Patent US3796971A successfully refreshed from Google Patents.
US3796971A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-pass non-linear filter
Assignee: Individual
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Filing: 1971-10-21
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Granted: 1974-03-12
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Expires: 1991-10-21
Abstract
Abstract A non-linear filter for high and low frequency signals comprises means for separating and dissipating the high frequency out-ofband energy and passing the low frequency in-band energy. The filtering in a low-pass filter is achieved without phase shift both in- and out-of-band by use of conjugate high- and low-pass filters located before and after the dissipating means, respectively. A hard clipper is used to perform the dissipating function, and its reference clipping level is provided so that the maximum amplitude of the in-band signal arriving at the input to the clipper is slightly less than the clipping level. The output of the low-pass filter may be fed back to set the clipping level so that this level can track the in-band signal amplitude. A sensing resistor between the clipper and the means to set the clipping level senses the high frequency information and thus, the non-linear filter can serve as a high-pass filter with no phase shift when only the low-pass filter is used after the dissipating means.
Inventors
- 👤 S Sherman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:14
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/04; H03H11/0405
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
157 words
Apparatus for frequency separation of an electrical wave having low frequency and high frequency components comprising a clipper having an input, output and a level setting input, a high-pass filter having an input and an output, said input of said high-pass filter receiving said electrical wave, said output of said high-pass filter connected to said input of said clipper, a low-pass filter having an input and output, said input of said low-pass filter connected to the output of said clipper, a second amplifier means serving as an amplifier the output of said lowpass filter means being coupled through said second amplifier to said level setting input of said clipper means to instantaneously set said clipping level responsive to the magnitude of the low frequency components, said clipping level comprising a fixed bias level and superimposed thereon the low frequency components produced at the output of said low-pass filter means, and said high-pass and low-pass filters being conjugate.
Claim 2
Dependent Claim
157 words
Apparatus for frequency separation of an electrical wave having low frequency and high frequency components comprising a clipper having an input, output and a level setting input, a high-pass filter having an input and an output, said input of said high-pass filter receiving said electrical wave, said output of said high-pass filter connected to said input of said clipper, a low-pass filter having an input and output, said input of said low-pass filter connected to the output of said clipper, a second amplifier means serving as an amplifier the output of said lowpass filter means being coupled through said second amplifier to said level setting input of said clipper means to instantaneously set said clipping level responsive to the magnitude of the low frequency components, said clipping level comprising a fixed bias level and superimposed thereon the low frequency components produced at the output of said low-pass filter means, and said high-pass and low-pass filters being conjugate.
Claim 3
Dependent Claim
69 words
Apparatus as set forth in claim 1, comprising first, and third amplifier means each having an input and an output, said input of said third amplifier means being connected to the output of said high-pass filter, said output of said third amplifier means being connected to said input of said clipper, said output of said clipper being connected through said first amplifier to said input of said low-pass filter.
Claim 4
Dependent Claim
20 words
Apparatus as set forth in claim 2, wherein said first, second and third amplifier means operate in their linear modes.
Claim 5
Dependent Claim
18 words
Apparatus as set forth in claim 2, wherein said first, second and third amplifier means are wideband amplifiers.
Claim 6
Dependent Claim
15 words
Apparatus as set forth in claim 2, wherein said low-pass and high-pass filters are conjugate.
Claim 7
Dependent Claim
18 words
Apparatus as set forth in claim 2, wherein said first and second amplifier means have low output impedances.
Claim 8
Dependent Claim
14 words
Apparatus as set forth in claim 2, wherein said clipper is a hard clipper.
Claim 9
Dependent Claim
30 words
Apparatus as set forth in claim 2, wherein the combined amplitude gain between the output of the clipper and the level setting input of said clipper is less than unity.
Claim 10
Dependent Claim
23 words
Apparatus as set forth in claim 1, comprising current sensing resistor means connected to said dissipating means for sensing the high frequency components.
Claim 11
Dependent Claim
56 words
Apparatus as set forth in claim 9, comprising first amplifier means having an input and output, said output of said clipper means connected to said low-pass filter means through said first amplifier means, said output of said second amplifier means being connected to said level sensing input of said clipper through said current sensing resistor means.
Claim 12
Dependent Claim
18 words
Apparatus as set forth in claim 10, wherein said first and second amplifier means have low output impedances.
Claim 13
Dependent Claim
26 words
Apparatus as set forth in claim 10, comprising a high-pass filter with said electrical wave connected to said input of said clipper through said high-pass filter.
Claim 14
Dependent Claim
88 words
For an electrical wave having low frequency and high frequency components, a method of separating said components comprising the steps of controlling a clipping level, clipping said high frequency components while passing said low frequency components, emphasizing said passed low frequency components with respect to any passed high frequency components, and instantaneously tracking said emphasized, passed low frequency components with said clipping level to instanteously set the clipping level in response to the magnitude of low frequency components for separating said high frequency from said low frequency components.
Claim 15
Dependent Claim
88 words
For an electrical wave having low frequency and high frequency components, a method of separating said components comprising the steps of controlling a clipping level, clipping said high frequency components while passing said low frequency components, emphasizing said passed low frequency components with respect to any passed high frequency components, and instantaneously tracking said emphasized, passed low frequency components with said clipping level to instanteously set the clipping level in response to the magnitude of low frequency components for separating said high frequency from said low frequency components.
Claim 16
Dependent Claim
21 words
A method as set forth in claim 13, comprising the step of sensing said high frequency components aFter said clipping step.
Claim 17
Dependent Claim
22 words
A method as set forth in claim 13, comprising the step of emphasizing said high frequency components prior to said clipping step.
Claim 18
Dependent Claim
42 words
A method as set forth in claim 15, comprising the steps of phase shifting said electrical wave equal and opposite amounts during said steps of emphasizing said high frequency components and emphasizing said passed low frequency components to achieve zero phase shift.
Claim 19
Dependent Claim
21 words
A method as set forth in claim 16, comprising the step of sensing said high frequency components after said clipping step.
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) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |