.Otherwise second arithmetic element is for removing among pending several x, and first number In and the Ma of mantissa the 1st part that constitutes to (m-1) position below radix point multiply by coefficient S C again
mTemporarily count Temp to get.Second seeks the unit for n individual project Tab of the m that seeks a plurality of parameter lists
m[n] makes Tab
m[n] is not more than temporary transient several Temp, and Tab
m[n+1] is greater than temporary transient number Temp.Second output unit is the m position of the Ma of mantissa below radix point for output n.Adder unit is for m is added 1.Comparing unit is for relatively m and accurately figure place k.If m is not more than accurate figure place k, logical block is sought unit, second output unit, adder unit and comparing unit for indication second arithmetic element, second and is repeated pairing action in regular turn.
The accompanying drawing summary
Fig. 1 is the process flow diagram of logarithm conversion method one embodiment of the present invention;
Fig. 2 is that the present invention is to analog-to-digital conversion apparatus one embodiment calcspar; And
Fig. 3 is parameter list one embodiment of the present invention.
The reference numeral explanation
200 pairs of analog-to-digital conversion apparatus embodiment 202 specified devices
204 apparatus for establishing, 206 decision unit
208 first arithmetic elements, 210 calculation elements
212 first seek unit 214 first output units
216 search device 218 setup units
220 second arithmetic elements 222 second are sought the unit
224 second output units, 226 adder units
228 comparing units, 230 logical blocks
Embodiment
Fig. 1 is the process flow diagram of logarithm conversion method one embodiment of the present invention.This logarithm conversion method embodiment is used for a digital processing element, is a logarithm L at the end for pending several x are converted to a truth of a matter b.Logarithm L comprises a first number In and a Ma of mantissa.The logarithm conversion method is represented all numerals with fixed point format.
This logarithm conversion method embodiment comprises the following step.An accurate figure place k (step 101) who specifies the Ma of mantissa to require.Utilize truth of a matter b to set up a plurality of parameter lists, the number of a plurality of parameter lists equals accurate figure place k.The m of a plurality of parameter lists is the value that supply and demand are got the m position of the Ma of mantissa below radix point.Each parameter list can have 10 projects.Aforementioned establishment step can comprise the following step.Be the individual coefficient S C that determines of the m of a plurality of parameter lists
m(step 103).The coefficient of each parameter list can be different.Coefficient S C
mBe for widening the spacing of 10 projects, if spacing is enough, but also SC
m=1.Coefficient S C
mCan be 2 power series, the computing in the time of so can making things convenient for numeral to represent with 2 carries.Then the n power of truth of a matter b is opened 10
mThe power radical sign multiply by coefficient S C again
m, as m n project of a plurality of parameter lists, n=0 ..., 9 (steps 105).
Other calculates first number In.This calculation procedure can comprise following steps.Seek the y power that a digital y makes truth of a matter b and be not more than pending several x, and (y+1) power of truth of a matter b is greater than pending several x (step 107).And export number In (step 109) headed by the digital y.
Then search a plurality of parameter lists in regular turn, to get the value of the Ma of mantissa the 1st to k position below radix point.This finding step can comprise the following step.Set m and equal 1 (step 111).If m=1 removes among pending several x, the part that first number In constitutes multiply by coefficient S C again
mTo get a temporary transient number Temp.Otherwise remove among pending several x, first number In and the Ma of mantissa the 1st part that constitutes to (m-1) position below radix point multiply by coefficient S C again
mTemporarily count Temp (step 113) to get.Seek m n project Tab of a plurality of parameter lists
m[n] makes Tab
m[n] is not more than temporary transient several Temp, and Tab
m[n+1] is greater than temporary transient number Temp (step 115).Output n is the m position (step 117) of the Ma of mantissa below radix point.M is added 1 (step 119).Relatively m and accurately figure place k (step 121).If m is not more than accurate figure place k, double counting is temporarily counted Temp to relatively m and the accurately step (step 113-121) of figure place k.If m is greater than k, then exportable before the figure place (step 123) that below radix point, requires of the Ma of gained mantissa.Aforementioned searching Tab
mThe step (step 115) of [n] can have many modes, for example begins the comparison size by the 0th project, or begins the comparison size by the 4th or the 5th project.
Though aforementioned establishment step (step 103-105) is prior to calculation procedure (step 107-109), but so also calculation procedure (step 107-109) is prior to establishment step (step 103-105), or both carry out simultaneously.
Fig. 2 is the calcspar of the present invention to analog-to-digital conversion apparatus one embodiment 200.Is a logarithm L at the end to analog-to-digital conversion apparatus embodiment 200 for pending several x are converted to a truth of a matter b.Logarithm L comprises a first number In and a Ma of mantissa.This embodiment 200 represents all numerals with fixed point format.This embodiment 200 comprises a specified device 202, an apparatus for establishing 204, a calculation element 210 and and searches device 216.
Specified device 202 is for an accurate figure place k who specifies the Ma of mantissa to require.Apparatus for establishing 204 is for utilizing truth of a matter b to set up a plurality of parameter lists.The number of a plurality of parameter lists equals accurate figure place k.The m of a plurality of parameter lists is that supply and demand are got the m position of the Ma of mantissa below radix point.Aforementioned each parameter list can have 10 projects.Apparatus for establishing 204 comprises a decision unit 206 and one first arithmetic element 208.Decision unit 206 is for being the individual coefficient S C that determines of the m of a plurality of parameter lists
mThe coefficient of each parameter list can be different.Coefficient S C
mBe for widening the spacing of 10 projects, if spacing is enough, but also SC
m=1.Coefficient S C
mCan be 2 power series, the computing in the time of so can making things convenient for numeral to represent with 2 carries.First arithmetic element 208 is for the n power of truth of a matter b is opened 10
mThe power radical sign multiply by coefficient S C again
m, as m n project of a plurality of parameter lists, n=0 ..., 9.
Calculation element 210 is for calculating first number In.Calculation element 210 can comprise one first and seek unit 212 and one first output unit 214.First seeks unit 212 makes the y power of truth of a matter b be not more than pending several x for seeking a digital y, and (y+1) power of truth of a matter b is greater than pending several x.First output unit 214 is counted In headed by the digital y of output.
Search device 216 for searching a plurality of parameter lists in regular turn, to get 1st to the k position of the Ma of mantissa below radix point.Search device 216 and can comprise a setup unit 218, one second arithmetic element 220, one second searching unit 222, one second output unit 224, an adder unit 226, a comparing unit 228 and a logical block 230.Setup unit 218 equals 1 for setting m.If m=1, second arithmetic element 220 is for removing among pending several x, and the part that first number In constitutes multiply by coefficient S C again
mTo get a temporary transient number Temp.Otherwise second arithmetic element 220 is for removing among pending several x, and first number In and the Ma of mantissa the 1st part that constitutes to (m-1) position below radix point multiply by coefficient S C again
mTemporarily count Temp to get.Second seeks unit 222 for n individual project Tab of the m that seeks a plurality of parameter lists
m[n] makes Tab
m[n] is not more than temporary transient several Temp, and Tab
m[n+1] is greater than temporary transient number Temp.Second output unit 224 is the m position of the Ma of mantissa below radix point for output n.Adder unit 226 is for m is added 1.Comparing unit 228 is for relatively m and accurately figure place k.If m is not more than accurate figure place k, logical block 230 is sought unit 222, second output unit 224, adder unit 226 and comparing unit 228 for indication second arithmetic element 220, second and is repeated pairing action in regular turn.Aforementioned second seeks unit 222 seeks Tab
m[n] can have many modes, for example begins the comparison size by the 0th project, or begins the comparison size by the 4th or the 5th project.
Below illustrate the running of logarithm conversion method of the present invention and device.Suppose that pending several x equal 135, truth of a matter b equals 10.The accurate figure place k that at first specifies the Ma of mantissa to require equals 3.Next can set up parameter list simultaneously and calculate first number In, or set up parameter list earlier and calculate first number In again, otherwise or.Hypothesis is set up parameter list earlier herein.Please refer to Fig. 3, Fig. 3 is a parameter list embodiment.Owing to require accurate figure place k to equal 3, so set up 3 parameter lists.The 1st parameter list supply and demand are got the Ma of mantissa below radix point the 1st, and the rest may be inferred by analogy.Each parameter list all has 10 projects.Coefficient S C for these 3 parameter list decisions
1-SC
3All be 4096.0 power of the truth of a matter 10 is opened 10
1Radical sign is taken advantage of SC again
1, promptly 10
0.0* 4096, as the 0th project Tab of the 1st parameter list
1[0]; 1 power of the truth of a matter 10 is opened 10
1Radical sign is taken advantage of SC again
1, promptly 10
0.1* 4096, as the 1st project Tab of the 1st parameter list
1[1], the rest may be inferred by analogy.
Then calculate first number In.We can find a digital y to equal 2, make the y power of truth of a matter b (=10) be not more than pending several x (=135), and (y+1) power of truth of a matter b is greater than pending several x, and promptly 10
2≤ 135＜10
(2+1), then first number In equals 2.
Then search parameter list to ask for the Ma of mantissa.
* set m=1
* m=1 then removes among the x (=135), and the part that In (=2) constitutes multiply by SC again
1(=4096) are to get Temp; Temp=135 * 4096/10 then
2=5529.6
* search Tab
1, find n=1 to make Tab
1[1]≤Temp＜Tab
1[2], promptly 5157≤5529.6＜6492
* exporting n (=1) is Ma[1], i.e. Ma[1]=1
* with m+1, i.e. m=2
* compare m (=2) and k (=3)
* m≤k, promptly 2≤3, then repeat to ask for Temp to the relatively action of m and k
* m=2 then removes among the x (=135) In (=2) and Ma[1] part that (=1) constitutes, multiply by SC again
2(=4096) are to get Temp; Temp=135 * 4096/10 then
2.1 4392
* search Tab
2, find n=3 to make Tab
2[3]≤Temp＜Tab
2[4], promptly 4389≤4392＜4491
* exporting n (=3) is Ma[2], i.e. Ma[2]=3
* with m+1, i.e. m=3
* compare m (=3) and k (=3)
* m≤k, promptly 3≤3, then repeat to ask for Temp to the relatively action of m and k
* m=3 then removes among the x (=135) In (=2), Ma[1] (=1) and Ma[2] part that (=3) constitute, multiply by SC again
3(=4096) are to get Temp; Temp=135 * 4096/10 then
2.13 4099
* search Tab
3, find n=0 to make Tab
3[0]≤Temp＜Tab
3[1], promptly 4096≤4099＜4105
* exporting n (=0) is Ma[3], i.e. Ma[3]=0
* with m+1, i.e. m=4
* compare m (=4) and k (=3)
* m＞k, promptly 4＞3, tenth skill then, the Ma=0.130 of mantissa
Then obtaining first number In at last is 2, and the Ma of mantissa is 0.130, and then logarithm L is 2.130, i.e. log
10X=log
10135 2.130.
Above-mentioned explanation is not the restriction to category of the present invention, and the arrangement of above-mentioned explanation and various change and isotropism is all in the category that the present patent application claim is intended to protect.
Claims (12)
1. logarithm conversion method that is used for a digital processing element, be that pending several x are converted to a truth of a matter b is a logarithm L at the end, this logarithm L comprises a first number In and a Ma of mantissa, and this logarithm conversion method is represented all numerals with fixed point format, and this logarithm conversion method comprises the following step:
An accurate figure place k who specifies the Ma of this mantissa to require;
Utilize this truth of a matter b to set up a plurality of parameter lists, the number of these a plurality of parameter lists equals this accurate figure place k, and the m of these a plurality of parameter lists is the value that supply and demand are got this mantissa m position of Ma below radix point;
Calculate this head and count In; And
Search this a plurality of parameter lists in regular turn, with value that must this mantissa Ma the 1st to k position below radix point.
2. logarithm conversion method as claimed in claim 1, wherein, this calculation procedure comprises:
Seek the y power that a digital y makes this truth of a matter b and be not more than this pending several x, and (y+1) power of this truth of a matter b is greater than these pending several x; And
Export this numeral y and count In for this head.
3. logarithm conversion method as claimed in claim 1, wherein, each this parameter list has 10 projects, and this establishment step comprises:
Be the individual coefficient S C that determines of the m of these a plurality of parameter lists
mAnd
The n power of this truth of a matter b is opened 10
mThe power radical sign multiply by this coefficient S C again
m, as m n project of these a plurality of parameter lists, n=0 ..., 9;
Wherein, this coefficient S C
mBe for the spacing that widens these 10 projects.
4. logarithm conversion method as claimed in claim 3, wherein, this coefficient S C
mBe 2 power series.
5. logarithm conversion method as claimed in claim 3, wherein, this finding step comprises:
Remove among these pending several x, this head counts In and 1st part that to (m-1) position constitute of the Ma of this mantissa below radix point, multiply by this coefficient S C again
mTo get a temporary transient number Temp;
Seek m n project Tab of these a plurality of parameter lists
m[n] makes Tab
m[n] is not more than this temporary transient number Temp, and Tab
m[n+1] is greater than this temporary transient number Temp; And
Output n is this mantissa m position of Ma below radix point.
6. logarithm conversion method as claimed in claim 3, wherein, this finding step comprises:
(a) set m and equal 1;
(b) if m=1 removes among these pending several x, this head counts the part that In constitutes, and multiply by this coefficient S C again
mTo get a temporary transient number Temp; Otherwise remove among these pending several x, this head counts In and 1st part that to (m-1) position constitute of the Ma of this mantissa below radix point, multiply by this coefficient S C again
mMust be somebody's turn to do temporary transient number Temp;
(c) seek n the project Tab of the m of these a plurality of parameter lists
m[n] makes Tab
m[n] is not more than this temporary transient number Temp, and Tab
m[n+1] is greater than this temporary transient number Temp;
(d) output n is this mantissa m position of Ma below radix point;
(e) m is added 1;
(f) compare m and this accurate figure place k; And
(g) if m is not more than this accurate figure place k, repeat this step (b) to (f).
7. one kind to analog-to-digital conversion apparatus, is a logarithm L at the end for pending several x are converted to a truth of a matter b, and this logarithm L comprises a first number In and a Ma of mantissa, and this represents all numerals to analog-to-digital conversion apparatus with fixed point format, and this comprises analog-to-digital conversion apparatus:
One specified device is for an accurate figure place k who specifies the Ma of this mantissa to require;
One apparatus for establishing, for utilizing this truth of a matter b to set up a plurality of parameter lists, the number of these a plurality of parameter lists equals this accurate figure place k, and the m of these a plurality of parameter lists is that supply and demand are got this mantissa m position of Ma below radix point;
One calculation element is counted In for calculating this head; And
One searches device, for searching this a plurality of parameter lists in regular turn, with must 1st to the k position of the Ma of this mantissa below radix point.
8. as claimed in claim 7 to analog-to-digital conversion apparatus, wherein, this calculation element comprises:
One first seeks the unit, make the y power of this truth of a matter b be not more than this pending several x for seeking a digital y, and (y+1) power of this truth of a matter b is greater than these pending several x; And
One first output unit, y is that this head counts In for this numeral of output.
9. as claimed in claim 7 to analog-to-digital conversion apparatus, wherein, each this parameter list has 10 projects, and this apparatus for establishing comprises:
One decision unit is for being the individual coefficient S C that determines of the m of these a plurality of parameter lists
mAnd
One first arithmetic element is for the n power of this truth of a matter b is opened 10
mThe power radical sign multiply by this coefficient S C again
m, as m n project of these a plurality of parameter lists, n=0 ..., 9;
Wherein, this coefficient S C
mBe for the spacing that widens these 10 projects.
10. as described in claim 9, be to analog-to-digital conversion apparatus, wherein, this coefficient S C
mBe 2 power series.
11. as claimed in claim 9 to analog-to-digital conversion apparatus, wherein, this is searched device and comprises:
One second arithmetic element, for removing among these pending several x, this head counts In and 1st part that to (m-1) position constitute of the Ma of this mantissa below radix point, multiply by this coefficient S C again
mTo get a temporary transient number Temp;
One second seeks the unit, for the m that seeks these a plurality of parameter lists n project Tab
m[n] makes Tab
m[n] is not more than this temporary transient number Temp, and Tab
m[n+1] is greater than this temporary transient number Temp; And
One second output unit, n is this mantissa m position of Ma below radix point for output.
12. as claimed in claim 9 to analog-to-digital conversion apparatus, wherein, this is searched device and comprises:
One setup unit equals 1 for setting m;
One second arithmetic element, if m=1, this second arithmetic element is for removing among these pending several x, this head counts the part that In constitutes, and multiply by this coefficient S C again
mTo get a temporary transient number Temp; Otherwise this second arithmetic element is for removing among these pending several x, and this head counts In and 1st part that to (m-1) position constitute of the Ma of this mantissa below radix point, multiply by this coefficient S C again
mMust be somebody's turn to do temporary transient number Temp;
One second seeks the unit, for the m that seeks these a plurality of parameter lists n project Tab
m[n] makes Tab
m[n] is not more than this temporary transient number Temp, and Tab
m[n+1] is greater than this temporary transient number Temp;
One second output unit, n is this mantissa m position of Ma below radix point for output;
One adder unit is for m is added 1;
One comparing unit is for comparing m and this accurate figure place k; And
One logical block, if m is not more than this accurate figure place k, this logical block repeats pairing action in regular turn for this second arithmetic element of indication, this second searching unit, this second output unit, this adder unit and this comparing unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100333383A CN100340940C (en) | 2004-04-02 | 2004-04-02 | Logarithmic converting method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100333383A CN100340940C (en) | 2004-04-02 | 2004-04-02 | Logarithmic converting method and device |
Publications (2)
| Publication Number | Publication Date |
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| CN1677308A true CN1677308A (en) | 2005-10-05 |
| CN100340940C CN100340940C (en) | 2007-10-03 |
Family
ID=35049851
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100333383A Expired - Fee Related CN100340940C (en) | 2004-04-02 | 2004-04-02 | Logarithmic converting method and device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102436365A (en) * | 2010-12-20 | 2012-05-02 | 中国电子科技集团公司第四十一研究所 | Method and device for transforming high-speed linear spectrum data to logarithm data |
| CN103455302A (en) * | 2012-05-31 | 2013-12-18 | 上海华虹集成电路有限责任公司 | Circuit for realizing logarithm operation by using hardware |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4626825A (en) * | 1985-07-02 | 1986-12-02 | Vlsi Technology, Inc. | Logarithmic conversion apparatus |
| SE470542B (en) * | 1992-12-07 | 1994-07-25 | Foersvarets Forskningsanstalt | Device for converting a binary floating point into a 2 logarithm in binary form or vice versa |
| US5604691A (en) * | 1995-01-31 | 1997-02-18 | Motorola, Inc. | Logarithm/inverse-logarithm converter utilizing a truncated Taylor series and method of use thereof |
| US5703801A (en) * | 1995-01-31 | 1997-12-30 | Motorola, Inc. | Logarithm/inverse-logarithm converter utilizing second-order term and method of using same |
| JP3110288B2 (en) * | 1995-07-21 | 2000-11-20 | 日本電気株式会社 | Exponential logarithmic conversion circuit |
| US6182100B1 (en) * | 1998-06-30 | 2001-01-30 | International Business Machines Corporation | Method and system for performing a logarithmic estimation within a data processing system |
-
2004
- 2004-04-02 CN CNB2004100333383A patent/CN100340940C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102436365A (en) * | 2010-12-20 | 2012-05-02 | 中国电子科技集团公司第四十一研究所 | Method and device for transforming high-speed linear spectrum data to logarithm data |
| CN102436365B (en) * | 2010-12-20 | 2014-04-09 | 中国电子科技集团公司第四十一研究所 | Method and device for transforming high-speed linear spectrum data to logarithm data |
| CN103455302A (en) * | 2012-05-31 | 2013-12-18 | 上海华虹集成电路有限责任公司 | Circuit for realizing logarithm operation by using hardware |
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| Publication number | Publication date |
|---|---|
| CN100340940C (en) | 2007-10-03 |
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