Accession Number : AD0820216

Title :   INTERFERENCE REDUCTION TECHNIQUES FOR PULSED TRANSMITTERS.

Descriptive Note : Rept. no. 4 (Final), 15 Jul 65-31 Apr 67,

Corporate Author : ENERGY SYSTEMS INC PALO ALTO CA

Personal Author(s) : Goldfarb, Eli M. ; Cumming, Raymond C.

Report Date : JUL 1967

Pagination or Media Count : 124

Abstract : The purpose of this project is to investigate the interference producing characteristics of pulsed transmitters and then to seek methods to minimize this generation of spurious emission exclusive of filtering and shielding. The effect of various pulse shapes on the radar transmitter performance including EMC was studied. Particular attention was given to a class of flat-top pulses with confined spectra that are suitable for high efficiency transmitter operations. Tables and graphs are included to facilitate making a choice of pulse shape. A nearly gaussian periodic pulse train was analyzed. Its spectrum is bounded and the time-domain signal consists of periodically repeating pulses whose interpulse amplitude is approximately zero. Practical methods of video waveshape generation were investigated using active shaping circuitry. Amplifier and diode modulator nonlinearity and their effects on spectrum degradation were investigated. The frequency modulation and envelope distortion caused by the nonlinear characteristics of the microwave tube whether operated as an amplifier or a modulated amplifier were investigated. Amplitude modulation-phase modulation conversion curves for typical klystrons, traveling-wave tubes, Klystrons and cross-field amplifiers plotted as functions of input signal level were compiled. The gain saturation curves were used to relate the AM/PM conversion curves to output voltage level. The resulting curves were compared to several phase-envelope functions previously analyzed. Absorption modulators were reviewed briefly.

Descriptors :   *ELECTROMAGNETIC COMPATIBILITY), (*RADAR TRANSMITTERS, (*RADAR INTERFERENCE, REDUCTION), RADAR PULSES, RADIOFREQUENCY PULSES, FREQUENCY, AMPLIFIERS, PHASE MODULATION, AMPLITUDE MODULATION, POWER AMPLIFIERS, MODULATORS.

Subject Categories : Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE