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US4232279A
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Low noise charge coupled device transversal filter
Assignee: Raytheon Co
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Filing: 1978-11-15
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Granted: 1980-11-04
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Expires: 1998-11-15
Abstract
Abstract A charge coupled device (CCD) transversal filter (TVF) having an improved electrode configuration and connecting arrangement which minimizes the noise that is added to the signal to provide a relatively high amplitude output signal and a relatively high output signal-to-noise ratio. The CCD transversal filter operates with the weighting coefficients determined by the one sided width of the electrodes and with one end of the split electrodes coupled to the output and the other ends of the split electrodes coupled to a reference voltage source. When some of the weighting coefficients of the desired impulse response are negative the output ends of the weighting electrodes are selectively connected to either the inverting or noninverting common connections of a differential amplifier in turn providing the transversal filter output signals. For a single polarity impulse response, all of the electrodes are coupled to an output arrangement without requiring an inversion. In the one sided transversal filter of the invention the net output signal in terms of charge is the same as for a conventional two-sided transversal filter but the electrode area contributing noise is substantially less than in the conventional two-sided arrangement. As the noise charge generated within a bucket is transferred down the channel, it becomes coherent from side to side and the charge added to the signal and sensed on the following electrodes is not reduced in the system of the invention. Because the total electrode capacitance is a function of total electrode area the system provides a significant increase in voltage swing at the output and has a further advantage that the effect of the input noise of the output differential amplifier is also significantly reduced because of the relatively large signal.
Inventors
- 👤 Paul R. Prince
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:42
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; G; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C19/00; G11C19/28; H03; H03H; H03H15/00; H03H15/02; H03H7/00; H03H7/30
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
92 words
A CCD transversal filter comprising: a substrate having first and second ends, a plurality of weighting electrodes positioned along said substrate between the first and second ends, each electrode split into first and second portions, said electrodes having a split configuration to provide a selected filter characteristic, a constant voltage bias source coupled to the first portion of each of said split electrodes, first and second output leads selectively coupled to the second portion of each of said split electrodes, and a differential amplifier coupled to said first and second output leads.
Claim 2
Dependent Claim
92 words
A CCD transversal filter comprising: a substrate having first and second ends, a plurality of weighting electrodes positioned along said substrate between the first and second ends, each electrode split into first and second portions, said electrodes having a split configuration to provide a selected filter characteristic, a constant voltage bias source coupled to the first portion of each of said split electrodes, first and second output leads selectively coupled to the second portion of each of said split electrodes, and a differential amplifier coupled to said first and second output leads.
Claim 3
Dependent Claim
38 words
The combination of claim 1 further including electrode means adjacent to each split electrode for transferring charges between split electrodes and clock means coupled to said electrode means for controlling the transfer of charges between adjacent split electrodes.
Claim 4
Dependent Claim
38 words
The combination of claim 1 further comprising sample and hold means including first and second pentodes having first terminals respectively coupled to said first and second output leads and having second terminals coupled to said differential amplifier means.
Claim 5
Dependent Claim
17 words
The combination of claim 2 further including reset means coupled to said first and second output leads.
Claim 6
Dependent Claim
138 words
A charge coupled transversal filter for providing a desired impulse response having a first and second polarity comprising a substrate, a plurality of split weighting electrodes positioned along said substrate adjacent to each other, each split electrode having an insulating gap between first and second portions thereof, said gaps having a configuration of said impulse response with the split electrodes representative of the first polarity response having an inverted configuration and the electrodes representative of the second polarity having a noninverted configuration, a source of reference potential coupled to the first portions of said split electrodes, first and second output leads respectively coupled to the second portions of said inverted and noninverted split electrodes, and combining means coupled to said first and second output leads for inverting the signal received from said split electrodes having the inverted configuration.
Claim 7
Dependent Claim
138 words
A charge coupled transversal filter for providing a desired impulse response having a first and second polarity comprising a substrate, a plurality of split weighting electrodes positioned along said substrate adjacent to each other, each split electrode having an insulating gap between first and second portions thereof, said gaps having a configuration of said impulse response with the split electrodes representative of the first polarity response having an inverted configuration and the electrodes representative of the second polarity having a noninverted configuration, a source of reference potential coupled to the first portions of said split electrodes, first and second output leads respectively coupled to the second portions of said inverted and noninverted split electrodes, and combining means coupled to said first and second output leads for inverting the signal received from said split electrodes having the inverted configuration.
Claim 8
Dependent Claim
156 words
A charge coupled transversal filter for providing a selected impulse response having first and second polarity portions, said impulse response being defined by a plurality of weighting coefficients of first and second polarities, comprising a substrate, a plurality of weighting electrodes positioned adjacent to each other and along said substrate, each weighting electrode having first and second portions split with an insulating gap, each of said second portions having a length proportional to one of said weighting coefficients, said electrodes corresponding to coefficients of a second polarity having gaps forming an inverted configuration of said impulse response, reference means coupled to the first portions of said split electrodes, first and second leads coupled to the second portions representing respective first and second polarity weighting coefficients, for respectively forming the first and second polarity portions of said impulse response, and combining means coupled to said first and second leads for inverting the signal on said second lead.
Claim 9
Dependent Claim
156 words
A charge coupled transversal filter for providing a selected impulse response having first and second polarity portions, said impulse response being defined by a plurality of weighting coefficients of first and second polarities, comprising a substrate, a plurality of weighting electrodes positioned adjacent to each other and along said substrate, each weighting electrode having first and second portions split with an insulating gap, each of said second portions having a length proportional to one of said weighting coefficients, said electrodes corresponding to coefficients of a second polarity having gaps forming an inverted configuration of said impulse response, reference means coupled to the first portions of said split electrodes, first and second leads coupled to the second portions representing respective first and second polarity weighting coefficients, for respectively forming the first and second polarity portions of said impulse response, and combining means coupled to said first and second leads for inverting the signal on said second lead.
Claim 10
Dependent Claim
146 words
A CCD transversal filter having a selected impulse response formable from a plurality of first and second polarity weighting coefficients comprising a substrate, a plurality of split weighting electrodes positioned on said substrate for each providing a first plurality weighting coefficient of the selected impulse response, each split electrode having first and second ends, a source of a reference potential coupled to the first ends of said split electrodes, a first output lead coupled to the second ends of the weighting electrodes corresponding to the first polarity weighting coefficients of said impulse response, a second output lead coupled to the second ends of the weighting electrodes corresponding to the second polarity weighting coefficients of said impulse response, and combining means coupled to the first and second output leads for inverting the signal in said second lead and combining with the signals on said first output lead.
Claim 11
Dependent Claim
146 words
A CCD transversal filter having a selected impulse response formable from a plurality of first and second polarity weighting coefficients comprising a substrate, a plurality of split weighting electrodes positioned on said substrate for each providing a first plurality weighting coefficient of the selected impulse response, each split electrode having first and second ends, a source of a reference potential coupled to the first ends of said split electrodes, a first output lead coupled to the second ends of the weighting electrodes corresponding to the first polarity weighting coefficients of said impulse response, a second output lead coupled to the second ends of the weighting electrodes corresponding to the second polarity weighting coefficients of said impulse response, and combining means coupled to the first and second output leads for inverting the signal in said second lead and combining with the signals on said first output lead.
Claim 12
Dependent Claim
35 words
The combination of claim 7 further including a source of clock pulses and means positioned at each split weighting electrode and coupled to said source of clock pulses for transferring charges between split weighting electrodes.
Claim 13
Dependent Claim
30 words
The combination of claim 8 further including switching means coupled to said first and second output leads for establishing a reference voltage on said split electrodes between said clock pulses.
Claim 14
Dependent Claim
168 words
A CCD transversal filter operable to develop a selected impulse response from a plurality of predetermined weighting coefficients being of both first and second polarities comprising a plurality of split weighting electrodes each having a portion with an upper width and a portion with a lower width, said lower width of each weighting electrode defining a weighting coefficient of a first polarity, a group of transfer electrodes positioned adjacent to each split electrode, clock means coupled to each group of transfer electrodes for transferring charges between said split electrodes, reference means coupled to the portion of said split weighting electrodes with an upper width, first and second output leads respectively coupled to the portion of said split electrodes with a lower width representing a weighting coefficient with said first polarity and coupled to the portion of said split electrodes with a lower width representing a weighting coefficient with said second polarity, and combining means having inverting and noninverting inputs respectively coupled to said first and second output leads.
Claim 15
Dependent Claim
168 words
A CCD transversal filter operable to develop a selected impulse response from a plurality of predetermined weighting coefficients being of both first and second polarities comprising a plurality of split weighting electrodes each having a portion with an upper width and a portion with a lower width, said lower width of each weighting electrode defining a weighting coefficient of a first polarity, a group of transfer electrodes positioned adjacent to each split electrode, clock means coupled to each group of transfer electrodes for transferring charges between said split electrodes, reference means coupled to the portion of said split weighting electrodes with an upper width, first and second output leads respectively coupled to the portion of said split electrodes with a lower width representing a weighting coefficient with said first polarity and coupled to the portion of said split electrodes with a lower width representing a weighting coefficient with said second polarity, and combining means having inverting and noninverting inputs respectively coupled to said first and second output leads.
Claim 16
Dependent Claim
159 words
A CCD transversal filter to provide a selected impulse response to input charges and defined by a plurality of time sequential weighting coefficients being both positive and negative comprising a substrate, a plurality of split electrodes positioned along said substrate and having first and second portions, said second portions each having a surface area representative of a weighting coefficient, said second portions of said plurality of split electrodes having surface areas selected along said substrate to provide said time sequential weighting coefficients, a source of reference potential coupled to the first portions of said split electrodes, first and second output conductors respectively coupled to the second portions of said split electrodes corresponding to the weighting coefficients of the first polarity and coupled to the second portions of said split electrodes corresponding to the weighting coefficients of the second polarity, and combining means having an inverting and a noninverting input terminal respectively coupled to said first and second output conductors.
Claim 17
Dependent Claim
159 words
A CCD transversal filter to provide a selected impulse response to input charges and defined by a plurality of time sequential weighting coefficients being both positive and negative comprising a substrate, a plurality of split electrodes positioned along said substrate and having first and second portions, said second portions each having a surface area representative of a weighting coefficient, said second portions of said plurality of split electrodes having surface areas selected along said substrate to provide said time sequential weighting coefficients, a source of reference potential coupled to the first portions of said split electrodes, first and second output conductors respectively coupled to the second portions of said split electrodes corresponding to the weighting coefficients of the first polarity and coupled to the second portions of said split electrodes corresponding to the weighting coefficients of the second polarity, and combining means having an inverting and a noninverting input terminal respectively coupled to said first and second output conductors.
Claim 18
Dependent Claim
47 words
The combination of claim 11 further including clock means, transfer electrode means adjacent to each split electrode and coupled to said clock means for transferring stored charges therebetween, and reset means coupled to said first and second output conductors for establishing reference charges on said split conductors.
Claim 19
Dependent Claim
134 words
A CCD transversal filter having a characteristic to provide a selected impulse response defined by a plurality of weighting coefficients comprising: a substrate having first and second ends, a plurality of split weighting electrodes positioned along said substrate between said first and second ends, said split weighting electrodes each having a gap between first and second portions to provide one of said weighting coefficients as a function of the length of said second portion, a reference potential coupled to the first portion of each of said split weighting electrodes, signal combining means coupled to the second portion of each of said split weighting electrodes, and sample and hold means including first and second pentodes coupled between the second portions of said split weighting electrodes and said means for coupling all of said second portions.
Claim 20
Dependent Claim
134 words
A CCD transversal filter having a characteristic to provide a selected impulse response defined by a plurality of weighting coefficients comprising: a substrate having first and second ends, a plurality of split weighting electrodes positioned along said substrate between said first and second ends, said split weighting electrodes each having a gap between first and second portions to provide one of said weighting coefficients as a function of the length of said second portion, a reference potential coupled to the first portion of each of said split weighting electrodes, signal combining means coupled to the second portion of each of said split weighting electrodes, and sample and hold means including first and second pentodes coupled between the second portions of said split weighting electrodes and said means for coupling all of said second portions.
Claim 21
Dependent Claim
94 words
A CCD transversal filter comprising: a substrate having first and second ends; a plurality of weighting electrodes positioned along said substrate between the first and second ends, each of said weighting electrodes split into first and second portions, said weighting electrodes having the split configuration to provide a selected filter characteristic; a constant voltage bias source coupled to a first portion of each of said split electrodes; a plurality of output leads selectively coupled to the second portion of each of said split electrodes; and combining means coupled to said plurality of output leads.
Claim 22
Dependent Claim
94 words
A CCD transversal filter comprising: a substrate having first and second ends; a plurality of weighting electrodes positioned along said substrate between the first and second ends, each of said weighting electrodes split into first and second portions, said weighting electrodes having the split configuration to provide a selected filter characteristic; a constant voltage bias source coupled to a first portion of each of said split electrodes; a plurality of output leads selectively coupled to the second portion of each of said split electrodes; and combining means coupled to said plurality of output leads.
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) | 1983-11-04 | 1984-05-05 | 1984-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-04 | 1988-05-05 | 1988-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-04 | 1992-05-05 | 1992-11-04 | $7700.00 | Window Closed / Lapsed |