A modern precision automatic SINAD meter, distortion meter and true RMS voltmeter

In all receiver engineering with similar types of modulation the data for the redeiver performance refer to signal-to-noise ratio and noise figure either directly or indirectly. The quality of the audio signal is evaluated by the distortion factor or signal breakdown. To simplify the measurement procedures a SINAD meter is used. The equipment presented in this paper combines a distortion factor meter with a true RMS voltmeter with 102 dB range and a automatic SINAD meter, in fact all the capabilities of a laboratory instrument (for the AF side) to make measurements precisely and efficiently. A CCITT weighting filter permits, if required, correct evaluation according to the standard.