Lyle, > > 4) Is there a table that provides a dBm equivalent of each > > of the threshold values? Or alternatively are the values > > on the Clifton Labs site correct? > > > > (2 -117 dBm > > 3 -110.5 dBm > > 4 -105 dBm > > 5 -103.5 dBm > > 6 -102.5 dBm > > 7 -101 dBm > > 8 -99 dBm ) > > > > There is no available table, and Jack's measurements were > accurate at the time they were made for the then-current > firmware release.
Assuming that the threshold values have not changed in a major way since Jack's measurements, would it be possible to extend the range of threshold values - say to AGC THR=016 at about -80dBm (assuming 2 dB per step)? Such a change would put the K3 more in line with the K2 as measured by Jack Smith ... as well as numbers reported by Sherwood for the FT-1000D, FT-1000MP and even the IC-7600. 73, ... Joe, W4TV > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Lyle Johnson > Sent: Sunday, February 07, 2010 2:21 PM > To: Guy Olinger K2AV > Cc: [email protected] > Subject: Re: [Elecraft] K3 DSP AGC Question > > > > > Some follow-on questions: > > > > 1) When you say "The DSP outputs a voltage to control the > IF gain of > > the radio." are you referring to VIFGAIN1 input to U3B on the RF > > board? > > > > Yes. > > 2) Assuming so, is there anything that influences the voltage on > > VIFGAIN1 other than on behalf of the RF gain pot, and is > the voltage > > appearing at VFGAIN1 on behalf of the RF gain pot "processed" away > > from a linear replication of the pot wiper voltage? > > > Without staring at the DSP code to verify the veracity of my reply, I > recall that the RF Gain control is the only thing that > currently drives > the VIFGAIN1 voltage. Subject to change, of course, since it > is a DSP > firmware function. And yes, the value read from the pot is > processed by > the DSP on its way to becoming VIFGAIN1. Again, the > algorithm applied > is subject to change. > > 3) The hardware AGC appears to have fixed slope, attack and decay > > constants. What would be the DSP slope and decay config > constants to > > mimic the hardware AGC constants? > > > Correct as to the first, and I think there may be that there are no > settings that exactly mimic the HAGC. Their purposes are quite > different. To the DSP, influences of the HAGC voltage on the > received > signal are treated no differently than changes in propagation. > > 4) Is there a table that provides a dBm equivalent of each of the > > threshold values? Or alternatively are the values on the > Clifton Labs > > site correct? > > > > ( 2 -117 dBm > > 3 -110.5 dBm > > 4 -105 dBm > > 5 -103.5 dBm > > 6 -102.5 dBm > > 7 -101 dBm > > 8 -99 dBm ) > > > > There is no available table, and Jack's measurements were accurate at > the time they were made for the then-current firmware release. > > 73, > > Lyle KK7P > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
