Frequency Agile Amplifier.
Final technical rept. 30 Jun 67-28 Feb 69,
RADIO CORP OF AMERICA MOORESTOWN NJ DEFENSE ELECTRONIC PRODUCTS
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A development amplifier was built to verify the practicability of high speed electronic tuning by applying a control current to set the inductance of ferrite cores in both grid and plate circuit resonators in an HF amplifier. This development applied design methods and criteria established in a previous feasibility study. A 600 KW amplifier was designed, constructed, and evaluated, with results fulfilling the promise of the feasibility study. Performance attained includes linear operation at more than 50 percent plate efficiency over a tuning range of 4.7 to 30.5 MHZ more than 2.5 octaves. A single control current tunes both plate and grid tank circuits, and a unique circuit used in conjunction with the plate resonator allows the amplifier output to match a 50-ohm load with less than 20 impedance variation across the frequency band. The ferrite-loaded grid tuner, in conjunction with a broadband ferrite core transformer, permits input VSWR less than 1.2 across the band. Although transistorized high speed tuning circuits were not developed, tests were conducted to support the feasibility of achieving tuning speeds of less than 100 milliseconds, and probably less than 30 milliseconds. Substantially improved ferrites for this work were developed during the program, supporting the judgement that continued enhancement of this technique can result from continued development effort. Author
- Electrical and Electronic Equipment