Carrier tracking method
AssigneeSymmetricam, Inc.
InventorKishan Shenoi
Life of this patent
Estimating the term…
Abstract
Systems and methods are described for carrier tracking. A center frequency of a signal is tracked by comparing spectral power contents of filtered versions of the signal. A receiver incorporates this carrier tracking. The systems and methods provide advantages because of decreased cost.
Claims42
A method for tracking a center frequency of a signal having substantially equal spectral power content on both sides of the center frequency, said method comprising:
- making an estimate of the center frequency;
- filtering an upper sideband of the signal above the center frequency to produce a first output having a first spectral power content and a lower sideband of the signal below the center frequency to produce a second output having a second spectral power content;
- and
- revising the estimate of the center frequency based on a difference between the first spectral power content and the second spectral power content.
An apparatus for tracking a center frequency of a signal having substantially equal spectral power content on both sides of the center frequency, said apparatus comprising:
- a first filter for producing a first output from an upper sideband of the signal above the center frequency;
- a second filter for producing a second output from a lower sideband of the signal below the center frequency, the second filter matched with the first filter;
- and
- a set of processing resources for making an estimate of the center frequency, calculating the spectral power contents of the first output and the second output, and revising the estimate of the center frequency based on a difference between the spectral power contents of the first output and the second output the set of processing resources being coupled to the first filter and the second filter.
A receiver, comprising:
- an antenna for receiving a signal;
- an oscillator coupled to the antenna, the oscillator making an estimate of a carrier frequency of the signal;
- first processing resources for digitizing the signal, the first processing resources coupled to the antenna;
- a first filter for producing a first output from an upper sideband of the signal above the estimate of the carrier frequency, the first filter coupled to the first processing resources;
- a second filter for producing a second output from a lower sideband of the signal below the estimate of the center frequency, the second filter matched with the first filter such that the second filter is symmetrical with the first filter about the estimate of the carrier frequency, and the second filter coupled to the first processing resources;
- and
- second processing resources for generating an error estimate of the estimate of the carrier frequency, and the second processing resources coupled to the oscillator.
An apparatus for tracking a center frequency of a signal having substantially equal spectral power content on both sides of the center frequency, the apparatus comprising:
- a first filter means for producing a first output from an upper sideband of the signal above the center frequency;
- a second filter means for producing a second output from a lower sideband of the signal below the center frequency, the second filter matched with the first filter;
- and
- processing means for making an estimate of the center frequency, calculating the spectral power contents of the first output and the second output, and revising the estimate of the center frequency based on the spectral power contents of the first output and the second output, said processing means coupled to both the first filter means and the second filter means.
Dependencies are inferred from the claim text.