Logarithmic converting method and device
A conversion method and conversion device technology, applied in the direction of electrical digital data processing, digital function generators, digital data processing components, etc., can solve the problems of expensive, difficult calculation in floating-point format, and inaccurate calculation of only the first number, etc.
Inactive Publication Date: 2007-10-03
BENQ CORP
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Problems solved by technology
[0003] However, using floating-point format to represent numbers and approximating the result with power series or Newton-Rifson method is very complicated, and consumes time and hardware resources
Moreover, it is difficult and expensive to emulate floating-point format operations in software using fixed-point format hardware.
The look-up table method is to build a pair of numbers first. If a high number of precise digits is required, a huge table will be required and a huge memory space will be occupied.
And only counting the first number is not accurate enough
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[0025] FIG. 1 is a flow chart of an embodiment of the logarithmic conversion method of the present invention. The embodiment of the logarithmic conversion method is used in a digital processing unit for converting a number x to be processed into a logarithm L with a base b as the base. The logarithm L includes an initial number In and a mantissa Ma. The logarithmic transformation method represents all numbers in fixed-point format.
[0026] This embodiment of the logarithmic transformation method includes the following steps. An exact number k of digits required for the mantissa Ma is specified (step 101). A plurality of parameter tables is established by using the base number b, and the number of the plurality of parameter tables is equal to the exact digit k. The mth of the multiple parameter tables is for supply and demand to obtain the value of the mth digit whose mantissa Ma is below the decimal point. Each parameter table can have 10 items. The aforementioned establ...
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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 [0001] The invention relates to a logarithmic conversion method and a device thereof. Background technique [0002] When performing digital signal processing, it is often necessary to convert the number to be processed into logarithm (logarithm). In general, logarithmic transformations are performed in the following ways. One is to represent numbers in floating-point format and approximate the result with a power series or the Newton-Raphson method. In addition, you can also look up the table, or only calculate the initial (integer) part, and ignore the mantissa (mantissa). [0003] However, it is very complicated to use floating-point format to represent numbers and approximate the result by power series or Newton-Rifson method, which consumes time and hardware resources. Moreover, it is difficult and expensive to emulate floating-point format operations in software using fixed-point format hardware. The look-up table method is to build a pair table firs...
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IPC IPC(8): G06F1/03G06F7/556
Inventor 姚锦树
Owner BENQ CORP