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FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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The paper discusses the fundamental theory and construction of parametric amplifiers. The power source of a parametric amplifier comes from a high-frequency oscillator. Variable parametric amplifiers with variable-capacitance p-n junction diodes have a lower noise figure than electron tube amplifiers. Capacitance of a p-n junction diode can be changed by varying the external voltage supply to the unit. The requirements of variable-capacitance parametric amplifiers are low quiescent capacitance, wide capacitance variation range, and high quality factor. Parametric amplifiers derive their pump power from an a.c. power supply unit. Theoretical studies and experiments verified that the frequency of a pump signal is several times higher than the frequency of an incoming signal, e.g., an incoming signal of 1000 mc may require a pump frequency of 10,000 mc or higher. The sum and difference are obtained by mixing the incoming signal frequency and pump frequency in a converting circuit. The converting circuit operates on the same principle as a superheterodyne receiver. Author points out that variable-inductance elements and special electron-beam tubes can also be used in parametric amplifier construction. Author
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