US3972042A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal target detection system
Assignee: Motorola Solutions Inc
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Filing: 1974-12-02
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Granted: 1976-07-27
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Expires: 1994-12-02
Abstract
Abstract A system for differentiating between targets containing non-linear metal element junctions and their surrounding non-metallic environment. A spread spectrum illuminating transmitter is used in conjunction with correlation circuits in a receiver to enhance its signal to interference ratio and reduce required peak power level in the illuminator/transmitter.
Inventors
- 👤 Robert H. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:27
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/74; G01S13/75; G01S13/751; G01S13/753
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
50 words
A metal detection system comprising: means for radiating a spread spectrum signal to a metal target having a non-linear electrical response characteristic, said target radiating a harmonic signal in response to said spread spectrum signal; means for receiving the harmonic signal; and means for compressing and detecting the harmonic signal.
Claim 2
Dependent Claim
50 words
A metal detection system comprising: means for radiating a spread spectrum signal to a metal target having a non-linear electrical response characteristic, said target radiating a harmonic signal in response to said spread spectrum signal; means for receiving the harmonic signal; and means for compressing and detecting the harmonic signal.
Claim 3
Dependent Claim
102 words
The system according to claim 1, wherein said radiating means comprises: means for generating a pulse train with a predetermined repetition rate; means for generating a carrier signal, said carrier signal being modulated on and off by said pulse train and said carrier signal frequency being changed linearly during said on periods; means for lengthening the pulse duration of said frequency modulated carrier signal as a function of said carrier signal frequency; means for filtering said lengthened and modulated carrier signal for limiting said signal to a given spectrum width; and antenna means for radiating said filtered, lengthened, and modulated carrier signal.
Claim 4
Dependent Claim
15 words
The system according to claim 2, wherein said compressing means includes spread spectrum compressing means.
Claim 5
Dependent Claim
34 words
The system according to claim 1, wherein said receiving means comprises: antenna means for receiving said radiated harmonic signal from said metal target; and means for filtering out transmitted signal from the receiving means.
Claim 6
Dependent Claim
22 words
The system according to claim 1, wherein said means for radiating spread spectrum signal includes means for expanding a frequency varying signal.
Claim 7
Independent Claim
66 words
A system for guiding a mobile vehicle to a metallic target having a non-linear electrical response characteristic, comprising: transmitting means for generating and directing a spread spectrum signal to said target, said target radiating a harmonic signal having a harmonic component in response to said spread spectrum signal, and said vehicle having receiving means for receiving and compressing said target harmonic signal for detecting said target.
Claim 8
Independent Claim
66 words
A system for guiding a mobile vehicle to a metallic target having a non-linear electrical response characteristic, comprising: transmitting means for generating and directing a spread spectrum signal to said target, said target radiating a harmonic signal having a harmonic component in response to said spread spectrum signal, and said vehicle having receiving means for receiving and compressing said target harmonic signal for detecting said target.
Claim 9
Dependent Claim
48 words
The guidance system according to claim 6, wherein said transmitting means includes: means for generating a train of pulses, means for spreading the modulated pulse train, filtering out higher end frequency of the modulated pulse train, means for applying said filtered and modulated pulse train to said target.
Claim 10
Dependent Claim
49 words
The guidance system according to claim 6 wherein said receiving means includes: means for detecting a harmonic signal from said metallic target, means for filtering out unwanted transmitted signal and saving the harmonic signal, and said means for compressing the harmonic signal to increase sensitivity of said receiving means.
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) | 1979-07-27 | 1980-01-26 | 1980-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-27 | 1984-01-26 | 1984-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-27 | 1988-01-26 | 1988-07-27 | $7700.00 | Window Closed / Lapsed |