A signal repeater amplifier system

摘要

1,081,290. Frequency-changers; radio signalling. NATIONAL AERONAUTICS & SPACE ADMINISTRATION. Dec. 7, 1964 [Dec. 17, 1963], No. 49773/64. Headings H3F and H4L. A signal repeater system for a space satellite includes an amplifier/frequency changer which changes the input frequency F 0 to F 1 ( = F 0 Π#F), a frequency-selective circuit which returns F 1 to the input of the amplifier where it is changed to F 2 (= F 1 Π#F), and a second frequency-selective circuit which passes F 2 as the desired output frequency. In the preferred method the amplifier/frequency changer is a travelling-wave tube operating in the serrodyne mode, i.e. having a sawtooth waveform of repetition rate #F applied to the helix, and F 0 F 1 and F 2 are microwave signals.