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US 6,788,232 B1Granted
Sigma delta modulator
AssigneeBerkana Wireless, Inc.
InventorSang Oh Lee
Life of this patent
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Abstract
A sigma delta modulator system and a method for modulating a signal are described. The sigma delta modulator includes a plurality of cascading stages, an output coupled to the plurality of the cascading stages via a plurality of feedback connections, and a feedforward connection coupled between a selected one of the plurality of cascading stages and a point closer to the output interface of the sigma delta modulator.
Claims8
A sigma delta modulator comprising:
- a plurality of cascading stages;
- an output interface coupled to the plurality of the cascading stages via a plurality of feedback connections, the output interface generating a modulated output signal corresponding to a randomized bit sequence representing a frequency range of the sigma delta modulator;
- a feedforward connection coupled between a selected one of the plurality of cascading stages and a point closer to the output interface of the sigma delta modulator, wherein the feedforward connection adds a zero to the randomized bit sequence in a low frequency range of the sigma delta modulator to stabilize the modulated output signal;
- and
- an adder corresponding to each of the cascading stages and producing an output signal by adding an amplified feedback output with a previous stage amplified output.
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A method for modulating an input signal to produce a modulated output signal, comprising:
- cascading a plurality of stages;
- generating the modulated output signal to correspond to a randomized bit sequence representing a frequency range of a sigma delta modulator;
- coupling the modulation output to the plurality of stages via a plurality of feedback connections;
- feeding forward the modulated output signal over a feedforward connection between a selected one of the plurality of cascading stages and a point closer to an output interface connected to the modulated output, wherein the feedforward connection adds a zero to the randomized bit sequence in a low frequency range of the frequency range of the sigma delta modulator;
- and
- adding an amplified feedback output with a previous stage amplified output to produce an output signal.
3 more elements
Dependencies are inferred from the claim text.