GROUND CLEARANCE INDICATOR

Patent · Tue Sep 29 04:00:00 EDT 1959

OSTI ID:4208554

Skinner, L V

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.

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-14-006497
• Assignee: U.S. Atomic Energy Commission
• Patent Number(s): US 2907023
• OSTI ID: 4208554
• Country of Publication: United States
• Language: English

Related Subjects

CIRCUITS
ELECTRONIC EQUIPMENT
ENERGY
ENGINEERING AND EQUIPMENT
FREQUENCY
MEASURED VALUES
MODULATION
OPERATION
RADIO WAVES
RECTIFIERS
REFLECTION
RELAYS
SIGNALS