Qiong Xiang

A Complex Voltage Ratio Measurement System for the Audio Frequency Range

This paper describes the setup of a complex voltage ratio measurement system for the audio frequency range. A wideband two-channel digitizer and a differential analogue channel switching front-end are used as the heart of the system. The complex error, frequency response characteristics and short term stability of the system are tested in this paper. The errors range from 1×10-7 at 50 Hz to 10×10-6 at 200 kHz in ratio 1:1 test with 6 V input voltages. And errors are below ±8×10-7 and ±0.06 μrad in ratio 1:1 test with a 4V power line (50 Hz) input voltage over 64 hours. The test results and comparisons between with and without channel exchange mode confirm the remarkable improvement regarding the suppression of the static mismatch errors of the digitizer and show the usefulness of the system at 50 Hz too.