An automatic Q-meter using the damped oscillation of a resonant circuit excited by a keyed signal
Y Komachi, Satoshi Tanaka · Journal of Physics E Scientific Instruments · 1974
In this Q-meter the resonant circuit under test is excited by a keyed signal at the resonant frequency and the induced damped oscillation is used to determine the Q factor. The initial amplitude of the damped oscillation can be built up to a desired value by increasing the excitation time. The excitation signal is provided by a tracking oscillator which generates signals at the resonant frequency.