Design of high performance tunnel diode oscillator transducers

Tunnel diode oscillators (TDOs) are capable of far greater accuracy and precision than is suggested by their past usage. In a previous paper, the formula governing the ultimate sensitivity of TDO transducers was discussed. The specific considerations involved in building TDOs which approach this ultimate sensitivity is presented here. The design of a highly sensitive apparatus for measurement of the temperature dependence of surface impedance and magnetic susceptibility at frequencies below 10 MHz is described first. Then the optimum geometry for experiments which use the capacitor as the transducing element or which need a well-defined inductor at frequencies from 20 to 100 MHz is briefly mentioned. Finally, a discussion of the effect of diode nonlinearities on the circuit performance is presented. (Auth.)