US3636446A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Receiver for detecting signals within a predetermined bandwidth
Assignee: H B Engineering Corp
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Filing: 1970-03-04
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Granted: 1972-01-18
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Expires: 1990-03-04
Abstract
Abstract A receiver for detecting the presence of a signal, said receiver including a first multiplier for multiplying together the signal to be detected and a signal at substantially the same frequency as the signal to be detected, a second multiplier for multiplying together the signal to be detected and a signal at substantially the same frequency as the signal to be detected, said signals provided to the second multiplier being separated by about 90* by phase-shifting means, low-pass filters coupled to the output of each of the multipliers and a detector for combining the signals from the filters and sensing if the combined level thereof is greater or equal to a predetermined level.
Inventors
- 👤 Roland E Genter
- 👤 Raymond S Connell Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:08
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/12; G08B; G08B25/00; G08B25/01; G08B25/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
248 words
A receiver for detecting the presence of a sinusoidal input signal within a predetermined bandwidth comprising means for generating a sinusoidal reference signal of approximately the same frequency as the signal to be detected, first multiplier means for multiplying together the input signal and the reference signal, means for phase shifting one or both of said signals such that about a 90* phase difference is provided between said signals, second multiplier means for multiplying together said signals that have been phase shifted relative to each other, first and second low-pass filter means for filtering out a lowfrequency envelope indicative of the presence of an input signal at the output of each of said filters, said first filter coupled to the output of said first multiplIer and said second filter coupled to the output of said second multiplier, first and second absolute value means for providing output signals representing the absolute value of the output signals from said filters, said first absolute value means coupled to the output of said first filter, and said second absolute value means coupled to the output of said second filter, summing means coupled to the output of said first and second absolute value means for providing a signal representing the sum of the absolute signal values, and level detection means coupled to said summing means for providing an output signal level of a predetermined magnitude if the sum of the absolute signal values is greater than or equal to a predetermined reference value.
Claim 2
Dependent Claim
248 words
A receiver for detecting the presence of a sinusoidal input signal within a predetermined bandwidth comprising means for generating a sinusoidal reference signal of approximately the same frequency as the signal to be detected, first multiplier means for multiplying together the input signal and the reference signal, means for phase shifting one or both of said signals such that about a 90* phase difference is provided between said signals, second multiplier means for multiplying together said signals that have been phase shifted relative to each other, first and second low-pass filter means for filtering out a lowfrequency envelope indicative of the presence of an input signal at the output of each of said filters, said first filter coupled to the output of said first multiplIer and said second filter coupled to the output of said second multiplier, first and second absolute value means for providing output signals representing the absolute value of the output signals from said filters, said first absolute value means coupled to the output of said first filter, and said second absolute value means coupled to the output of said second filter, summing means coupled to the output of said first and second absolute value means for providing a signal representing the sum of the absolute signal values, and level detection means coupled to said summing means for providing an output signal level of a predetermined magnitude if the sum of the absolute signal values is greater than or equal to a predetermined reference value.
Claim 3
Dependent Claim
36 words
A receiver according to claim 1 in which the reference signal establishes the center frequency of the receivers'' band-pass characteristic and wherein the bandwidth of the receiver is approximately equal to twice the low-pass filter bandwidth.
Claim 4
Dependent Claim
25 words
A receiver according to claim 2 in which an indicator is coupled to the level detection means to indicate the presence of an input signal.
Claim 5
Dependent Claim
18 words
A receiver according to claim 1 in which each of the absolute value means comprises a full-wave rectifier.
Claim 6
Dependent Claim
212 words
A receiver for detecting the presence of a sinusoidal input signal within a predetermined bandwidth comprising means for generating a sinusoidal reference signal of approximately the same frequency as the signal to be detected, first multiplier means for multiplying together the input signal and the reference signal, means for phase shifting one or both of said signals such that about a 90* phase difference is provided between said signals, second multiplier means for multiplying together said signals that have been phase shifted relative to each other, first and second low-pass filter means for filtering out a low-frequency envelope indicative of the presence of an input signal at the output of each of said filters, said first filter coupled to the output of said first multiplier and said second filter coupled to the output of said second multiplier, first squaring means coupled to the output of said first filter for squaring the output signal from said first filter, second squaring means coupled to the output of said second filter for squaring the output signal from said second filter, summing means coupled to the output of said first and second squaring means, and detection means for generating a predetermined output signal level depending upon the magnitude of the signal provided by said summing means.
Claim 7
Dependent Claim
212 words
A receiver for detecting the presence of a sinusoidal input signal within a predetermined bandwidth comprising means for generating a sinusoidal reference signal of approximately the same frequency as the signal to be detected, first multiplier means for multiplying together the input signal and the reference signal, means for phase shifting one or both of said signals such that about a 90* phase difference is provided between said signals, second multiplier means for multiplying together said signals that have been phase shifted relative to each other, first and second low-pass filter means for filtering out a low-frequency envelope indicative of the presence of an input signal at the output of each of said filters, said first filter coupled to the output of said first multiplier and said second filter coupled to the output of said second multiplier, first squaring means coupled to the output of said first filter for squaring the output signal from said first filter, second squaring means coupled to the output of said second filter for squaring the output signal from said second filter, summing means coupled to the output of said first and second squaring means, and detection means for generating a predetermined output signal level depending upon the magnitude of the signal provided by said summing means.
Claim 8
Dependent Claim
34 words
A system according to claim 5 in which the detection means includes means coupled to the summing means for taking the square root of the signal provided at the output of the summing means.
Claim 9
Dependent Claim
37 words
A system according to claim 6 in which the detection means includes level detector means for indicating if the output from the means for taking the square root is greater than or equal to a predetermined level.
Claim 10
Dependent Claim
24 words
A system according to claim 7 in which the detection means includes utilization means responsive to a signal provided by said level detector means.
Claim 11
Independent Claim
125 words
A method of detecting the presence of an input signal of a predetermined frequency which comprises the steps of (a) multiplying together a reference signal of the same frequency as the input signal to be detected with the input signal, (b) phase shifting the input signal and said reference signal relative to each other to provide about a 90* degree phase difference between the signals, (c) multiplying together the input and said reference signals after they have been phase shifted with respect to each other, (d) low-pass filtering the products of both multiplication steps, and (e) generating a steady DC voltage level if the sum of the products of the signals provided after low-pass filtering is equal to or greater than a predetermined threshold voltage.
Claim 12
Independent Claim
125 words
A method of detecting the presence of an input signal of a predetermined frequency which comprises the steps of (a) multiplying together a reference signal of the same frequency as the input signal to be detected with the input signal, (b) phase shifting the input signal and said reference signal relative to each other to provide about a 90* degree phase difference between the signals, (c) multiplying together the input and said reference signals after they have been phase shifted with respect to each other, (d) low-pass filtering the products of both multiplication steps, and (e) generating a steady DC voltage level if the sum of the products of the signals provided after low-pass filtering is equal to or greater than a predetermined threshold voltage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |