Patent ID: 7830294

Claim:
A measurement amplification device for detecting the detuning of a measuring bridge to which a bipolar, rectangular supply voltage (U S ) is supplied, comprising: an integrating A/D converter which generates a digital output value representing the bridge detuning, based on an analog, bipolar detuning signal (U V ) of the measuring bridge, wherein the A/D converter comprises: an integrator which integrates (a) either the detuning signal (U V ) or a bipolar signal derived from the detuning signal, as a measured signal which is continuously applied to said integrator during operation, and (b) a working level of a reference signal (U ref ) which is applied to said integrator intermittently, a comparator connected downstream of the integrator, said comparator comparing an integrator output signal with a threshold value, a time measurer determining a duration of each measured interval (T m ) during which the working level of the reference signal (U ref ) in addition to the measured signal is applied to the integrator, as a basis of a measure for the bridge detuning, wherein the comparator determines each time point at which the integrator output signal crosses the threshold value and, in accordance with the crossing time points detected, a controller controls: a switchable supply voltage source to undertake a polarity change of the supply voltage (U S ), and a switchable reference voltage source to disconnect the working level of the reference signal (U ref ) from the integrator, so that the reference signal and the supply voltage are mutually synchronized in bipolar manner.