The errors of differential balanced measuring circuits

Conclusions

We have estimated the mean-square errors of two forms of balanced differential measuring circuits differing in respect of the positioning of the executive organ.

We have determined the optimum values of the parameters of the balanced circuits minimizing the measuring error. We have shown that for incomplete correlation between the random variations of the signals being compared the optimum setting of the circuit differs from that usually employed. We have made a comparison between the minimum errors of unbalanced and balanced measuring circuits and have calculated the gain in accuracy obtained on replacing an unbalanced measuring technique by a balanced one. We have found that, for low modulation indices of the probing signal representing the quantity being measured, the use of a compensated measuring circuit instead of an unbalanced one does not increase the measuring accuracy and is therefore undesirable.