Multiple slope analogue=to=digital converter with integrating amplifiers - increases resolution to two and a half bits with reduced influence of reference current switch faults

摘要

Two cascaded amplifiers (15,16) continuously integrate the input current (Ie) as well as two pulsed reference currents (I1,I3) controlled by a comparator (26), a logic circuit (20) including a random number generator (21), a pulse counter (19) and two bistables (22,27). A reversible counter (28), logic (29) and a frequency divider (30) guarantee a fixed ratio of reference current switching periods. One current (I3) is measured by counting (24) pulses passing through a gate (23) from a pulse generator (18). USE/ADVANTAGE - Esp. in precision measurement of voltages and currents. Noise at frequencies well below measuring ramp frequency is reduced by more than 30 dB.