Good thinking Bob, I will look in to it. Do you have a schematic or the model number of the squelch you were working with?
A couple of friends in Erie were recently pulling their hair out with a COR-2 by VHF engineering. That needed a serious redesign, not having a pull-up resistor on the RX board was and the of the COR input transistor not having a resistor in the base come to mind. I would think ringing would be a problem with passive components Like L/C filters. But it may exist in a low quality op-amp that is not designed with a wide bandwidth. I believe the LM324 series is only rated for 12kHz of bandwidth, the TL084 is about 3MHz. I am not even sure if I can simulate impulse noise. But in theory we can write a software algorithim to look for a patterned pulse and attempt to compenstate. I should mention I have a preliminary schematic in the files section as well should anyone care to offer suggestions or modifications. > Be careful with sharp skirts on your noise filter. I've seen very high Q > noise filters in squelch circuits cause some strange effects due to > ringing. The old Hamtronics squelch would tend to act tight in the > presence of impulse noise such as precipitation static or radar. > > Check the transient response before finalizing your design. > > Bob NO6B
