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Title: Range-gated field disturbance sensor with range-sensitivity compensation

A field disturbance sensor operates with relatively low power, provides an adjustable operating range, is not hypersensitive at close range, allows co-location of multiple sensors, and is inexpensive to manufacture. The sensor includes a transmitter that transmits a sequence of transmitted bursts of electromagnetic energy. The transmitter frequency is modulated at an intermediate frequency. The sequence of bursts has a burst repetition rate, and each burst has a burst width and comprises a number of cycles at a transmitter frequency. The sensor includes a receiver which receives electromagnetic energy at the transmitter frequency, and includes a mixer which mixes a transmitted burst with reflections of the same transmitted burst to produce an intermediate frequency signal. Circuitry, responsive to the intermediate frequency signal indicates disturbances in the sensor field. Because the mixer mixes the transmitted burst with reflections of the transmitted burst, the burst width defines the sensor range. The burst repetition rate is randomly or pseudorandomly modulated so that bursts in the sequence of bursts have a phase which varies. 8 figs.
Inventors:
Issue Date:
OSTI Identifier:
238064
Assignee:
Univ. of California, Oakland, CA (United States) PTO; SCA: 440800; PA: EDB-96:095354; SN: 96001594371
Patent Number(s):
US 5,521,600/A/
Application Number:
PAN: 8-300,769
Contract Number:
W-7405-ENG-48
Resource Relation:
Other Information: PBD: 28 May 1996
Research Org:
University of California
Country of Publication:
United States
Language:
English
Subject:
44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; MEASURING INSTRUMENTS; DESIGN; ELECTROMAGNETIC FIELDS; DISTURBANCES; OPERATION; COST; ELECTROMAGNETIC RADIATION; FREQUENCY MODULATION; SENSITIVITY; MONITORS; COORDINATES