1
Douglas J Rogers: Position encoder. Ferranti, Kerkam Stowell Kondracki & Clarke, June 18, 1985: US04524347 (26 worldwide citation)

A position measuring device includes a conventional encoder, a scale member and an index member together arranged to provide two periodic waveforms of the same frequency and in quadrature with one another. Errors in the waveforms are corrected, and the corrected waveforms used to produce an indicati ...


2
Brian E Pitches, Robert M S Murray, Douglas J Rogers: Capacitance measuring apparatus. 501 Ferranti, Kerkam Stowell Kondracki & Clarke, July 12, 1983: US04392378 (13 worldwide citation)

Capacitance measuring apparatus comprises a variable capacitor VC and a reference capacitor FC. Circuits D, ID, are provided for generating a periodic waveform for application directly to the variable capacitor, and in inverted form to the reference capacitor. Switches means SM are operated by contr ...