GB1036333A - Parametric amplifier - Google Patents

Abstract

1,036,333. Parametric amplifiers. STANDARD TELEPHONES & CABLES Ltd. April 19, 1963 [April 25, 1962], No. 15479/63. Heading H3B. A parametric amplifier tunable over a range of frequencies comprises a coaxial line section 1 the inner conductor 7 of which is in sliding engagement with a short-circuiting block 9 and determines the position of a shorting block 12, the pump circuit 27 being capacitively coupled to the coaxial line section, and the signal and output circuits 22, 35 being inductively coupled both to the coaxial line section and to each other. Consequently an input signal appears in the output even if the pump signal ceases. The end of the inner conductor 7 within the outer coaxial conductor 8 is physically and electrically connected to the shorting block 12 by a varactor diode 5 and an annular condenser 16, the diode having plugs 18, 19 which engage sockets 17, 20 on the condenser and inner conductor respectively. A D.C. bias source 36 or current monitor 38 may be selectively connected by a switch 37 to the diode by a circuit which passes through the annular condenser. Coaxial conductors 4, 6, 28 are used for the pump, signal and output circuits, the inductive couplings being formed by the extended inner conductors 24, 32 which are secured by solder to the outer face of short-circuiting block 9. Both inductive couplings are coupled to the coaxial line section at the same low impedance point, while the capacitive pump coupling 30 is positioned at a high impedance point. Frequency examples given are signal frequency in the range 950 to 1230 mc/s. and pumping frequency about 400 mc/s. higher.