reciprocal frequency counter

[Martin Czech]

Sometimes it would be nice to have a DVM and a frequency counter
as a module for a modular system. E.g for tuning and trimming procedures
as well as for practical work.

DVM is no problem, there are 5 digit kits available. 

Most frequency counters suffer from the fact that they need very
long gate times for audio frequencys, ie. much latency. Of course,
one could measure the period instead, but say in 2 seconds how many
Hertz are 1/0.003674 s ?  (A very "clever" person suggested using a pll,
to make the frequency higher ...) Therefore reciporcal counters exist,
with a microcomputer inside that does this operation for the user, so
you really measure period, but get a frequency reading. Up to now, you
could buy these things for $500 or so at RS etc., now I've found a kit to
do your own for a modest price at ELV Electronics, (http://www.elv.de),
a german company that does kits and complete devices. I found it in their
free catalogue, not on the web.

m.c.