Device for dft calculation
AssigneeQUALCOMM Incorporated
InventorsAndrea Cenciotti, Nestor Lucas Barriola, Philip John Young
Life of this patent
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Abstract
A device to perform DFT calculations, for example in a GNSS receiver, including two banks of multipliers by constant integer value, the values representing real and imaginary part of twiddle factors in the DFT. A control unit selectively routes the data through the appropriate multipliers to obtain the desired DFT terms. Unused multipliers are tied to constant input values, in order to minimize dynamic power.
Claims13
A device for multiplying a value by a member of a finite set of constant coefficients, comprising a plurality of multipliers wherein each multiplier is specifically arranged to multiply by one of the constant coefficients in said finite set.
The device of the previous claim, including a logic control block, operatively arranged to selectively route said value to the multiplier multiplying by the desired coefficient in said finite set.
The device of the previous claim, wherein said value and said coefficients have complex values.
The device of any of the previous claims, specially arranged to compute a DFT or a DCT or a discrete integral transform.
A device for computing a DFT transform comprising a plurality of multiplier circuits (503), each multiplier circuit being arranged to multiply an input value by a predetermined constant coefficient (C0-C8) corresponding to a real or imaginary part of a twiddle factor of the DFT, including a control logic block (303) operatively arranged to activate a pair of said multipliers corresponding to a twiddle factor of the DFT, and an adder (410), operatively arranged to sum or subtract the outputs of the multipliers of said pair, obtaining the real or the imaginary part of a DFT term.
The device of the previous claim, wherein the multipliers are arranged in two separate banks (403, 406).
The device of the previous claim, wherein a multiplier for a constant coefficient is duplicated in both banks (403, 406).
Method to multiply a value by a member of a finite set of constant coefficients, comprising the steps of:
- providing a plurality of multiplier units, each multiplier unit being specifically arranged to multiply by one of the constant coefficients in said finite set.
- selectively routing said value to the multiplier multiplying by the desired coefficient in said finite set.
The method of the previous claim, wherein said value and said coefficient have complex values.
Dependencies are inferred from the claim text.