An automatic device is described which allows the continuous measurement of the resonant frequency and /b Q/ factor of a microwave cavity to accuracies within 100 parts in 10/sup 6/ and a few per cent., respectively.
Eugene, G., & Mollet, B. (1972). Automatic measurement of microwave-cavity parameters using stable sampled control loops. Electronics Letters, 8(17), 434-436. https://hdl.handle.net/2078.5/149346 (Original work published 1972)