Accession Number : ADD013294

Title :   Linear Frequency Sweep Generator for Continuous Transmission FM Sonar.

Descriptive Note : Patent, Filed 2 Oct 81, patented 9 Aug 83,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Zehner, William J

Report Date : 09 Aug 1983

Pagination or Media Count : 4

Abstract : A device for producing a varying frequency sine wave synthesized so that the frequency is swept linearly with time for use in a continuous transmission FM sonar. A crystal clock, divider and a 16-bit digital output sweep pointer produce 2 to the 16th power counts for each sweep period Ts. The 2 to the 16th power counts are applied to a 16 bit digital analog converter to provide a highly linear voltage ramp (the smoothed result of 2 to the 16th power steps). The ramp is converted to a proportional frequency which is applied to a 5 bit digital counter to access a read only memory programmed to provide a digital to analog converter to produce a voltage output that is a 32 stepped approximation of a sinewave at a frequency which increases between f1 and f2 with linearity of the ramp voltage. A filter smoothes the output.

Descriptors :   *PATENTS, *SONAR EQUIPMENT, *SIGNAL GENERATORS, FREQUENCY MODULATION, ECHO RANGING, SWEEP FREQUENCY TECHNIQUES, TARGET RECOGNITION, TARGET ECHOES, TARGET DESIGNATORS, SIGNAL PROCESSING, SOUND TRANSMISSION, SOUND RANGING, SWEEP GENERATORS, INVENTIONS

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE