Signal processing architecture for modulation and interpolation
First Claim
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1. A system for processing a digital signal comprising:
- a. an input for receiving the digital signal;
b. a modulator operatively coupled to the input, the modulator configured to produce a frequency-shifted digital signal;
c. An interpolator operatively coupled to the modulator, the interpolator configured to produce an oversampled digital signal from the frequency-shifted signal; and
d. A filter operatively coupled to the interpolator, the filter configured to produce a filtered digital signal;
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Abstract
A system and method for oversampling and modulating a digital data stream. A programmable quadrature interpolating filter is provided which allows the passband of the output signal to be selected from a set of mode selections. The set of mode selections provide overlapping passbands spanning the Nyquist range of the filter. The filter allows a signal to be shifted to a desired carrier frequency before the signal is oversampled and filtered, reducing power consumption in devices such as digital-to-analog converters.
12 Citations
19 Claims
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1. A system for processing a digital signal comprising:
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a. an input for receiving the digital signal;
b. a modulator operatively coupled to the input, the modulator configured to produce a frequency-shifted digital signal;
c. An interpolator operatively coupled to the modulator, the interpolator configured to produce an oversampled digital signal from the frequency-shifted signal; and
d. A filter operatively coupled to the interpolator, the filter configured to produce a filtered digital signal;
- View Dependent Claims (2, 3, 4, 5, 6)
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7. A programmable interpolation filter for interpolating and filtering a complex digital data input stream, the frequency spectrum of the stream characterized by a center frequency and a bandwidth, the filter comprising:
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a. a programmable multiplexer configured to receive the input stream and output a plurality of signals representing the input stream, the multiplexer output signals corresponding to a given multiplexer mode chosen from a plurality of modes;
b. a first interpolation filter;
the first filter configured to receive and interpolate at least one signal from the multiplexer and produce an in-phase output signal; and
c. a second interpolation filter;
the second filter configured to receive and interpolate at least one signal from the multiplexer and produce a quadrature output signal,wherein the plurality of multiplexer modes are configured so that at least one mode allows the filter to pass the input stream with the frequency spectrum of the stream substantially unchanged when the stream center frequency is anywhere within a range of frequencies and the bandwidth is less than a given bandwidth. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for processing a digital input data stream the method comprising:
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a. receiving the digital input data stream;
b. modulating the digital input data stream and producing a frequency-shifted data stream; and
c. interpolating and filtering the frequency-shifted data stream to produce an oversampled frequency-shifted data stream representative of the digital input data stream. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification