US3863030A
Expired / Lapsed
US
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Pcm tone receiver using digital spectrum analysis
Assignee: AG Communication Systems Corp
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Filing: 1972-11-24
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Granted: 1975-01-28
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Expires: 1992-11-24
Abstract
Abstract Method and apparatus for detecting one or more tone signals in a PCM signal corresponding to an original analog voltage, without converting the PCM signal to analog, including sequentially monitoring samples of the PCM signal using an expression, Vf, in Fourier spectrum analysis selectively for the respective tone signals to be detected, and storing and accumulating the magnitude of Vf, wherein the determined magnitude of Vf for each tone signal is proportional to the magnitude of the tone signal in the original analog signal. An improved method and apparatus for detecting one or more tone signals in a PCM signal, Vc, corresponding to an original analog voltage, Va. The accumulated magnitude, Vf, is compared with another accumulated quantity, Vr, derived from the incoming PCM signal, to determine if the amplitude of the respective tone exceeds a certain percentage of that of the entire signal. This allows the detector to operate correctly under varying levels of the analog signal.
Inventors
- 👤 Jeffrey P Mills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:26
CPC Classifications
H; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/44; H04Q1/444; H04Q1/45; H04Q1/457; H04Q1/4575; H04J; H04J3/00; H04J3/02; H04J3/12
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
68 words
The method of deriving information for detecting at least one tone, f1, froM a PCM signal, Vc, corresponding to an original analog signal, Va, comprising the steps of: sequentially providing one of a plurality of samples of said PCM signal during a discrete time interval from t 1 to t n; automatically evaluating said sequential samples of said PCM signal, Vc, during said time interval using the expression:
Claim 2
Independent Claim
68 words
The method of deriving information for detecting at least one tone, f1, froM a PCM signal, Vc, corresponding to an original analog signal, Va, comprising the steps of: sequentially providing one of a plurality of samples of said PCM signal during a discrete time interval from t 1 to t n; automatically evaluating said sequential samples of said PCM signal, Vc, during said time interval using the expression:
Claim 3
Dependent Claim
98 words
The method of claim 1, wherein said storing of said algebraic sum corresponding to Real Vf includes the steps of: storing an initial Real Vf determined for an initial sample of said PCM signal; reading from storage said initial Real Vf; determining a sub-total Real Vf corresponding to the combination of said initial Real Vf and a second Real Vf determined for the next sample of said PCM signal; storing said sub-total Real Vf; repeating said steps during said time interval so that at the end thereof, the total Real Vf for said PCM signal samples is stored.
Claim 4
Dependent Claim
94 words
The method of claim 2, wherein said storing of said algebraic sum corresponding to Imag. Vf includes the steps of: storing an initial Imag. Vf determined for an initial sample of said PCM signal; reading from storage said initial Imag. Vf; determining a sub-total Imag. Vf corresponding to said initial Imag. Vf and a second Imag. Vf determined for the next sample of said PCM signal; storing said sub-total Imag. Vf; repeating said steps during said time interval so that at the end thereof, the total Imag. Vf for said PCM samples is stored.
Claim 5
Dependent Claim
29 words
The method of claim 1, including, sequentially determining from said PCM signal, a quantity, Vr, proportional to the amplitude of said analog signal, Va, and storing said quantity, Vr.
Claim 6
Dependent Claim
24 words
The method of claim 4, including comparing the stored quantity, Vr, to said magnitude (Real Vf) to determine the presence of a tone signal.
Claim 7
Dependent Claim
24 words
The method of claim 4, including comparing the stored quantity, Vr, to said magnitude (Imag. Vf) to determine the presence of a tone signal.
Claim 8
Dependent Claim
57 words
A PCM tone signal receiver for deriving information for detecting at least one tone signal, f1, from a plurality of samples of a PCM signal, Vc, corresponding to an original analog signal, Va, comprising: means for evaluating said samples of saiD PCM signal, Vc, sequentially during a time interval t 1 to t n using the expression:
Claim 9
Dependent Claim
57 words
A PCM tone signal receiver for deriving information for detecting at least one tone signal, f1, from a plurality of samples of a PCM signal, Vc, corresponding to an original analog signal, Va, comprising: means for evaluating said samples of saiD PCM signal, Vc, sequentially during a time interval t 1 to t n using the expression:
Claim 10
Dependent Claim
122 words
A PCM signal receiver as claimed in claim 7, wherein said means for storing the algebraic sum corresponding to Real Vf comprises means for accumulating sub-total Real Vf values including; means for storing an initial sub-total Real Vf determined for an initial sample of said PCM signal in said first accumulator means; means for reading said initial Real Vf from said first accumulator means; means for determining a sub-total Real Vf corresponding to the combination of said initial Real Vf and a second Real Vf determined for the next sample of said PCM signal and providing a corresponding output; selector means for selectively coupling said output to said first accumulator means for storing said sub-total Real Vf in said first accumulator means.
Claim 11
Dependent Claim
121 words
A PCM signal receiver as claimed in claim 8, wherein said means for storing the algebraic sum corresponding to Imag. Vf comprises means for accumulating sub-total Imag. Vf values including; means for storing an initial sub-total Imag. Vf determined for an initial sample of said PCM signal in said second accumulator means; means for reading said initial Imag. Vf from said second accumulator means; means for determining a sub-total Imag. Vf corresponding to the combination of said initial Imag. Vf and a second Imag. Vf determined for the next sample of said PCM signal and providing a corresponding output; said selector means selectively coupling said output to said second accumulator means for storing sub-total Imag. Vf in said second accumulator means.
Claim 12
Dependent Claim
174 words
A PCM signal receiver as claimed in claim 9 for detecting one or more tone signals, f1 to fn, from a plurality of samples of said PCM signal, said detector further including, a plurality of said first and second accumulator means for respectively storing said sub-total and total Real Vf and Imag. Vf corresponding to each of said tone signals; a plurality of said reference means for providing said reference quantities corresponding to each of said tone signals; reference quantity selector means coupled to said reference mEans for respectively sequentially selecting each of said reference quantities; and timing control means coupled to said means responsive to said reference quantities and to said plurality of first and second accumulator means for sequentially determining Real Vf and Imag. Vf for each of said plurality of PCM signal samples and storing the respective algebraic sums in respective accumulator means, the magnitude of the complex number represented by said respective algebraic sums being proportional to the magnitudes of said respective tone signals present in said original analog signal.
Claim 13
Dependent Claim
42 words
A PCM signal receiver as claimed in claim 7, including, means responsive to said PCM signal samples for sequentially determining a quantity, Vr, proportional to the amplitude of said analog signal, Va, and third accumulator storage means for storing said quantity, Vr.
Claim 14
Dependent Claim
32 words
A PCM signal receiver as claimed in claim 11, including comparator means for comparing said stored quantity, Vr, to said stored magnitude (Real Vf) to determine the presence of a tone signal.
Claim 15
Dependent Claim
32 words
A PCM signal receiver as claimed in claim 11, including comparator means for comparing the stored quantity Vr to said stored magnitude (Imag. Vf) to determine the presence of a tone signal.
Claim 16
Dependent Claim
59 words
A PCM tone signal receiver as claimed in claim 7, including: means for providing a reference quantity, K, associated with said expression corresponding to said tone signal, said reference quantity, K, being chosen according to the desired threshold of detection of said tone signal, f1; means for measuring the strength of said original analog signal, Va, using the expression:
Claim 17
Dependent Claim
56 words
A PCM tone signal receiver for deriving information for detecting at least one tone signal, f1, from a plurality of samples of a PCM signal, Vc, corresponding to an original analog signal, Va, comprising: means for evaluating said samples of said PCM signal sequentially during a time interval t 1 to t n using the expression:
Claim 18
Dependent Claim
56 words
A PCM tone signal receiver for deriving information for detecting at least one tone signal, f1, from a plurality of samples of a PCM signal, Vc, corresponding to an original analog signal, Va, comprising: means for evaluating said samples of said PCM signal sequentially during a time interval t 1 to t n using the expression:
Claim 19
Dependent Claim
60 words
A PCM tone signal receiver as claimed in claim 15, including: means for providing a reference quantity, K, associated with said expression corresponding to said tone sIgnal, said reference quantity, K, being chosen according to the desired threshold of detection of said tone signal, f1; means for measuring the average strength of said original analog signal, Va, using the expression:
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) | 1978-01-27 | 1978-07-29 | 1979-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-27 | 1982-07-29 | 1983-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-27 | 1986-07-29 | 1987-01-28 | $7700.00 | Window Closed / Lapsed |