A panoramic receiver (3.5¿20 Mc/s)

The receiver is designed to indicate the presence, frequency and relative magnitude of strong signals in the frequency band 3.5¿20 Mc/s, displaying all such signals simultaneously in ¿panoramic¿ form on a 12-in cathode-ray tube. To cover this large frequency range in the one instrument, a superheterodyne arrangement with the intermediate frequency higher than the signal frequencies is employed. The beating oscillator frequency is varied cyclically in sawtooth fashion by means of a motor-driven rotating capacitor. The output of the final detector is applied to the Y-deflection of the tube, and the X-deflection is derived from a sawtooth generator. The latter is synchronized with the frequency sweep by means of pulses, developed at a predetermined point in the cycle by applying the beating oscillator output to a tuned amplifier.