US3621401A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency spectrum responsive noise reduction system
Assignee: Sierra Research Corp
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Filing: 1969-09-23
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Granted: 1971-11-16
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Expires: 1989-09-23
Abstract
Abstract A system for accepting signals of a desired frequency as well as undesired signals of other frequencies together therewith, separately examining the desired and undesired frequency components to determine their respective intensities and using the results of both determinations to control gating means in the main signal transferring path to pass signals whenever the respective levels of both the desired and the undesired signal components simultaneously fall within satisfactory ranges. These determination are made by regulating a composite of both signal components to a constant level, separating out both components, and then comparing the levels of each with preadjusted reference threshold levels to derive two simultaneous gate controlling signals.
Inventors
- 👤 Walter J Young Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:25
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/36; H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/344
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
261 words
A system having an input for accepting a spectrum of similarfrequency signals including on-frequency desired components and off-frequency undesired components and said system being operative to pass desired signal components having favorable levels to its output and to reduce interfering signals caused by undesired components by blocking the passage of signals to its output when the levels of desired and undesired signals relative to predetermined reference levels are unfavorable, comprising: a. main passband means coupled to said input to pass signals including desired components; b. gate means coupled between said main passband means and said output; c. auxiliary passband means coupled to said input to accept said desired and undesired components and deliver composite signals, said auxiliary passband means including first filter means connected to accept said composite signals and being frequencytuned to substantially block said desired components and to pass substantially the undesired components thereof and further including second filter means connected to accept said composite signals and frequency-tuned to pass substantially the desired component and to block the undesired components thereof, and said auxiliary passband means including separately adjustable reference level comparator means respectively coupled to said filter means to receive the components passed thereby and to compare their levels with predetermined reference means, the comparator means including means for delivering control signals to said gate means to render it conductive when the desired component levels and the undesired component levels are both favorable with respect to the respective predetermined reference means and to block the gate means when any of these component levels are unfavorable with respect thereto.
Claim 2
Independent Claim
261 words
A system having an input for accepting a spectrum of similarfrequency signals including on-frequency desired components and off-frequency undesired components and said system being operative to pass desired signal components having favorable levels to its output and to reduce interfering signals caused by undesired components by blocking the passage of signals to its output when the levels of desired and undesired signals relative to predetermined reference levels are unfavorable, comprising: a. main passband means coupled to said input to pass signals including desired components; b. gate means coupled between said main passband means and said output; c. auxiliary passband means coupled to said input to accept said desired and undesired components and deliver composite signals, said auxiliary passband means including first filter means connected to accept said composite signals and being frequencytuned to substantially block said desired components and to pass substantially the undesired components thereof and further including second filter means connected to accept said composite signals and frequency-tuned to pass substantially the desired component and to block the undesired components thereof, and said auxiliary passband means including separately adjustable reference level comparator means respectively coupled to said filter means to receive the components passed thereby and to compare their levels with predetermined reference means, the comparator means including means for delivering control signals to said gate means to render it conductive when the desired component levels and the undesired component levels are both favorable with respect to the respective predetermined reference means and to block the gate means when any of these component levels are unfavorable with respect thereto.
Claim 3
Dependent Claim
117 words
In a system as set forth in claim 1, said filter means delivering said components at separate filter outputs; and said comparator means comprising separate signal level comparators, each having its own adjustable reference level, and said comparators being respectively coupled to said filter outputs, each comparator having an output responsivE to the relative magnitude of the reference level and the component applied to that comparator; and said gate means having two control-signal inputs requiring simultaneous enabling to render the gate means conductive, one input partially enabling the gate when the undesired component level is below its comparator reference level, and the other input partially enabling the gate when the desired component exceeds its comparator reference level.
Claim 4
Dependent Claim
51 words
In a system as set forth in claim 1, said auxiliary passband means including regulating amplifier means for regulating said composite signals to a constant level to which said reference means are referred, and said amplifier means having a composite passband which is broad as compared with the main passband means.
Claim 5
Dependent Claim
61 words
In a system as set forth in claim 3, said predetermined reference means in the comparator means comprising means for establishing adjustable DC levels which are less than the peak level to which said regulating means adjusts the composite signal level, and means for comparing the instantaneous peak voltages of the components passed by the filter means with said DC levels.
Claim 6
Dependent Claim
89 words
In a system as set forth in claim 3, said first filter means in the auxiliary passband comprising a notch filter tuned to reject on-frequency components whereby its output comprises the off-frequency components of the regulated composite signal, and said comparator means including a first reference level to which the level of said off-frequency components is compared to obtain a gate control signal to block said gate means in the event that the former exceeds the latter and to partially enable the gate means when in the opposite event.
Claim 7
Dependent Claim
88 words
In a system as set forth in claim 5, said second filter means in the auxiliary passband comprising a pass filter tuned to pass on-frequency components whereby its output comprises the on-frequency components of the regulated composite signal, and said comparator means including a second reference level to which the level of said on-frequency components is compared to obtain a gate control signal to partially enable said gate means in the event that the former exceeds the latter and to block the gate means in the opposite event.
Claim 8
Independent Claim
138 words
The method of receiving and passing to an output desired signal components of one frequency and blocking spurious components of other frequencies which are also received in a spectrum therewith including the steps of: a. taking a portion of the received composite components and adjusting the level of said portion of the composite components to a standardized value; b. substantially separating said adjusted composite into said components; c. comparing the levels of the separated components with preselected reference levels whose magnitudes represent certain proportions of said standardized value to determine the levels of said components; and d. Selectively passing said received components to said output including blocking their passage whenever the desired components fall below a predetermined level or the spurious components exceed a predetermined level, and otherwise unblocking the passage to pass said components to the output.
Claim 9
Independent Claim
138 words
The method of receiving and passing to an output desired signal components of one frequency and blocking spurious components of other frequencies which are also received in a spectrum therewith including the steps of: a. taking a portion of the received composite components and adjusting the level of said portion of the composite components to a standardized value; b. substantially separating said adjusted composite into said components; c. comparing the levels of the separated components with preselected reference levels whose magnitudes represent certain proportions of said standardized value to determine the levels of said components; and d. Selectively passing said received components to said output including blocking their passage whenever the desired components fall below a predetermined level or the spurious components exceed a predetermined level, and otherwise unblocking the passage to pass said components to the 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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |