US4296374A
Expired / Lapsed
US
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Wideband digital spectrometer
Assignee: AT&T Inc
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Filing: 1979-10-11
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Granted: 1981-10-20
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Expires: 1999-10-11
Abstract
Abstract The present invention relates to a wideband digital spectrometer capable of obtaining the Fourier power spectrum of a combination of an input signal, using the Walsh functions. The input signal is low-pass filtered (10) at a cutoff frequency f c , then sampled at a rate of 2f c (12) to provide N sequences representative of the digitized input signal. Each one of the N sequences is combined with a separate one of the N Walsh functions (14), and the Walsh power spectrum of each one of these N combinations is then computed (16). These N Walsh power spectrum components are applied to an N×N Walsh-Fourier power transformer (18) which generates the desired N Fourier power spectrum components.
Inventors
- 👤 Paul S. Henry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:03
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/16; G01R23/165; G01R23/167
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
151 words
A wideband digital spectrometer comprising: low-pass filtering means (10) for low-pass filtering an input signal; means (12) connected to the output of said filtering means capable of converting an analog signal to a plurality of N digital signals, each digital signal having M bits of resolution; Walsh function generating means (14) for generating a plurality of N Walsh functions, each Walsh function being either +1 or -1; means (18) capable of performing an N×N Walsh-Fourier power transformation characterized in that the wideband digital spectrometer further comprises power spectrum generating means (16) connected to both the output of the analog-to-digital converting means (12) and the output of the Walsh function generating means (14) and capable of generating as an output a signal representative of a Walsh power spectrum of said analog-to-digital converting means, the output of said power spectrum generating means being connected to the input of the Walsh-Fourier power transformation means.
Claim 2
Dependent Claim
151 words
A wideband digital spectrometer comprising: low-pass filtering means (10) for low-pass filtering an input signal; means (12) connected to the output of said filtering means capable of converting an analog signal to a plurality of N digital signals, each digital signal having M bits of resolution; Walsh function generating means (14) for generating a plurality of N Walsh functions, each Walsh function being either +1 or -1; means (18) capable of performing an N×N Walsh-Fourier power transformation characterized in that the wideband digital spectrometer further comprises power spectrum generating means (16) connected to both the output of the analog-to-digital converting means (12) and the output of the Walsh function generating means (14) and capable of generating as an output a signal representative of a Walsh power spectrum of said analog-to-digital converting means, the output of said power spectrum generating means being connected to the input of the Walsh-Fourier power transformation means.
Claim 3
Dependent Claim
84 words
A wideband digital spectrometer in accordance with claim 1 characterized in that the power spectrum generating means further comprises a plurality of N separate channels (16 1 -16 N ), each channel comprising a first input coupled to receive a separate one of the N identical digital signals and a second input coupled to receive a separate corresponding one of the N distinct Walsh functions, and capable of generating a signal representative of the Walsh power spectrum of the analog-to-digital converting means associated therewith.
Claim 4
Dependent Claim
144 words
A wideband digital spectrometer in accordance with claim 1 or 2 characterized in that the power spectrum generating means comprises a plurality of N separate channels (16 1 -16 N ) each channel receiving both a separate one of the N,M-bit, identical digital signals from the analog-to-digital converting means and a corresponding separate one of the N distinct Walsh functions generated by the Walsh function generating means and comprising: means (20,22) capable of multiplying together corresponding bits of said received M-bit digital signal and said received Walsh function to generate a time dependent product thereof; and processing means (24) comprising a plurality of M inputs, each input coupled with a separate one of the M outputs of said multiplying means, capable of generating at an output thereof a signal representative of the average Walsh power spectrum of the input to said analog-to-digital converting means.
Claim 5
Dependent Claim
157 words
A wideband digital spectrometer in accordance with claim 3 characterized in that the multiplying means comprises: a plurality of M exclusive-OR gates (20 1 -20 M ), each gate comprising a first input coupled to receive a separate bit of the associated M-bit digital signal and a second input coupled to receive the associated Walsh function, with gate 20 1 coupled to receive the most significant bit of the M-bit digital signal and gate 20 M coupled to receive the least significant bit of the M-bit digital signal, and capable of generating therefrom an exclusive-OR function for each gate of said plurality of M exclusive-OR gates; and a plurality of M counters (22 1 -22 M ), each counter comprising an input coupled to receive a separate one of M outputs from said plurality of M exclusive-OR gates and capable of generating as an output the accumulated value of the output of the exclusive-OR gate associated therewith.
Claim 6
Dependent Claim
156 words
A wideband digital spectrometer in accordance with claim 3 characterized in that the processing means comprises: means (26) capable of performing an M-bit addition of a set of signals present at the plurality of M inputs to the processing means and generating a weighted sum of said plurality of M inputs; means (28) connected to the output of said adding means and capable of squaring an input signal to generate as an output a signal representative of the square of said input signal applied thereto; and means (30) connected to the output of said squaring means capable of both storing an input value of a signal received from said squaring means in an immediately previous time period and averaging the received input signal in a present time period with a previously computed average value to generate at the output thereof a signal representative of the average Walsh power spectrum of the input to the multiplying means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |