Active Solid-State Devices

Twenty new solid-state devices were developed to meet the TD-3 requirements. The FM terminal transmitter needed a variable capacitor diode (457A) as the active element in the deviator, a very stable voltage regulator diode (446AC), and a transistor oscillator (44A). A family of medium-power varactors (473A, B, and C) was required for the microwave carrier supply. A high-quality silicon varactor diode pair (471A) was developed for the transmitter modulator. Two new 1323 1324 TI-IE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1968 rectifiers (463A and 464A) were developed for the high voltage power supply for the traveling wave tube. For the receiver, a low-noise gallium arsenide Schottky-barrier mixer diode (497A) and a low-noise IF preamplifier transistor (45.1) were developed to assure the low-noise figure required of the TD-3 repeater. The second stage of the preamplifier required a transistor that could handle a large signal without harmful distortion (45G). The FM receiver also needed a transistor with controlled input impedance (45B) and a silicon Schottky-barrier diode (479A) in the IF amplifier-limiter, and a similar diode (479B) in the discriminator. The 45C transistor was developed for locations where the signal level exceeds the level at which the 45B transistor can maintain sufficiently low distortion. A silicon p-i-n diode (474A) was developed for the variolosser. Two silicon point contact diodes (488A and 493A) were developed for use in IF and RF monitor circuits. I.