Apparatus for Calculating an N-Point Discrete Fourier Transform
AssigneeLSI Corporation
InventorDavid Noeldner
Life of this patent
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Abstract
Described embodiments provide an apparatus for calculating an N-point discrete Fourier transform of an input signal having multiple sample values. The apparatus includes at least one input configured to receive the sample values and a counter to count sample periods. Also included are at least two parallel multipliers to multiply each sample value, with each of the multipliers having a corresponding multiplication factor. There is at least one multiplexer to select one of the at least two parallel multipliers. An adder sums the scaled sample values and an accumulator accumulates the summed sample values. N is an integer and the at least two parallel multipliers are selectable based upon the value of N and the value of the sample period count.
Claims18
An apparatus for calculating an N-point discrete Fourier transform of an input signal having a plurality of sample values, comprising:
- a) at least one input configured to receive sample values;
- b) a counter to count sample periods;
- c) at least two parallel multipliers to multiply each sample value, each of said multipliers having a corresponding multiplication factor;
- d) at least one multiplexer to select one of the at least two parallel multipliers to provide a scaled sample value;
- e) an adder to sum the scaled sample values to provide a summed sample value;
- and
- f) an accumulator to accumulate the summed sample values;
- wherein N is an integer and the at least two parallel multipliers are selectable based upon the value of N and the value of the sample period count.
An apparatus for calculating an N-point discrete Fourier transform having a first input configured to receive an even quadrature sample value and an even phase sample value in a sample period and a second input configured to receive an odd quadrature sample value and an odd phase sample value in a sample period, comprising:
- a) a counter to count the sample periods;
- b) an even sample value scaling circuit;
- c) an odd sample value scaling circuit;
- d) an adder to sum the scaled even and odd quadrature sample values;
- e) an adder to sum the scaled even and odd phase sample values;
- f) an accumulator to accumulate the summed even and odd quadrature sample values;
- and
- g) an accumulator to accumulate the summed even and odd phase sample values;
- wherein N is selectable and is either 3 or 4, the sample value scaling is selectable based upon the value of N and the value of the sample period count, and wherein when N is set to 3, the counter counts 3 sample periods, and wherein when N is set to 4, the counter counts 2 sample periods.
Dependencies are inferred from the claim text.