How high-precision digital multimeter works
Digital multimeters are high precision instruments. The digital multimeter's dual-integration ADC is a key component for high-performance expression.
The dual-integrated ADC consists of two parts: the first part is the charging and integrating circuit; the second part is the discharging part.
In the rising portion, the unknown signal charges the integrator for a fixed time (t1) (the integration time is usually an integer multiple of the mains cycle to suppress mains interference). In the falling portion, the integrator discharges at a fixed rate according to the reference voltage, and t2 is the discharge time, which is counted by the counter to measure the unknown input voltage.