Theory of Operation and Circuit Description, Programmable 20-Bit Pseudorandom PRF Generator, Revision 1,

The programmable 20-bit pseudorandom pulse-repetition-frequency PRF generator was designed and constructed by the Naval Weapons Center for eventual use with a phased-array antenna radar. However, the unit has general utility and can be used as the PRF generator for any radar set which requires trigger pulses having a peak voltage of 2 vdc, pulse width of 0.33 microsec, repetition rate ranging from 280 to 2,000 pps, and a jitter percent of 0, 12.8, 25.6, or 38.4. When operated in the jitter mode each series of 2 to the 8th power pulses has a particular spacing pattern. The spacing pattern is different for each of 2 to the 8th power pulses until the 2 to the 12th power series is reached. After the 2 to the 12th power series 2 to the 20th power pulse the spacing pattern is repeated, hence the designation pseudorandom. One unique feature of the circuit is that, irrespective of the jitter percent used, the average pulse rate remains constant, thus providing uniform average power loading on the final stages of the radar transmitter. Digital logic modules using integrated circuits are utilized throughout the equipment, except in the self-contained 6-Mc clock-pulse oscillator. An external clock-pulse generator can be used if desired. Author