GB933446A - Diode parametric amplifier - Google Patents

Abstract

933,446. Parametric amplifiers. MULLARD Ltd. June 3, 1960, No. 19761/60. Class 40 (9). A parametric amplifier comprises a length of coaxial line A and three independently-adjustable tuning devices K, F, E for tuning the coaxial line to resonance at signal, pump and idler frequencies and a voltage dependent reactor C such as a crystal diode connected between the inner and outer conductors. Figs. 3, 4 and 5 show the voltage distribution for the signal, pump and idler frequencies. Tuning to the idler frequency is first effected by moving a short-circuiting plunger E. The pump frequency is injected by a probe G at a position corresponding to a voltage node at which position the capacitative probe for tuning to the pump frequency is located. The pump frequency tuner F is also located as near to a voltage node of the signal frequency as possible. Thus adjustment of this tuner effects the tuning of the other frequencies only very slightly. The signal input probe H, the signal output probe J and the capacitative probe K which effects the tuning at the signal frequency are located near the voltage nodes of the pump frequency and the idler frequency for minimum interference with the tuning for these frequencies. The coaxial line may be of any odd number of quarter wavelengths of the signal frequency and use plunger tuning as shown, or may be of an even number of half wavelengths, the left-hand end being then open-ended and tuned by a variable capacitor.