US3740655A
Expired / Lapsed
US
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Digital generation of quadrature samples
Assignee: General Electric Co
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Filing: 1971-11-24
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Granted: 1973-06-19
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Expires: 1991-11-24
Abstract
Abstract A method and apparatus for generating digitized quadrature samples which approximate the sampled complex envelope of an input waveform by digitally sampling the input signal and applying the resultant digital samples to a digital processing system to obtain pairs of quadrature samples of the input signal. The input digital samples are digitally combined, delayed, and multiplied by the digital processor to form the quadrature samples. An alternative method and apparatus takes digital samples from a plurality of input signals, applies the digital samples to an alternative form of digital processor, and generates multiplexed quadrature samples of the input signal.
Inventors
- 👤 F Dickey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:48
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/68; H03; H03H; H03H17/00; H03H17/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
225 words
A method of generating digitized quadrature samples approximating the sampled complex envelope of an input signal S(t) relative to a carrier frequency fc, including the steps of: a. sampling said input signal at time designated t 0 to obtain a sample S(0); b. converting said sample into a digital sample and storing such digital sample; c. repeating steps (a) and (b) for a selected number, n, of times occurring at regular intervals T1 1/(4fc) so as to store a set of n + 1 digital samples designated S(0), S(T1), S(2T1) . . . S(nT1); d. repeatedly performing the previous steps with starting times differing by a time interval T2 mT1, where m is a selected integer, so as to generate successive sets of n + 1 digital samples the samples within which sets are at uniform intervals T1 for any selected value of m, the k''th such successive set of digital samples being designated S(kT2), S(kT2 + T1), S(kT2 + 2T1) . . . S(kT2 + nT1), and each time replacing the stored previous set with the succeeding set whereby k takes on successive integer values; and e. generating during each time interval T2 a pair of quadrature samples designated I(kT) and Q(kT) by digitally processing the stored samples according to the relations: I(kT2) real part of R(kT2), Q(kT2) imaginary part of the R(kT2), where:
Claim 2
Independent Claim
225 words
A method of generating digitized quadrature samples approximating the sampled complex envelope of an input signal S(t) relative to a carrier frequency fc, including the steps of: a. sampling said input signal at time designated t 0 to obtain a sample S(0); b. converting said sample into a digital sample and storing such digital sample; c. repeating steps (a) and (b) for a selected number, n, of times occurring at regular intervals T1 1/(4fc) so as to store a set of n + 1 digital samples designated S(0), S(T1), S(2T1) . . . S(nT1); d. repeatedly performing the previous steps with starting times differing by a time interval T2 mT1, where m is a selected integer, so as to generate successive sets of n + 1 digital samples the samples within which sets are at uniform intervals T1 for any selected value of m, the k''th such successive set of digital samples being designated S(kT2), S(kT2 + T1), S(kT2 + 2T1) . . . S(kT2 + nT1), and each time replacing the stored previous set with the succeeding set whereby k takes on successive integer values; and e. generating during each time interval T2 a pair of quadrature samples designated I(kT) and Q(kT) by digitally processing the stored samples according to the relations: I(kT2) real part of R(kT2), Q(kT2) imaginary part of the R(kT2), where:
Claim 3
Dependent Claim
36 words
A method of generating quadrature samples as defined in claim 1, wherein the value of m is set equal to 4 whereby the value of R(kT2) reduces to: R(kT2) (-j)mk ( ( 1/4S(kT1)-3/4S(kT1-2T2)) + j(3/4S(kT1-T2)-1/4S(kT1-3T2)) )
Claim 4
Independent Claim
160 words
A method of generating digitized quadrature samples approximating the sampled complex envelope of an input signal relative to a carrier frequency fc, including the steps of: a. sampling said real input signal S(t) at a time T1, where T1 equals 1/(4fc), to obtain input signal samples; b. converting said input signal samples to digital samples; c. delaying said digital samples one time period T1, and multiplying said digital samples by three to provide a first signal; d. delaying said digital samples three time periods T1 to provide a second signal; e. subtracting said second signal from said first signal to provide a third signal; f. delaying said digital samples two time periods T1 and multiplying said digital samples by three to provide a fourth signal; g. subtracting said fourth signal from said digital samples to provide a fifth signal; h. communicating said third signal to a first output terminal; and i. communicating said fifth signal to a second output terminal.
Claim 5
Independent Claim
160 words
A method of generating digitized quadrature samples approximating the sampled complex envelope of an input signal relative to a carrier frequency fc, including the steps of: a. sampling said real input signal S(t) at a time T1, where T1 equals 1/(4fc), to obtain input signal samples; b. converting said input signal samples to digital samples; c. delaying said digital samples one time period T1, and multiplying said digital samples by three to provide a first signal; d. delaying said digital samples three time periods T1 to provide a second signal; e. subtracting said second signal from said first signal to provide a third signal; f. delaying said digital samples two time periods T1 and multiplying said digital samples by three to provide a fourth signal; g. subtracting said fourth signal from said digital samples to provide a fifth signal; h. communicating said third signal to a first output terminal; and i. communicating said fifth signal to a second output terminal.
Claim 6
Dependent Claim
56 words
A method of generating quadrature samples as defined in claim 3 including the additional steps of: a. sampling said third signal applied to said first output terminal, at time periods T2, where T2 mT1 and m is an integer; and b. sampling said fifth signal applied to said second output terminal at said time periods T2.
Claim 7
Independent Claim
203 words
An apparatus for generating digitized quadrature samples approximating the sampled complex envelope of an input waveform S(t) relative to a carrier frequency fc, comprising: a. means for receiving said input signal S(t); b. signal sampler means for sampling said input signal S(t) at a periodic interval of T1, where T1 equals 1/(4fc), to obtain input signal samples; c. analog-to-digital conversion means for converting said input signal samples to digital samples; d. means for delaying said digital samples one time period T1 and for multiplying said digital samples by a factor of three to provide a first signal; e. means for delaying said digital samples three time periods T1 to provide a second signal; f. means for subtracting said second signal from said first signal to provide a third signal; g. means for delaying said digital samples two time periods T1 and for multiplying said digital samples by a factor of three to provide a fourth signal; h. mean for subtracting said fourth signal from said digital samples to provide a fifth signal; i. first and second output terminals; j. means for communicating said third signal to said first output terminal; and k. means for communicating said fifth signal to said second output terminal.
Claim 8
Independent Claim
203 words
An apparatus for generating digitized quadrature samples approximating the sampled complex envelope of an input waveform S(t) relative to a carrier frequency fc, comprising: a. means for receiving said input signal S(t); b. signal sampler means for sampling said input signal S(t) at a periodic interval of T1, where T1 equals 1/(4fc), to obtain input signal samples; c. analog-to-digital conversion means for converting said input signal samples to digital samples; d. means for delaying said digital samples one time period T1 and for multiplying said digital samples by a factor of three to provide a first signal; e. means for delaying said digital samples three time periods T1 to provide a second signal; f. means for subtracting said second signal from said first signal to provide a third signal; g. means for delaying said digital samples two time periods T1 and for multiplying said digital samples by a factor of three to provide a fourth signal; h. mean for subtracting said fourth signal from said digital samples to provide a fifth signal; i. first and second output terminals; j. means for communicating said third signal to said first output terminal; and k. means for communicating said fifth signal to said second output terminal.
Claim 9
Dependent Claim
42 words
Apparatus as defined in claim 5 further including first and second samplers; said samplers being respectively connected to said first and second output terminals and operative to sample their outputs at time periods T2 where T2 mT1 and m is an integer.
Claim 10
Dependent Claim
241 words
Apparatus for generating digitized quadrature samples approximating the sampled complex envelopes of each of a plurality of input signals relative to a carrier frequency fc, comprising: a. means for receiving a plurality of input signals; b. signal sampler means for sampling each of said input signals at a periodic interval of T1, where T1 equals 1/(4fc), to obtain input signal samples of each of said input signals; c. analog-to-digital conversion means for converting said input signal samples to digital samples; and d. a digital system for processing said digital samples comprising: i. switching means having inputs to receive said digital samples and further having first, second, third and fourth terminals, said switching means operating to selectively communicate said digital samples to said terminals; ii. first and second outputs; iii. a first signal processor channel comprising a first combiner having a positive input connecting to said first terminal and further having a negative input, a first multiplier and first delay register connected in series between said second terminal and said negative input of said first combiner; and means for connecting said combiner to said first output; and iv. a second signal processor channel comprising a second combiner having a positive input and a negative input; a second multiplier connected between said third terminal and said positive input of said second combiner; a second delay register connected between said fourth terminal and said negative input of said second combiner and said second output.
Claim 11
Dependent Claim
241 words
Apparatus for generating digitized quadrature samples approximating the sampled complex envelopes of each of a plurality of input signals relative to a carrier frequency fc, comprising: a. means for receiving a plurality of input signals; b. signal sampler means for sampling each of said input signals at a periodic interval of T1, where T1 equals 1/(4fc), to obtain input signal samples of each of said input signals; c. analog-to-digital conversion means for converting said input signal samples to digital samples; and d. a digital system for processing said digital samples comprising: i. switching means having inputs to receive said digital samples and further having first, second, third and fourth terminals, said switching means operating to selectively communicate said digital samples to said terminals; ii. first and second outputs; iii. a first signal processor channel comprising a first combiner having a positive input connecting to said first terminal and further having a negative input, a first multiplier and first delay register connected in series between said second terminal and said negative input of said first combiner; and means for connecting said combiner to said first output; and iv. a second signal processor channel comprising a second combiner having a positive input and a negative input; a second multiplier connected between said third terminal and said positive input of said second combiner; a second delay register connected between said fourth terminal and said negative input of said second combiner and said second output.
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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |