Low-power oscillator
AssigneeQUALCOMM Incorporated
InventorsDaniel Filipovic, Hongbo Yan
Life of this patent
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Abstract
Techniques for synthesizing a signal having a desired frequency from an oscillation signal. In an aspect, a reference signal having a known frequency may be periodically used to determine a ratio between the desired frequency and the frequency of the oscillation signal. The oscillation signal may be decimated by the ratio to generate a synthesized signal having approximately the desired frequency. In an aspect, the decimation may be performed by generating a pulse in response to the output of an accumulator that accumulates in steps of the ratio. To save power, the oscillation signal may be derived from a low-power oscillator, while the reference signal may be turned on only during periodic calibration. Further aspects for improving the frequency accuracy of the synthesized signal are disclosed.
Claims38
A method for synthesizing a signal having a desired frequency from an oscillation signal, the method comprising:
- computing a ratio between the desired frequency and the frequency of the oscillation signal using a reference signal, the reference signal having a known frequency, the frequency of the oscillation signal being greater than the desired frequency;
- and
- decimating the oscillation signal according to the computed ratio to generate the synthesized signal, the decimating the oscillation signal comprising:
- at each cycle of the oscillation signal, incrementing a counter;
- generating a pulse when the counter value is equal to or greater than 1;
- and
- decrementing the counter value by 1 when the counter value is equal to or greater than 1.
An apparatus for synthesizing a signal having a desired frequency from an oscillation signal, the apparatus comprising:
- a ratio calculator for computing a ratio between the desired frequency and the frequency of the oscillation signal using a reference signal, the reference signal having a known frequency, the frequency of the oscillation signal being greater than the desired frequency;
- and
- a decimator for decimating the oscillation signal according to the computed ratio to generate the synthesized signal;
- the decimator operative to:
- increment a counter at each cycle of the oscillation signal;
- generate a pulse when the counter value is equal to or greater than 1;
- and
- decrement the counter value by 1 when the counter value is equal to or greater than 1.
An apparatus for synthesizing a signal having a desired frequency from an oscillation signal, the apparatus comprising:
- means for computing a ratio between the desired frequency and the frequency of the oscillation signal;
- and
- means for decimating the oscillation signal according to the computed ratio to generate the synthesized signal, the means for decimating the oscillation signal comprising:
- at each of the oscillation signal, incrementing a counter;
- generating a pulse when the counter value is equal to or greater than 1;
- and
- decrementing the counter value by 1 when the counter value is equal to or greater than 1.
A non-transitory computer program product storing code for causing a computer to synthesize a signal having a desired frequency from an oscillation signal, the code comprising:
- code for causing a computer to compute a ratio between the desired frequency and the frequency of the oscillation signal using a reference signal, the reference signal having a known frequency, the frequency of the oscillation signal being greater than the desired frequency;
- and
- code for causing a computer to decimate the oscillation signal according to the computed ratio to generate the synthesized signal, the code for causing the computer to decimate the oscillation signal comprising:
- code for incrementing a counter at each cycle of the oscillation signal;
- code for generating a pulse when the counter value is equal to or greater than 1;
- and
- code for decrementing the counter value by 1 when the counter value is equal to or greater than 1.
Dependencies are inferred from the claim text.