January 1980 v.31 n.1 Cover: Model 4191A RF Impedance Analyzer Automated Testing of PCM Communications Equipment with a Single Self-Contained Instrument. Microprocessor control of multiple sources and detectors within this compact instrument achieves a new level of automation for voice-channel measurements in PCM multiplex equipment, by Mark Dykes, Andrew Batham, Virgil Marton, Robert Pearson, Mike … Continue reading 1980 – HP Journal Index