Project Echo: Standby Receiver System

The Echo T 2390 mc receiving system* is shown in block diagram form in Fig. 1. The masers and parametric amplifiers are shown in parallel in the over-all system. Since the parametric amplifier system must provide performance similar to that portion of the primary system it parallels, it must have comparable gain and bandwidth, and must have an acceptable noise figure. In addition to the general requirement that the parametric amplifier system be independent of the maser system, there were a number of specific requirements. The input frequency was 2390 mc and the output frequency was 70 mc. For system compatibility the parametric amplifier system, including the down-converter and IF amplifier, had to provide at least 00 db over-all gain. The minimum band width for the planned experiments was 5 mc. Considerations of the transmitter power and antenna gain at the Jet Propulsion Laboratory facility at Goldstone, California, the path loss, and the Holmdel antenna gain and noise temperature indicated that a noise temperature of 300°K would be acceptable for the standby system. * Although this equipment was designed by the Bell System as part of its research and development program, it was operated in connection with Project Echo under Contract NASW-110 for t he National Aeronautics and Space Administration. 1129