Direct conversion delta-sigma receiver
AssigneeTechnoConcepts, Inc.
InventorRonald M. Hickling
Life of this patent
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Abstract
A wireless receiver receives a wireless signal by inverting the polarity of an incoming waveform on every one half clock cycle of a conversion clock to produce a commutated waveform and converting said commutated waveform to a series of representative digital values using a delta-sigma modulator clocked by said conversion clock. In this way, the receiver operates over a large dynamic range and the use of automatic gain control in the front end may be eliminated.
Claims19
A method of receiving a wireless transmission comprising the steps of:
- inverting the polarity of an incoming waveform corresponding to said wireless transmission on every one half clock cycle of a conversion clock having a predetermined frequency to produce a commutated waveform, thereby translating said incoming waveform downward in frequency;
- and
- converting said commutated waveform to a series of representative digital values using a delta-sigma modulator clocked by said conversion clock operating at said predetermined frequency.
A circuit employed in a receiver comprising:
- a continuous time commutator configured to be coupled to a digital conversion clock and configured to invert the polarity of an incoming communication signal applied to an input port on every half clock cycle of said digital conversion clock having a predetermined frequency and to produce a commutated signal at an output port, thereby translating said incoming signal downward in frequency;
- and
- a delta-sigma modulator having a clock input port coupled to said digital conversion clock operating at said predetermined frequency, having a signal input port coupled to said output port of said continuous time commutator and having an output port configured to produce a series of digital values representative of a modulation waveform carried by said incoming signal.
An apparatus for receiving a wireless transmission comprising:
- means for inverting the polarity of an incoming waveform representative of said wireless transmission on every one half clock cycle of a conversion clock having a predetermined frequency to produce a commutated waveform, thereby translating said incoming waveform downward in frequency;
- and
- means for converting said commutated waveform to a series of representative digital values using a delta-sigma modulator clocked by said conversion clock operating at said predetermined frequency.
The apparatus of claim 18, further comprising means for filtering an antenna signal to prevent aliasing out-of-band signal and noise power into a desired signal band, said means for filtering producing said incoming waveform, and wherein a frequency of said conversion clock is selected from a range of frequencies passed in said means for filtering.
A method of receiving a wireless transmission comprising:
- multiplying an incoming waveform by +1 and −1 on alternating half cycles of a conversion clock to produce a commutated waveform, thereby translating the incoming waveform downward in frequency;
- converting the commutated waveform to a series of representative digital values using a delta-sigma modulator clocked at a frequency equal to the conversion clock;
- wherein the incoming waveform comprises a baseband frequency signal modulated at a carrier frequency, and the conversion clock has a frequency of approximately the carrier frequency;
- whereby the multiplying step produces a signal of approximately the baseband frequency;
- and
- wherein the incoming waveform has a frequency of greater than 1 MHz, and the multiplying and converting steps downconvert the incoming signal directly to a baseband frequency without needing to first downconverting the incoming signal to an intermediate frequency.
Dependencies are inferred from the claim text.