Spread spectrum demodulation using a subsampling communication receiver architecture
AssigneeTexas Instruments Incorporated
InventorsKhurram Muhammad, Carl Panasik, Dirk Leipold
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Abstract
A first periodic voltage waveform (20) is downconverted into a second periodic voltage waveform (35, 36). A plurality of temporally distinct samples (SA1, SA2, . . . ) respectively indicative of areas under corresponding fractional cycles of the first voltage waveform are obtained. The samples are obtained in response to a control signal indicative of a code used to produce the first voltage waveform, and the samples are combined to produce the second voltage waveform.
Claims43
An apparatus for downconverting a first periodic voltage waveform into a second periodic voltage waveform, comprising:
- an input for receiving the first voltage waveform;
- a sampler having a control input for receiving a control signal indicative of a code used to produce the first voltage waveform, said sampler coupled to said first-mentioned input, and said sampler responsive to said control signal for obtaining from the first voltage waveform a plurality of temporally distinct samples respectively indicative of areas under corresponding fractional-cycles of the first voltage waveform;
- and
- a combiner coupled to said sampler for combining the samples to produce the second voltage waveform.
17 A method of downconverting a first periodic voltage waveform into a second periodic voltage waveform, comprising:
- providing a control signal indicative of a code used to produce the first voltage waveform;
- in response to said control signal, obtaining from the first voltage waveform a plurality of temporally distinct samples respectively indicative of areas under corresponding fractional-cycles of the first voltage waveform;
- and
- combining the samples to produce the second voltage waveform.
The method of claim 17, wherein said code includes a sequence of code symbols.
The method of claim 17, including producing said control signal based on said code and an information-carrying waveform used in combination with said code to produce the first voltage waveform.
The method of claim 17, wherein the first voltage waveform is an RF waveform.
A communication receiving apparatus, comprising:
- an input for receiving a communication signal formed as a first periodic voltage waveform;
- a mixer coupled to said input for down converting the first periodic voltage waveform into a second periodic voltage waveform, including a sampler having a control input for receiving a control signal indicative of a code used to produce the first voltage waveform, said sampler responsive to said control signal for obtaining from the first voltage waveform a plurality of temporarily distinct samples respectively indicative of areas under corresponding fractional-cycles of the first voltage waveform, and a combiner coupled to said sampler for combining the samples to produce the second voltage waveform, and
- a signal processing portion coupled to said mixer for receiving and processing the second voltage waveform.
The method of claim 17, wherein said fractional cycles are one of half cycles and quarter cycles.
Dependencies are inferred from the claim text.