Method and apparatus for a programmable filter
OwnerDerek K. Shaefferinventor
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Abstract
A system includes a sampling circuit, an analog filter, an analog input, a modulator, and a modulating source. The modulating source includes an output that generates an impulse response encoded as a sigma-delta sequence. The output of the modulating source is coupled to the modulator, which is coupled to the analog input. The analog filter is coupled to the modulator and the sampling circuit. When the system is configured as a filter, an analog signal is modulated with the sigma-delta sequence. The modulated signal is filtered and then sampled.
Claims66
A method of filtering an analog signal comprising:
- encoding an impulse response into a one-bit sigma-delta sequence;
- modulating the analog signal with the sigma-delta sequence;
- filtering the modulated analog signal;
- and
- sampling the filtered signal.
An analog filter comprising:
- a commutating modulator comprising a first input configured to receive an impulse response encoded as a sigma-delta sequence and a second input configured to receive an analog signal;
- a filter coupled to an output of the commutating modulator;
- and
- a sampling circuit coupled to an output of the filter.
A filter comprising:
- an analog input configured to receive analog signals;
- a modulating source comprising an output that generates an impulse response encoded as a sigma-delta sequence;
- a modulator comprising a first input coupled to the analog input and a second input coupled to the output of the modulating source;
- an analog filter coupled to the output of the modulator;
- and
- a sampling circuit coupled to the output of the analog filter.
A communication receiver comprising:
- a modulating source comprising an output that generates an impulse response encoded as a sigma-delta sequence;
- a plurality of switching modulators comprising a control input coupled to the modulating source and an input coupled to a communication signal;
- a plurality of analog filters each comprising an input coupled to at least one switching modulator;
- and
- a plurality of sampling circuits coupled to at least one of the analog filters.
A receiver comprising:
- a first plurality of commutating modulators comprising control inputs configured to receive in-phase sequences of a modulating signal and analog signal inputs configured to receive a communication signal;
- a second plurality of commutating modulators comprising control inputs configured to receive quadrature-phase sequences of the modulating signal and analog signal inputs configured to receive the communication signal;
- a first plurality of analog filters coupled to the first plurality of commutating modulators;
- a second plurality of analog filters coupled to the second plurality of commutating modulators;
- a first plurality of sampling circuits coupled to the first plurality of analog filters;
- and
- a second plurality of sampling circuits coupled to the second plurality of analog filters, wherein the modulating signal comprises a filter impulse response encoded as a sigma-delta sequence.
A multi-mode communication receiver comprising:
- an input configured to receive an analog signal;
- a programmable modulating source comprising an output that generates an impulse response encoded as a sigma-delta sequence;
- and
- a modulator comprising a first input coupled to the output of the modulating source and a second input coupled to the analog signal.
In a communications receiver, an improvement comprising a filter for an analog signal comprising:
- a modulation source having an output comprising an impulse response encoded as a sigma-delta sequence;
- a switching modulator having a signal input coupled to the analog signal and a control input coupled to the output of the modulation source;
- an analog filter coupled to an output of the switching modulator;
- and
- a sampler coupled to an output of the analog filter.
In a correlation receiver, an improvement comprising a bilinear multiplier comprising:
- a switching modulator having a control input driven by an impulse response encoded as a sigma-delta modulated sequence and a signal input coupled to an analog signal.
In a multi-mode communication receiver, an improvement comprising a programmable filter for an analog signal coupled to a communications signal, comprising:
- a plurality of modulating signals, wherein each of the modulating signals comprises a filter impulse response encoded as a sigma-delta sequence;
- and
- a switching modulator having a control input coupled to at least one of the modulating signals and a signal input coupled to the analog signal.
Dependencies are inferred from the claim text.