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Title: GROUND CLEARANCE INDICATOR

Abstract

A narrow-band frequency-modulated distance measuring system is described. Reflected wave energy is fed into a mixer circuit together with a direct wave energy portion from the transmitter. These two input signals are out of phase by an amount proportional to the distance. Two band pass filter s select two different frequency components (both multiples of transmitter modulation frequency) from the beat frequency. These component frequencies are rectified and their voltage values, which are representative of those frequencies, are compared. It has been found that these voltages will have equal values producing a null output only when an object attains a preselected distance. The null output may be utilized to operate a normally closed relay, for example. At other ranges the voltage comparison will yield a voltage sufficient to keep the relay energized. Ranges may be changed by varying the degree of modulation of the transmitter carrier frequency. A particular advantage of this system lies in its high degree of accuracy throughout a range of distances approaching zero as a minimum.

Inventors:
Issue Date:
Research Org.:
Originating Research Org. not identified
OSTI Identifier:
4208554
Patent Number(s):
2907023
Assignee:
U.S. Atomic Energy Commission DTIE; NSA-14-006497
NSA Number:
NSA-14-006497
Resource Type:
Patent
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-60
Country of Publication:
United States
Language:
English
Subject:
ENGINEERING AND EQUIPMENT; CIRCUITS; ELECTRONIC EQUIPMENT; ENERGY; FREQUENCY; MEASURED VALUES; MODULATION; OPERATION; RADIO WAVES; RECTIFIERS; REFLECTION; RELAYS; SIGNALS

Citation Formats

Skinner, L.V. GROUND CLEARANCE INDICATOR. United States: N. p., 1959. Web.
Skinner, L.V. GROUND CLEARANCE INDICATOR. United States.
Skinner, L.V. Tue . "GROUND CLEARANCE INDICATOR". United States.
@article{osti_4208554,
title = {GROUND CLEARANCE INDICATOR},
author = {Skinner, L.V.},
abstractNote = {A narrow-band frequency-modulated distance measuring system is described. Reflected wave energy is fed into a mixer circuit together with a direct wave energy portion from the transmitter. These two input signals are out of phase by an amount proportional to the distance. Two band pass filter s select two different frequency components (both multiples of transmitter modulation frequency) from the beat frequency. These component frequencies are rectified and their voltage values, which are representative of those frequencies, are compared. It has been found that these voltages will have equal values producing a null output only when an object attains a preselected distance. The null output may be utilized to operate a normally closed relay, for example. At other ranges the voltage comparison will yield a voltage sufficient to keep the relay energized. Ranges may be changed by varying the degree of modulation of the transmitter carrier frequency. A particular advantage of this system lies in its high degree of accuracy throughout a range of distances approaching zero as a minimum.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1959},
month = {9}
}