US4455539A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Switched capacitor all pass filter
Assignee: Motorola Solutions Inc
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Filing: 1982-08-13
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Granted: 1984-06-19
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Expires: 2002-08-13
Abstract
Abstract A switched capacitor all pass filter which provides an output signal having substantially linear magnitude and phase response is provided. A transfer function which represents an all pass filter and which has a predetermined phase response is provided. A filter/phase equalizer structure having integrating operational amplifiers and various feedback portions which represent the transfer function is also provided.
Inventors
- 👤 Henry Wurzburg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:12
CPC Classifications
H; H03; H03H; H03H19/00; H03H19/004
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
390 words
A switched capacitor all pass filter comprising: an input means coupled to an input terminal adapted to receive an analog voltage to be filtered, said input means comprising a first switched capacitor means; a first integrating operational amplifier having a first input terminal adapted to receive a reference voltage source, a second input terminal coupled to said input means, and an output terminal; a first feedback means comprising a first capacitor having a first electrode coupled to the second input terminal of said first integrating operational amplifier, and a second electrode coupled to the output terminal of said first integrating operational amplifier; a second switched capacitor means having an input terminal coupled to the output terminal of said first integrating operational amplifier, and an output terminal; a second integrating operational amplifier having a first input terminal adapted to receive said reference voltage source, a second input terminal coupled to the output terminal of said second switched capacitor means, and an output terminal for providing a filtered output signal; a second feedback means comprising a second capacitor having a first electrode coupled to the inverting input terminal of said second integrating operational amplifier, and a second electrode coupled to the output terminal of said second integrating operational amplifier; a third feedback means comprising a third capacitor having a first electrode coupled to the inverting input of said first integrating operational amplifier, and a second electrode coupled to the output of said second integrating operational amplifier; a fourth feedback means comprising a fourth capacitor having a first electrode coupled to said first switched capacitor means, and a second electrode alternately coupled between said reference voltage source and the output terminal of said second integrating operational amplifier; a fifth feedback means comprising a fifth capacitor having a first electrode coupled to said second switched capacitor means, and a second electrode alternately coupled between said reference voltage source and said input terminal; a sixth feedback means comprising a sixth capacitor having a first electrode coupled to said input terminal, and a second electrode coupled to the inverting input terminal of said second integrating operational amplifier; wherein the voltage from said input terminal is converted to a sampled data signal and an output voltage which contains all frequency components of the input voltage and which has a predetermined phase response for all frequencies is provided.
Claim 2
Dependent Claim
390 words
A switched capacitor all pass filter comprising: an input means coupled to an input terminal adapted to receive an analog voltage to be filtered, said input means comprising a first switched capacitor means; a first integrating operational amplifier having a first input terminal adapted to receive a reference voltage source, a second input terminal coupled to said input means, and an output terminal; a first feedback means comprising a first capacitor having a first electrode coupled to the second input terminal of said first integrating operational amplifier, and a second electrode coupled to the output terminal of said first integrating operational amplifier; a second switched capacitor means having an input terminal coupled to the output terminal of said first integrating operational amplifier, and an output terminal; a second integrating operational amplifier having a first input terminal adapted to receive said reference voltage source, a second input terminal coupled to the output terminal of said second switched capacitor means, and an output terminal for providing a filtered output signal; a second feedback means comprising a second capacitor having a first electrode coupled to the inverting input terminal of said second integrating operational amplifier, and a second electrode coupled to the output terminal of said second integrating operational amplifier; a third feedback means comprising a third capacitor having a first electrode coupled to the inverting input of said first integrating operational amplifier, and a second electrode coupled to the output of said second integrating operational amplifier; a fourth feedback means comprising a fourth capacitor having a first electrode coupled to said first switched capacitor means, and a second electrode alternately coupled between said reference voltage source and the output terminal of said second integrating operational amplifier; a fifth feedback means comprising a fifth capacitor having a first electrode coupled to said second switched capacitor means, and a second electrode alternately coupled between said reference voltage source and said input terminal; a sixth feedback means comprising a sixth capacitor having a first electrode coupled to said input terminal, and a second electrode coupled to the inverting input terminal of said second integrating operational amplifier; wherein the voltage from said input terminal is converted to a sampled data signal and an output voltage which contains all frequency components of the input voltage and which has a predetermined phase response for all frequencies is provided.
Claim 3
Dependent Claim
60 words
The switched capacitor all pass filter of claim 1 wherein said first and second switched capacitor means each comprise a capacitor having a first and a second plate, two switching devices driven by a first clock signal for coupling the first and second plates to said reference voltage source, and two additional switching devices driven by a second clock signal.
Claim 4
Dependent Claim
20 words
The switched capacitor all pass filter of claim 2 wherein said first and second clock signals are nonoverlapping complementary signals.
Claim 5
Dependent Claim
40 words
The switched capacitor all pass filter of claim 1 wherein the transfer function for the filter circuit is: ##EQU3## where K 1 , K 2 , K 3 , K 4 , K 5 and K 6 are predetermined constants.
Claim 6
Dependent Claim
243 words
A switched capacitor all pass filter having a substantially linear phase response and the following transfer function: ##EQU4## where K 1 , K 2 , K 3 , K 4 , K 5 and K 6 are predetermined constants, comprising: input means coupled to an input terminal adapted to receive an analog voltage to be filtered; a first integrating operational amplifier having a first input adapted to receive a reference voltage source, a second input coupled to said input means, and an output; first coupling means having a first terminal coupled to the output of the first integrating operational amplifier, and a second terminal; a second integrating operational amplifier having a first input adapted to receive the reference voltage source, a second input coupled to the second terminal of the first coupling means, and an output; second coupling means having a first terminal coupled to the output of the second integrating operational amplifier, and a second terminal coupled to the second input of the first integrating operational amplifier; and third coupling means having a first capacitor coupled between the second input of the second integrating operational amplifier and the input terminal, and a second capacitor having a first electrode selectively alternately coupled to the input terminal and the reference voltage source in response to first and second control signals, respectively, and a second electrode selectively coupled to the second input of the second integrating operational amplifier in response to the second control signal.
Claim 7
Dependent Claim
243 words
A switched capacitor all pass filter having a substantially linear phase response and the following transfer function: ##EQU4## where K 1 , K 2 , K 3 , K 4 , K 5 and K 6 are predetermined constants, comprising: input means coupled to an input terminal adapted to receive an analog voltage to be filtered; a first integrating operational amplifier having a first input adapted to receive a reference voltage source, a second input coupled to said input means, and an output; first coupling means having a first terminal coupled to the output of the first integrating operational amplifier, and a second terminal; a second integrating operational amplifier having a first input adapted to receive the reference voltage source, a second input coupled to the second terminal of the first coupling means, and an output; second coupling means having a first terminal coupled to the output of the second integrating operational amplifier, and a second terminal coupled to the second input of the first integrating operational amplifier; and third coupling means having a first capacitor coupled between the second input of the second integrating operational amplifier and the input terminal, and a second capacitor having a first electrode selectively alternately coupled to the input terminal and the reference voltage source in response to first and second control signals, respectively, and a second electrode selectively coupled to the second input of the second integrating operational amplifier in response to the second control signal.
Claim 8
Dependent Claim
167 words
The switched capacitor all pass filter of claim 5 wherein said input means comprise: a third capacitor having first and second electrodes; a first switch having a first terminal coupled to the input terminal, a second terminal coupled to the first electrode of the third capacitor, and a control electrode coupled to a first control signal; a second switch having a first terminal coupled to the first electrode of the third capacitor, a second terminal coupled to the reference voltage source, and a control terminal coupled to a second control signal; a third switch having a first terminal coupled to the second electrode of the third capacitor, a second terminal coupled to the reference voltage source, and a control terminal coupled to the second control signal; and a fourth switch having a first terminal coupled to the second electrode of the third capacitor, a second terminal coupled to the second input of the first integrating operational amplifier, and a control terminal coupled to the first control signal.
Claim 9
Dependent Claim
66 words
The switched capacitor filter of claim 5 wherein the first integrating operational amplifier comprises: an operational amplifier having an inverting input coupled to the input means, a noninverting input coupled to reference voltage source, and an output; and a third capacitor having a first electrode coupled to the inverting input of the operational amplifier, and a second electrode coupled to the output of the operational amplifier.
Claim 10
Dependent Claim
170 words
The switched capacitor filter of claim 5 wherein the first coupling means comprise: a third capacitor having first and second electrodes; a first switch having a first terminal coupled to the output of the first integrating operational amplifier, a second terminal coupled to the first electrode of the third capacitor, and a control terminal coupled to the first control signal; a second switch having a first terminal coupled to the first electrode of the capacitor, a second terminal coupled to the reference voltage source, and a control terminal coupled to the second control signal; a third switch having a first terminal coupled to the second electrode of the third capacitor, a second terminal coupled to the reference voltage source, and a control terminal coupled to the first control signal; and a fourth switch having a first terminal coupled to the second input of the second integrating operational amplifier, a second terminal coupled to the second electrode of the third capacitor, and a control terminal coupled to the second control signal.
Claim 11
Dependent Claim
74 words
The switched capacitor all pass filter of claim 5 wherein the second integrating operational amplifier comprises: an operational amplifier having an inverting input coupled to the second terminal of the first coupling means, a noninverting input coupled to the reference voltage source, and an output; and a third capacitor having a first electrode coupled to the inverting input of the operational amplifier, and a second electrode coupled to the output of the operational amplifier.
Claim 12
Dependent Claim
142 words
The switched capacitor all pass filter of claim 6 wherein the second coupling means comprise: a fourth capacitor having a first electrode coupled to the output of the second integrating operational amplifier, and a second electrode coupled to the second input of the first integrating operational amplifier; a fifth switch having a first terminal coupled to the output of the second integrating operational amplifier, a second terminal, and a control terminal coupled to the first control signal; a sixth switch having a first terminal coupled to the second terminal of the fifth switch, a second terminal coupled to the reference voltage source, and a control terminal coupled to the second control signal; and a fifth capacitor having a first electrode coupled to the second terminal of the fifth switch, and a second electrode coupled to the first terminal of the fourth switch.
References Cited (Backward Citations)
US4315227A
Cited
US4370632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |