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US 5,673,212 AGranted
Method and apparatus for numerically controlled oscillator with partitioned phase accumulator
AssigneeMotorola, Inc.
InventorRobert Karl Hansen
Life of this patent
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AssigneeMotorola, Inc.
InventorRobert Karl Hansen
Estimating the term…
A numerically controlled oscillator (NCO) (10) or direct digital synthesizer (DSS) includes a phase accumulator (12, 28, 30), a phase to amplitude converter (24), and a digital to analog converter (26). The phase accumulator is partitioned into a high speed phase accumulator stage (44) and a low speed phase accumulator stage (46). The high speed stage (44) performs modulo accumulation on the most significant N.sub.M bits of the entire phase word. The low speed stage (46) performs modulo accumulation on the least significant N.sub.L bits of the entire phase word. The low speed stage (46) supplies a carry signal to the high speed stage (44). The low speed stage (46) operates with an accumulation period that is 2.sup.X times slower than the accumulation period for the high speed stage (44). A phase output is taken from the most significant N.sub.p of the N.sub.M bits accumulated in the high speed stage (44), where desirably N.sub.M .gtoreq.N.sub.p +X.
A numerically controlled oscillator (NCO) for generating an oscillation signal having a frequency determined in response to a frequency word having more significant bits and having less significant bits, said NCO comprising:
A method for tracking phase in a numerically controlled oscillator (NCO), said phase being tracked in response to a frequency word having more significant bits and having less significant bits, and said method comprising the steps of:
A numerically controlled oscillator (NCO) for generating an oscillation signal having a frequency determined in response to a frequency word having more significant bits and having less significant bits, said NCO comprising:
Dependencies are inferred from the claim text.