RadioBanter - View Single Post

October 13th 03, 04:36 AM

In article ,
writes:

I'm going to eventually use some moderately-high input Z comparators
after extreme narrowband filtering, that to square it up for CMOS TTL
digital levels. That isn't a necessary, just a convenience for me. If
the amplified signal level can get above about a half Volt p-p, then
an ordinary digital Schmitt trigger gate or inverter will act just fine to
square up the signal, make it compatible with other digital packages.
Did that before for other applications and no problem.

Squaring-up the received signal doesn't offer much for improving the
signal to noise ratio. That may make it LOOK like it is "noise free"
but that is only because the existing noise is transferred from the
vertical direction of a scope picture to the horizontal. It's harder to
observe the horizontal display noise due to the very fast transition
of a comparator or trigger output. Squaring up is absolutely necessary
to couple the signal to any kind of digital circuit for time decoding.

Your ok so long as the ampliflier and squarer upper dooper doesn't leakyage
back into the loopy thing or previous ampliflying bits.

Thank you for the advice on the "squarer upper dooper" and the
"leakage back into the loopy thing" and the "amplifying bits."

Len Anderson
retired (from regular hours) electronic engineer person