Electrical computers: arithmetic processing and calculating – Electrical digital calculating computer – Particular function performed
Reexamination Certificate
2003-02-25
2008-10-21
Ngo, Chuong D (Department: 2193)
Electrical computers: arithmetic processing and calculating
Electrical digital calculating computer
Particular function performed
C708S440000
Reexamination Certificate
active
07440987
ABSTRACT:
A direct digital synthesizer employs a trigonometric function generator utilizing decomposition of a larger angle into smaller sub-angles, interpolation of a desired sub-angle between two known angles and calculating the trigonometric function using complex arithmetic. The direct digital synthesizer has a phase accumulator to generate an angular increment signal of the output signal. A trigonometric function generator in communication with the phase accumulator receives the angle signal and from the angle signal creates the trigonometric function signal. An angle decomposing circuit is connected to receive the angle signal to separate the angle signal into sub-angles of the angular increment, a sum of the sub-angles equaling the angular increment. An interpolation circuit receives the smallest of the sub-angles to generate the trigonometric function for the smallest of the sub-angles by interpolating between the trigonometric function of two known angles. The direct digital synthesizer has a first angle trigonometric retaining for retaining the trigonometric functions of the known angles. At least one second angle trigonometric retaining circuit retains the trigonometric functions of for the remaining sub-angles. A complex arithmetic unit combines the interpolated trigonometric function and the second trigonometric function from each of the second angle trigonometric retaining circuits to create the trigonometric function.
REFERENCES:
patent: 4718030 (1988-01-01), Tsutsumi
patent: 4893316 (1990-01-01), Janc et al.
patent: 5737253 (1998-04-01), Madisetti et al.
patent: 5986483 (1999-11-01), Yu et al.
patent: 5999581 (1999-12-01), Bellaouar et al.
patent: 6640237 (2003-10-01), Genrich
A Technical Tutorial on Digital Signal Synthesis, Analog Devices Inc., Norwood, MA, Copyright 1999, pp. 5-9.
“A 150-MHz Direct Digital Frequency Synthesizer in 1.25um, CMOS with -90-dBc Spurious Performance,” Nicholas, et al., IEEE Journal of Solid-State Circuits, Dec. 1991, vol. 26, No. 12, pp. 1959-1969.
“A 100-MHz, 16-b, Direct Digital Frequency Synthesizer with a 100-dBc Spurious-Free Dynamic Range,” Madisetti, et al., IEEE Jrnl. of Solid-State Circuits, Aug. 1999, vol. 34, No. 8, pp. 1034-1043.
“Low-Power Direct Digital Frequency Synthesis for Wireless Communications,” Bellaouar, et al., IEEE Jrnl. of Solid-State Circuits, Mar. 2000, vol. 35, No. 3, pp. 385-390.
Kim Beomsup
Song Yongchul
Ngo Chuong D
QUALCOMM Incorporated
Rouse Thomas R.
Velasco Jonathan T.
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