A Thermistor Bridge Correlator
Victor C. Anderson, Philip Rudnick · Review of Scientific Instruments · 1953
A circuit is described for the measurement of a correlation coefficient between two continuous signals. The method depends on an accurate mean square element which is obtained through the i2r heating of a thermistor. Relatively simple circuit features give accuracy to about 1 percent, even though the resistance of the thermistor varies by about 25 percent between zero and full input.