In this neck of the woods "active" usually means the meter has
peak reading circuitry that requires power to operate. In general,
as far as ordinary peak reading meters, this is the most accurate
type as far as trying to read voice peaks. The better ones use
fast acting LED's as the meter.

If by "active" one just means that the meter requires power, then I would see
little difference between an active and a passive circuit as far as
intermodulation is concerned.

As a matter of fact if, in an "active" meter, the amplifier (or the active
display) follows the diodes, there would be no difference at all (as to
intermodulation) with respect to a passive meter.

If the amplifier is instead put before the diodes, the intermodulation products
generated by the diodes (if any) can get coupled to the line.

In summary the distinction is between a circuit in which the diodes are directly
coupled to the line and a circuit in which there is an isolating stage between
the line and the diodes. And not between a passive and an active circuit.

73

Tony I0JX