Electrical computers: arithmetic processing and calculating – Electrical digital calculating computer – Particular function performed
Reexamination Certificate
2005-07-22
2009-08-18
Malzahn, David H (Department: 2193)
Electrical computers: arithmetic processing and calculating
Electrical digital calculating computer
Particular function performed
Reexamination Certificate
active
07577695
ABSTRACT:
A direct digital synthesis (DDS) circuit utilizes high order delta-sigma interpolators to remove frequency, phase and amplitude domain quantization errors. The DDS employs an n-bit accumulator operative for receiving an input frequency word (FCW) representing the desired frequency output and converts the frequency word to phase information based upon the clock frequency of the DDS. A high-order delta-sigma interpolator is configured in frequency, phase or amplitude domain to noise-shape the quantization errors through a unit defined by the transfer function of 1-(1−z−1)kin either a feedforward or feedback manner. The delta-sigma interpolator of any order can be implemented using a single-stage pipelined topology with noise transfer function of (1−z−1)k. The DDS circuit also includes digital-to-analog converters (DACs) that convert the outputted sine and cosine amplitude words to analog sinusoidal quardrature signals; and deglitch analog low-pass filters that remove the small glitches due to data conversion.
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Andrus Sceales Starke & Sawall LLP
Auburn University
Malzahn David H
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