US5621345A — In-phase and quadrature sampling circuit

Claim 1

Independent Claim 104 words

A circuit that provides samples of in-phase and quadrature components of an input waveform comprising: an oversampling ADC that receives the input waveform and converts the input waveform to digital samples having an input frequency at an oversampling rate; a first digital decimation filter, coupled to the ADC, that receives the digital samples from the ADC and provides the in-phase component samples having a center frequency different from the input frequency; and a second digital decimation filter, coupled to the ADC, that receives the digital samples from the ADC and provides the quadrature component samples having a center frequency different from the input frequency.

Claim 2

Dependent Claim 104 words

A circuit that provides samples of in-phase and quadrature components of an input waveform comprising: an oversampling ADC that receives the input waveform and converts the input waveform to digital samples having an input frequency at an oversampling rate; a first digital decimation filter, coupled to the ADC, that receives the digital samples from the ADC and provides the in-phase component samples having a center frequency different from the input frequency; and a second digital decimation filter, coupled to the ADC, that receives the digital samples from the ADC and provides the quadrature component samples having a center frequency different from the input frequency.

Claim 3

Dependent Claim 15 words

The circuit as claimed in claim 1 wherein the oversampling ADC includes a sigma-delta ADC.

Claim 4

Dependent Claim 16 words

The circuit as claimed in claim 2 wherein the sigma-delta ADC includes a one-bit sigma-delta ADC.

Claim 5

Dependent Claim 43 words

The circuit as claimed in claim 1 wherein each of the first and second digital filters includes a multi-tap decimation/demodulation filter, and wherein the demodulation performed by the first filter is approximately 90 degrees out of phase with that of the second filter.

Claim 6

Dependent Claim 46 words

The circuit as claimed in claim 4 wherein the first digital filter includes multiple coefficients, at least one coefficient corresponding to each filter tap, each coefficient being equal to the product of a corresponding constant decimation filter coefficient value and a respective cosine wave sample value.

Claim 7

Dependent Claim 33 words

The circuit as claimed in claim 5 further including a memory element, coupled to the first digital filter, that stores a plurality of coefficients, at least two coefficients corresponding to each filter tap.

Claim 8

Dependent Claim 31 words

The circuit as claimed in claim 6 further including a processor, coupled to the memory element and the first digital filter, that dynamically computes the coefficients of the first digital filter.

Claim 9

Dependent Claim 46 words

The circuit as claimed in claim 4 wherein the second digital filter includes multiple coefficients, at least one coefficient corresponding to each filter tap, each coefficient being equal to the product of a corresponding constant decimation filter coefficient value and a respective sine wave sample value.

Claim 10

Dependent Claim 33 words

The circuit as claimed in claim 8 further including a memory element, coupled to the second digital filter, that stores a plurality of coefficients, at least two coefficients corresponding to each filter tap.

Claim 11

Dependent Claim 31 words

The circuit as claimed in claim 9 further including a processor, coupled to the memory element and the second digital filter, that dynamically computes the coefficients of the second digital filter.

Claim 12

Dependent Claim 18 words

The circuit as claimed in claim 4 wherein each of the digital filters includes a one-bit digital filter.

Claim 13

Independent Claim 81 words

A method for providing in-phase and quadrature component samples of an input waveform comprising the steps of: converting the input waveform to digital samples having an input frequency at an oversampling rate; with a first digital decimation filter, providing, from the digital samples, the in-phase component samples having a center frequency different from the input frequency; and with a second digital decimation filter, providing, from the digital samples, the quadrature component samples having a center frequency different from the input frequency.

Claim 14

Independent Claim 81 words

A method for providing in-phase and quadrature component samples of an input waveform comprising the steps of: converting the input waveform to digital samples having an input frequency at an oversampling rate; with a first digital decimation filter, providing, from the digital samples, the in-phase component samples having a center frequency different from the input frequency; and with a second digital decimation filter, providing, from the digital samples, the quadrature component samples having a center frequency different from the input frequency.

Claim 15

Dependent Claim 21 words

A method as claimed in claim 12 wherein the step of converting includes the step of sigma-delta modulating the input waveform.

Claim 16

Dependent Claim 23 words

A method as claimed in claim 12 wherein the first step of providing includes the step of demodulating and decimating the digital samples.

Claim 17

Dependent Claim 23 words

A method as claimed in claim 12 wherein the second step of providing includes the step of demodulating and decimating the digital samples.

Claim 18

Dependent Claim 90 words

A circuit that provides in-phase and quadrature component samples of an input waveform comprising: means for converting the input waveform to digital samples having an input frequency at an oversampling rate; first decimation means, coupled directly to the means for converting, for providing from the digital samples the in-phase component samples having a center frequency different from the input frequency; and second decimation means, coupled directly to the means for converting, for providing from the digital samples the quadrature component samples having a center frequency different from the input frequency.

Claim 19

Dependent Claim 90 words

A circuit that provides in-phase and quadrature component samples of an input waveform comprising: means for converting the input waveform to digital samples having an input frequency at an oversampling rate; first decimation means, coupled directly to the means for converting, for providing from the digital samples the in-phase component samples having a center frequency different from the input frequency; and second decimation means, coupled directly to the means for converting, for providing from the digital samples the quadrature component samples having a center frequency different from the input frequency.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-04-14	2000-10-14	2001-04-15	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-04-14	2004-10-14	2005-04-15	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-04-14	2008-10-14	2009-04-15	$7700.00	Window Closed / Lapsed

In-phase and quadrature sampling circuit

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag