Digital transfer voltmeters: principles and error characteristics

Precision measurements of the r.m.s. value of a fluctuating voltage may be made using sampling and digital techniques. Although considerably more complex than analogue methods, the sampling voltmeter has substantial advantages in many respects. The paper discusses the principles on which the meter is based. Its error characteristics are derived and analysed for four periodic waveforms and for white noise. Using the results of the error analysis, design criteria are discussed. Finally, the principal requirements for a special-purpose digital computer to produce the meter reading are established.