US3634843A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit and method for detecting localized noise level changes and especially electromagnetic noise
Assignee: PRODUCT DEV SERVICES Inc
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Filing: 1968-10-14
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Granted: 1972-01-11
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Expires: 1988-10-14
Abstract
Abstract A detection circuit responsive to a localized increase in magnetic noise level such as would be produced by an automobile ignition system. Sensing coils are positioned to detect the presence of such noise and provide an electrical output. The electrical output of the sensing coils is amplified and passed to networks having differing time constants. Both networks feed into a comparator which, in turn, actuates an alarm. The comparator actuates the alarm only when it receives signals of different intensities. Thus the two networks function to provide a threshold for the signaling device which is automatically reset as required.
Inventors
- 👤 Charles J Corris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:41
CPC Classifications
G; G08; G08G; G08G1/00; G08G1/01
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
227 words
A detection circuit responsive to a change in noise level in one portion of a surveillance region which comprises: a plurality of sensing element means within said region, each of said sensing element means being adapted to produce an electrical output in response to detected noise; a first network having a relatively short time constant connected to receive the electrical output of said sensing element means and producing a first output signal responsive thereto, said first network being quickly responsive to changes in said detected noise by virtue of said short time constant rendering said first output signal representative of sudden changes in said detected noise; a second network having a relatively long time constant connected to receive the electrical output of said sensing element means and producing a second output signal responsive thereto, said second network being slowly responsive to changes in said detected noise by virtue of said long time constant rendering said second output signal representative of a continuously readjusted ambient level of detected noise; comparator means connected to receive said first and second output signals of said first and second networks for producing a signal only when said first output signal is greater than said second output signal; and alarm means actuated by said signal for providing an alarm indication only when said first output signal is greater than said second output signal.
Claim 2
Dependent Claim
227 words
A detection circuit responsive to a change in noise level in one portion of a surveillance region which comprises: a plurality of sensing element means within said region, each of said sensing element means being adapted to produce an electrical output in response to detected noise; a first network having a relatively short time constant connected to receive the electrical output of said sensing element means and producing a first output signal responsive thereto, said first network being quickly responsive to changes in said detected noise by virtue of said short time constant rendering said first output signal representative of sudden changes in said detected noise; a second network having a relatively long time constant connected to receive the electrical output of said sensing element means and producing a second output signal responsive thereto, said second network being slowly responsive to changes in said detected noise by virtue of said long time constant rendering said second output signal representative of a continuously readjusted ambient level of detected noise; comparator means connected to receive said first and second output signals of said first and second networks for producing a signal only when said first output signal is greater than said second output signal; and alarm means actuated by said signal for providing an alarm indication only when said first output signal is greater than said second output signal.
Claim 3
Dependent Claim
14 words
The circuit of claim 1 wherein said sensing element means comprise series connected coils.
Claim 4
Dependent Claim
31 words
The circuit of claim 1 wherein said sensing element means comprise coils, the output polarities of approximately half of said coils being opposed to the output polarities of the remaining coils.
Claim 5
Dependent Claim
79 words
The circuit of claim 1 wherein said alarm means comprises a relay having a coil connected to receive the output of said comparator means; and an alarm circuit including an alarm device, a capacitor, a power source and the contacts of said relay; one of said contacts being normally closed and connecting said power source to said capacitor and another of said contacts being normally open and connecting said capacitor to said alarm device when said relay is energized.
Claim 6
Dependent Claim
43 words
The circuit of claim 1 wherein said sensing element means comprise series connected coils, one half being of reversed polarity relative to the other half, said coils being positioned below ground level to detect electromagnetic noise from the electrical systems of automotive vehicles.
Claim 7
Independent Claim
91 words
The method of indicating the arrival in a surveillance region of a noise-producing object which comprises: detecting the noise level in such surveillance region and producing a first electrical signal responsive thereto; detecting an increase in noise level in a portion of such surveillance region and producing a second electrical signal in response to such increase; comparing said first and second electrical signals and producing an indication only when said second signal exceeds said first signal; and continuously reestablishing said first signal in response to changes in such preexisting noise level.
Claim 8
Independent Claim
91 words
The method of indicating the arrival in a surveillance region of a noise-producing object which comprises: detecting the noise level in such surveillance region and producing a first electrical signal responsive thereto; detecting an increase in noise level in a portion of such surveillance region and producing a second electrical signal in response to such increase; comparing said first and second electrical signals and producing an indication only when said second signal exceeds said first signal; and continuously reestablishing said first signal in response to changes in such preexisting noise level.
Claim 9
Dependent Claim
33 words
The method of claim 6 wherein the preexisting noise level is detected at a number of locations throughout such surveillance region and noise common to a plurality of such locations is substantially cancelled.
Claim 10
Dependent Claim
19 words
The method of claim 7 wherein the noise detected is electromagnetic and such detection is accomplished by electrical coils.
Claim 11
Dependent Claim
33 words
The method of claim 8 wherein cancellation is achieved by connecting said coils in series with the polarities of approximately half of the coils being opposed to the polarities of the remaining coils.
Claim 12
Dependent Claim
43 words
The method of claim 6 wherein said first electrical signal is the output of a first electrical circuit having a relatively long time constant and said second electrical signal is the output of a second electrical circuit having a relatively short time constant.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |