The Hewlett Packard model 3575A Gain-Phase Meter is a versatile, wide range ac voltage analyzer which affords direct convenient measurement of amplitude and phase parameters. The major feature of the instrument include broadband frequency response, wide dynamic range, digital readout plus a unique detection scheme which ensures accurate phase measurement in the presence of noise and distortion. These standard features, along with a variety of options including dual panel meters, BCD output, and remote control, make the 3575A a truly flexible instrument that is well suited for bench or systems applications.