The nominal level and the reference voltage against which it is expressed depend on the line level being used.
The advantage here is that the clamping level is at precisely the reference voltage.
A front end processor provides a reference voltage, measures the output of the network, and calculates the dew point.
This provides a common reference voltage for all electrical equipment.
The i.c. also contains a regulator to provide a reference voltage.
In most cases, for positive input voltages, this means that the reference voltage will be negative.
If the integrator's output were positive, a positive reference voltage would be required.
The output of the comparator is used by the converter's controller to decide which reference voltage should be applied.
Most comparator manufacturers also offer comparators in which a reference voltage is integrated on to the chip.
This gives the identity of the unknown voltage since the reference voltage is known.