A method of amplitude and phase measurement in the v.h.f.- u.h.f. band

A null method has been devised for measuring changes in the amplitude and phase of the transmission characteristic of a network at any frequency in the range 41¿1000 Mc/s. A commercial instrument, designed for admittance measurement, is used with only slight modification for this application. Its subsequent use as an admittance meter is unaffected. The measurement of phase can be made to within about ±3°, unless a large variation of amplitude is encountered, when reading accuracy limits the accuracy of phase measurement in the regions of small amplitude. If the error in a measurement is regarded as a vector, then, with any amplitude variation, the maximum value of the magnitude of this error vector is about 6% of the full-scale reading of the instrument.