GB1017095A - Electrical reactance amplifiers - Google Patents

Abstract

1,017,095. Parametric amplifiers. TEXAS INSTRUMENTS Inc. Dec. 31, 1962 [May 22, 1962], No. 49036/62. Heading H3B. A forwardly biased PN junction device is used as a resistive load in the idler circuit of a reactance amplifier. Resistance is employed to restrict the output to the amplifying range. A PN junction device gives less noise than a normal resistor. As shown in Fig. 1, the non- linear element of a reactance amplifier is a reverse biased varactor 59. Tank circuits with reactive elements 50 and 51, 52 and 53, 57 and 58 are tuned respectively to the signal, idle and pumping frequencies. Across the tank circuit timed to the idler frequency is connected a PN junction diode 54 forwardly biased by a current source 56. The amplified signal is fed to a receiver load 64. In Fig. 2 (not shown), a bridge circuit including reverse biased variable capacitor diodes 104, 106 is pumped from a source 100 so as to constitute a varying capacity across the tank circuit 110 and a capacitor 113. The tank circuit is timed to the pump frequency. The input signal is applied across the capacitor 113. The output signal is coupled to the forward biased base emitter PN junction of transistor 120.