US4600904A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Broken loop switched capacitor high pass filter
Assignee: Motorola Solutions Inc
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Filing: 1984-06-28
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Granted: 1986-07-15
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Expires: 2004-06-28
Abstract
Abstract A switched-capacitor high pass filter is disclosed and in which a switched capacitor approximation of an inductor is inserted in the direct coefficient loop to prevent instability. The value of the inductor is selected to compensate for the filter termination phase error.
Inventors
- 👤 Wayne G. Shumaker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:03
CPC Classifications
H; H03; H03H; H03H19/00; H03H19/004
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
223 words
A switched capacitor high pass filter having an input and an output, comprising: at least one high pass filter stage having at least two amplifiers, each amplifier having an input and an output port, said output port of a first amplifier coupled to said input port of a second amplifier via a first switched capacitor network and said output port of said second amplifier coupled to said input port of said first amplifier via a second switched capacitor network; an active output stage having an input and an output port, said output port coupled to the output of the switched capacitor filter; a first delay free coupling means from said output port of said first amplifier of said at least one high pass filter stage to said input port of said output stage, thereby creating a delay free coupling from said input port of said first amplifier to said output port of said output stage; a second delay free coupling means from said output port of said output stage to said input port of said second amplifier of said at least one high pass filter stage; and a switched capacitor inductor coupled between the input of the switched capacitor high pass filter and said input port of said first amplifier in a first one of said at least one high pass filter stage.
Claim 2
Dependent Claim
223 words
A switched capacitor high pass filter having an input and an output, comprising: at least one high pass filter stage having at least two amplifiers, each amplifier having an input and an output port, said output port of a first amplifier coupled to said input port of a second amplifier via a first switched capacitor network and said output port of said second amplifier coupled to said input port of said first amplifier via a second switched capacitor network; an active output stage having an input and an output port, said output port coupled to the output of the switched capacitor filter; a first delay free coupling means from said output port of said first amplifier of said at least one high pass filter stage to said input port of said output stage, thereby creating a delay free coupling from said input port of said first amplifier to said output port of said output stage; a second delay free coupling means from said output port of said output stage to said input port of said second amplifier of said at least one high pass filter stage; and a switched capacitor inductor coupled between the input of the switched capacitor high pass filter and said input port of said first amplifier in a first one of said at least one high pass filter stage.
Claim 3
Dependent Claim
21 words
A switched capacitor high pass filter in accordance with claim 1 wherein said switched capacitor inductor is a lossless discrete integrator.
References Cited (Backward Citations)
US1557036A
Cited
US1951025A
Cited
US3835399A
Cited
US4168440A
Cited
US4210872A
Cited
EP0015343A1
Cited
US4315229A
Cited
JPS5797715A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-14 | 1990-01-13 | 1990-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-14 | 1994-01-13 | 1994-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-14 | 1998-01-13 | 1998-07-15 | $7700.00 | Window Closed / Lapsed |