At 4/16/2007 15:22, you wrote: >Hello, > >This email message is a notification to let you know that >a file has been uploaded to the Files area of the Repeater-Builder >group. > > File : /FluX Research/Open Source D-Squelch > Uploaded by : dcflux <[EMAIL PROTECTED]> > Description : Discription of D-Squelch Project > >You can access this file at the URL: >http://groups.yahoo.com/group/Repeater-Builder/files/FluX%20Research/Open%20Source%20D-Squelch > >
within the above: >A 9 pole high pass filter is the star of the squelch system. >Exhibiting a near brick wall response it is a Sallen-Key Chebyshev >filter with 0.8dB of ripple in the pass band. This will exhibit 10dB >of gain with a Fc of 6kHz as well as exhibiting an eyepoping -68dB of >rejection at 3500 Hz and -55dB at 4000. 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
