Method and device for quantization of the response signal differences during synchronous measurement

摘要

The invention is intended for synchronous (lock-in) measurement devices, where not only the long term average, but also changing part of the response signal is of interest. Invention is especially suitable when said changing part is small compared to said long term average. Typical device would be impedance measurement device, where current is passed through object or substance with measurable impedance and response voltage on the object is acquired and processed. Adjacent in time samples are acquired synchronously to the excitation signal, and preprocessed. Difference of said samples is then quantized. Described invention is particularly useful in measuring bioimpedance.