Universal automatic frequency control for multi-channel receivers
AssigneeSirius XM Radio Inc.
InventorsCarl Scarpa, Robert Joseph Topper
Life of this patent
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Abstract
Systems and methods for performing automatic frequency control are provided. Instead of relying on individual frequency tuners for each channel of a multi-channel receiver system, the present subject matter uses a single frequency tuner for receiving each channel of the multi-channel receiver system. A locked demodulator may be designated as a reference demodulator and frequency offset values associated with the reference demodulator may be applied to other demodulators of the multi-channel receiver. These frequency offset values may be used by individual demodulators of each channel for correcting corresponding frequency offsets.
Claims20
A data receiver, comprising:
- a tuner for receiving a first signal and a second signal;
- a first demodulator coupled to the tuner, the first demodulator being configured to demodulate the first signal;
- a second demodulator coupled to the tuner, the second demodulator being configured to demodulate the second signal;
- and
- at least one processor coupled to the first and second demodulators, the at least one processor being configured to determine a first frequency offset for the first demodulator,
- wherein, when the second demodulator is unable to lock to the second signal, the at least one processor applies the first frequency offset to the second demodulator.
A method, comprising:
- receiving, by a tuner, a plurality of modulated signals;
- designating, by at least one processor, one of the plurality of modulated signals as a reference signal;
- detecting, by the at least one processor, that a first demodulator is locked onto a first signal of the plurality of modulated signals;
- determining, by the at least one processor, that a frequency drift of the first demodulator satisfies a predetermined threshold drift;
- and
- responsive to the frequency drift satisfying the predetermined threshold drift:
- calculating, by the at least one processor, a frequency offset associated with the reference signal;
- and
- adjusting, by the first demodulator and based on the frequency offset, the first modulated signal to generate a first demodulated signal.
A method, comprising:
- receiving, by a tuner and over a satellite broadcast, a plurality of signals, wherein the plurality of signals are respectively demodulated by a plurality of demodulators;
- designating, by at least one processor, one of the plurality of demodulators as a reference demodulator based on a predefined order;
- determining, by at least one processor, that a first demodulator of the plurality of demodulators is unable to lock to a corresponding first signal of the plurality of signals;
- and
- applying, by the at least one processor, a reference frequency offset associated with the reference demodulator to the first demodulator, wherein the reference frequency offset is based on a frequency offset between a reference signal being received by the reference demodulator and an oscillator.
Dependencies are inferred from the claim text.