The design of signal generators for centimetre wavelengths

The function of a signal generator is to provide a test signal of known frequency and amplitude. In the design of such instruments for centimetre wavelengths, problems chiefly associated with the determination of the signal amplitude have necessitated some departure from conventional practice at lower frequencies. The main difficulties encountered have been in the design of a suitable output attenuator, together with a monitor by which the output may be maintained constant at some reference level, and the provision of adequate screening for the generator. This paper seeks to acquaint the reader with some of the methods that have been evolved to meet these problems, and includes a brief description of a typical signal generator operating in the 6-cm wavelength region. The paper is not intended to be a complete survey of the work which has been carried out on this subject during the war, but it is hoped that it will be of value in indicating some of the lines along which development has taken place.