[Elecraft] K-3 Roofing filter comment

[wa9fvp]

Actually the AGC is generated by the DSP in software.  The signal VIFGAIN1
coming from a D to A converter (AD5302A) if fed back to the IF amplifier to
control the receiver's gain.  After the DSP filter reduces the bandwidth,
the AGC is adjusted by the DSP.  It's all done using mathematical
calculations. 

You can have a situation where the DSP filter is narrower then the roofing
filter but if the DSP engineer does his job, the unwanted signal will be
outside the DSP filter bandwidth.  The third order products will be at a
minimum and the AGC will not be affected. 

-----
Jack WA9FVP
Willco Electronics
--
View this message in context: http://elecraft.365791.n2.nabble.com/K-3-Roofing-filter-comment-tp6576237p6585872.html
Sent from the Elecraft mailing list archive at Nabble.com.