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
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01S - RADIO DIRECTION-FINDING
- 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}
}