A simple and effective method for improving the accuracy of selective audio-frequency voltage measurements
Obradovic Mirko, Rodic Ranko, Arandjelovic Vojislav · Review of Scientific Instruments · 1994
An examination of the results of the accuracy measurements of a bench top audio-frequency selective voltmeter, based on the superheterodyne principle, showed that an accuracy of the order of only 10% of measured values could be achieved if no internal error correction procedure in the measurements had been used. The temperature variations of the parameters of the quartz band-pass filter have been identified as the main source of the measurement error. An application of the internal reference signal from a relatively simple and inexpensive source improved the overall accuracy up to the order of 3%. Finally, it was shown that by combining the wide band and selective measurements of the signals from the built-in tracking generator further improved the overall accuracy to better than 1% and eliminated altogether the need for using any separate source of internal reference signals.