US3639739A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital low pass filter
Assignee: Boeing North American Inc
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Filing: 1969-02-05
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Granted: 1972-02-01
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Expires: 1989-02-05
Abstract
Abstract Means for low-pass filtering sampled digital data comprising a recirculating accumulator operated at a preselected sampling rate and having an output; and comparator means having a first sampling input coupled to an output of said accumulator and further having a second sampling input adapted to be connected to a digital signal to be filtered, an output of said comparator means being fed to an input of said accumulator, and the sampling rate of said first input of said comparator being substantially slower than that of said second input. The low relative sampling rate of the feedback arrangement serves to reduce the band-pass of the low-pass filter, while selective variation of such sampling rate correspondingly varies such band-pass.
Inventors
- 👤 Roger M Golden
- 👤 Stanley A White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:02
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/04; H03H17/0416
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
110 words
In a sampled data systems having a preselected system sampling interval (T), means for adjustably low-pass filtering sampled data comprising a recirculating accumulator operated at a preselected worddelay; comparator means having a first sampling input coupled to an output of said accumulator and further having a second sampling input adapted to be coupled to a source of a digital signal to be filtered, an output of said comparator means being fed to an input of said accumulator, and a preselected one of the sampling interval of said first input of said comparator and the delay of said accumulator being selectively adjustable integer multiple (k) of said system sampling interval (T).
Claim 2
Dependent Claim
110 words
In a sampled data systems having a preselected system sampling interval (T), means for adjustably low-pass filtering sampled data comprising a recirculating accumulator operated at a preselected worddelay; comparator means having a first sampling input coupled to an output of said accumulator and further having a second sampling input adapted to be coupled to a source of a digital signal to be filtered, an output of said comparator means being fed to an input of said accumulator, and a preselected one of the sampling interval of said first input of said comparator and the delay of said accumulator being selectively adjustable integer multiple (k) of said system sampling interval (T).
Claim 3
Dependent Claim
94 words
The device of claim 1 in which said accumulator comprises a multiword time delay (kT) element, and in which there is further provided signal-combining means responsively coupled to said output of said accumulator, a like second multiword delay element responsively coupled to said output of said accumulator and cooperating with said signal-combining means as a digital differentiator; a single-word delay element input coupled to an output of said signal combining means and further cooperating therewith as a second recirculating accumulator, an output of said second recirculating accumulator representing a low-pass filtered output of interest.
Claim 4
Dependent Claim
77 words
The device of claim 1 in which said accumulator comprises a multiword time delay (kT) element and in which there is further provided signal-combining means responsively coupled to a second output of said accumulator and cooperating therewith as a digital differentiator; a single-word delay element input coupled to an output of said signal-combining means and further cooperating therewith as a second recirculating accumulator, an output of said second recirculating accumulator representing a low-pass filtered output of interest.
Claim 5
Dependent Claim
65 words
In a digital sample data system, low-pass digital filter means comprising a recirculating accumulator having an output; and comparator means having a first input of adjustable sampling rate and responsive to said output of said accumulator and further having a second input adapted to be responsive to a sampled digital signal, an input of said accumulator being responsive to an output of said comparison means.
Claim 6
Dependent Claim
65 words
In a digital sample data system, low-pass digital filter means comprising a recirculating accumulator having an output; and comparator means having a first input of adjustable sampling rate and responsive to said output of said accumulator and further having a second input adapted to be responsive to a sampled digital signal, an input of said accumulator being responsive to an output of said comparison means.
Claim 7
Dependent Claim
94 words
Means for adjustable low-pass filtering sampled digital data comprising a recirculating accumulator operated at a preselected sampling rate and having an output; and comparator means having a first sampling input coupled to an output of said accumulator and further having a second sampling input adapted to be connected to a source of a digital signal to be filtered, an output of said comparator means being fed to an input of said accumulator, and the sampling rate of said second input of said comparator being selectively adjustable substantially slower than that of said first input.
Claim 8
Dependent Claim
94 words
Means for adjustable low-pass filtering sampled digital data comprising a recirculating accumulator operated at a preselected sampling rate and having an output; and comparator means having a first sampling input coupled to an output of said accumulator and further having a second sampling input adapted to be connected to a source of a digital signal to be filtered, an output of said comparator means being fed to an input of said accumulator, and the sampling rate of said second input of said comparator being selectively adjustable substantially slower than that of said first input.
Claim 9
Dependent Claim
24 words
The device of claim 5 in which the sampling rates of said accumulator and said first input of said comparator means are mutually synchronous.
Claim 10
Dependent Claim
35 words
The device of claim 5 in which there is further provided means for adjusting the sampling rate of said second input of said comparator, whereby the low-pass bandwidth of said means for filtering is varied.
Claim 11
Dependent Claim
90 words
In a digital sampled data system, low-pass digital filter means comprising comparator means having a first and second sampled input, the samplIng rate of said second input being selectively adjustable and substantially less than that of said first input; an adder having a first input responsively coupled to an output of said comparator means and further having a second input; a delay means having an input coupled to an output of said adder and having an output fed to a respective second input of each of said comparator and adder.
Claim 12
Dependent Claim
90 words
In a digital sampled data system, low-pass digital filter means comprising comparator means having a first and second sampled input, the samplIng rate of said second input being selectively adjustable and substantially less than that of said first input; an adder having a first input responsively coupled to an output of said comparator means and further having a second input; a delay means having an input coupled to an output of said adder and having an output fed to a respective second input of each of said comparator and adder.
Claim 13
Dependent Claim
47 words
The device of claim 8 in which there is further provided means operated in synchronism with said selectively adjustable sampling rate and coupled to said output of said adder for providing a low-pass filtered output having a gain compensatorily adjusted for changes in said adjustable sampling rate.
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) | 1975-01-31 | 1975-08-02 | 1976-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-31 | 1979-08-02 | 1980-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-31 | 1983-08-02 | 1984-02-01 | $7700.00 | Window Closed / Lapsed |