Intra-spectral noise and transfer functions of pulsed final power amplifiers

The power spectrum and transfer functions have been examined for a variety of "X" band power amplifier tubes. The primary interest has been in the applicability of these tubes to second generation sophisticated electronic systems employing coherent doppler data processing. The amplifier tubes examined are the synchronized magnetron, the traveling wave tube, and a crossed field amplifier. The specific tubes employed in the investigation were the Litton 65 KW L6343A magnetron, the Hughes 50 KW traveling wave tube 307H, and the 500 KW SFD 218 crossed-field amplifier. Laboratory experiments were designed to provide primary data useful to the electronic system designer. This data consisted of the (1) intra-spectral noise characteristics of these pulsed amplifiers at low pulse repetition rates and (2) the gain and phase deviations as a function of frequency. The noise data was obtained for a 2 KC pulse rate and a selective filter bandwidth of 100 cps. Spectrum photographs indicating the intra-spectral noise level are provided for a dynamic range of 50 db. The transfer functions obtained for these tubes have been photographed for the frequency interval of interest and define the gain and phase deviations observed. A brief description and block diagram are provided of test equipment employed in performing the experiments.