A printed wiring board includes an input conditioner having a plurality of analog
dc inputs and a plurality of analog dc outputs; a switching circuit having an analog
dc output, the switching circuit being connected to the plurality of analog dc
outputs of the input conditioner; a sample and hold converter having an analog
dc output, the sample and hold converter being connected to the analog dc output
of the switching circuit; an A/D converter having a digital output, the A/D converter
being connected to the analog dc output of the sample and hold converter; a microprocessor
connected to the digital output of the A/D converter; a timer circuit connected
to the microprocessor; a random access memory connected to the microprocessor;
and a VME interface connected to the microprocessor. The printed wiring board further
comprises an ac multiplexer; a plurality of rms to dc converters connected to the
ac multiplexer, the rms to dc converters being connected to the switching circuit;
a zero crossing detector connected to the ac multiplexer; a phase detector connected
to the zero crossing detector and to the microprocessor; a filter connected to
one of the outputs of the zero crossing detector; and a frequency measurement circuit
connected to the filter and to the microprocessor.
