- Abele T.
- Leonard D.
The microwave generator is a highly frequency-stable, low-noise source of microwave power which is the local oscillator supply for the T D - 3 microwave transmitters and receivers. It delivers 0.5W output power and is adjustable to any one of 17 different frequencies: 3780, 3800 . . . 4100 MHz.* To achieve great reliability, minimum maintenance, and low power consumption, it was decided to use only solid state devices. Various devices were considered: varactors, step recovery diodes, and transistors; however, at design time, varactors were the only solid state devices that appeared able to operate at the required frequencies and provide the power levels and reliability demanded. Once varactors were chosen it was possible to determine the over-all circuit configuration. A crystal oscillator operating in the range of 125 MHzf was needed to obtain the required frequency stability. Then a chain, consisting of a cascade of several varactor multipliers, was used to obtain efficient frequency multiplication up to 4000 MHz. A power amplifier had to be inserted between the oscillator and the * This equipment is manufactured for Bell System use only. t In general 125, 500, 1000, and 4000 MHz are used to denote any frequency between 118.125 and 128.125 MHz and their fourth, eighth, or thirty-second multiple, respectively. 1301