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.
Claims33
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 each 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 multiplier having a first input coupled to the output of the modulating source and a second input coupled to the analog signal;
- wherein the modulating source comprises a plurality of sigma-delta modulators that generate a plurality of sigma-delta sequences.
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;
- a modulator comprising a multiplier having a first input coupled to the output of the modulating source and a second input coupled to the analog signal;
- wherein the modulating source comprises a plurality of sigma-delta modulaters that generate a plurality of sigma-delta sequences;
- and a multiplexer and an amplifier, the multiplexer being coupled to each sigma-delta modulator and to the amplifier.
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;
- wherein the switching modulator multiplies the analog signal at a frequency of at least one of the modulating signals.
Dependencies are inferred from the claim text.