[Yaesu] FW: roofing filters

Adam Farson farson at shaw.ca
Fri Jul 21 13:30:33 EDT 2006


Hi Cecil,

All the IC-756Pro-series radios have 2 roofing filters - the first at 64.455
MHz, and the second at 455 kHz (actually a two-section filter with the NB
noise gate between the sections.) In the Pro and Pro2, the 64.455 MHz filter
is discrete; in the Pro3, it is the same MCF as used in the 7800.

http://www.nsarc.ca/hf/756p3_p2.pdf

By definition, a roofing filter is required in a superhet. The purpose of
the roofing filter is twofold: to suppress images generated by the mixer,
and to reduce the statistical probability that strong out-of-band signals
will ride down the IF and overload downstream stages. 

Cheers for now, 73,
Adam VA7OJ/AB4OJ



Scanned for viruses by Blue Coat
http://www.WinProxy.com/


More information about the Yaesu mailing list