Patent US3614640A successfully refreshed from Google Patents.
US3614640A
Expired / Lapsed
US
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Frequency discriminator using no inductive components
Assignee: United States Department of the Navy
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Filing: 1970-01-27
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Granted: 1971-10-19
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Expires: 1990-01-27
Abstract
Abstract A frequency discriminator which is mechanized of active filters and operational amplifiers. The signal under test is simultaneously applied to a plus detector channel and a minus detector cannel these channels having active filters of band-pass configuration, one with a center frequency below the discriminator frequency and one above. The channels also have operational amplifier type detectors and the outputs of the two channels are combined, post detection filtering being accomplished by a summing amplifier by virtue of a RC feedback applied around this amplifier.
Inventors
- 👤 Frederick H Wolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:48
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/06; H03D3/28
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
120 words
A frequency discriminator comprising: means for receiving an input signal whose frequency is being tested; a positive detector channel; a negative detector channel; means for applying the input signal to both the positive and the negative detector channels; inductorless frequency selection means in each detector channel including an active filter; detector means in each detector channel including an operational amplifier, a full wave rectifier, and temperature stabilization means; said temperature stabilization means includes a resistor feedback from the output of the full wave rectifier to the input of said operational amplifier; and means for summing the output of the detector channels including a passive filter and an operational amplifier connected in parallel, wherein the passive filter is an RC circuit.
Claim 2
Dependent Claim
120 words
A frequency discriminator comprising: means for receiving an input signal whose frequency is being tested; a positive detector channel; a negative detector channel; means for applying the input signal to both the positive and the negative detector channels; inductorless frequency selection means in each detector channel including an active filter; detector means in each detector channel including an operational amplifier, a full wave rectifier, and temperature stabilization means; said temperature stabilization means includes a resistor feedback from the output of the full wave rectifier to the input of said operational amplifier; and means for summing the output of the detector channels including a passive filter and an operational amplifier connected in parallel, wherein the passive filter is an RC circuit.
Claim 3
Dependent Claim
24 words
The device of claim 1 wherein the positive channel active filter has a bandpass configuration with a center frequency above the desired discriminator frequency.
Claim 4
Dependent Claim
24 words
The device of claim 2 wherein the negative channel active filter has a bandpass configuration with a center frequency below the desired discriminator frequency.
Claim 5
Dependent Claim
49 words
The device of claim 1 wherein said active filter includes means for varying the center frequency of the active filter without affecting the bandwidth or the gain thereof comprising a variable resistor connected between the capacitive input to the amplifier of the active filter and a suitable reference potential.
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) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |