Parametric action in transistors: Theory

Some observations on parametric action in transistor mixers

“…A first-order theory of parametric mixing at the collector-base diode has been presented, 10 together with some experimental evidence in support of this theory. 11 * 12 The experimental system which was investigated involved a common-base-connected 10 MHz amplifier incorporating a single u.h.f.…”

“…It is not difficult to show, 10 however, that direct parametric action at the emitter-base diode by means of the non-linear junction capacitance is insignificant in relation to resistive mixing, except at very small emitter currents and then the transistor gain at a> x is correspondingly low. The emitter-base diode has a low (^-factor f°r normal emitter currents, because the diffusion conductance greatly exceeds the shunt capacitive susceptance: on the other hand the collector-base diode has a relatively large g-factor since the collector capacitance is virtually unshunted and significant pumping of the collector junction capacitance can be achieved over a wide frequency range, with corresponding parametric mixing.…”