GB1013930A - Parametric amplifiers - Google Patents

Abstract

1,013,930. Parametric amplifiers. NIPPON ELECTRIC CO. Ltd. June 22, 1962 [June 24, 1961], No. 24168/62. Heading H3B. A parameter amplifier has wave filters for the input and pump waves S, P and optionally for the output wave S0, which filters have different input and output coupling coefficients and together with the transmission lines which connect them to the variable reactance element form resonant circuits at the input output and pump frequencies. Two embodiments of suitable filters are described. The one shown in Fig. 5 for use in a coaxial cable comprises a cavity into which the centre conductors S5, S6 extend for different distances and the other (Fig. 6, not shown) for use in a waveguide is formed by having different sized windows in two partitions across the waveguide. Fig. 11 shown an embodiment for use with coaxial lines having a line 118, 119, 113 for each of the input, output and pumping frequencies and a fourth line 114 terminated by a variable reactance diode 115. Fig. 13 shows an embodiment for use when the pumping frequency is almost twice the signal frequency, the cut-off frequency of the waveguide 152 being greater than the signal frequency.