AGC is instant and dynamic, and does not vary RF gain, PRE/ATT settings which are static unless the user changes them. RF gain, PRE, and ATT result in numeric "advice" to the CPU, rather than being in direct control of a circuit or device as in an analog receiver. The CPU in turn drives the actual circuit devices from it's many outputs. There are many uses for this indirect linking.
At issue is that the main smart AGC is digital signal processing, and is *AFTER* the analog to digital conversion (ADC). The RF gain (which is really IF gain), PRE and ATT are before the ADC, and improperly setting those can squeeze the noise into the high numerical range in the conversion or even engage the defensive hardware AGC which is better off not being engaged. The defensive AGC is analog, has no smarts, and unfortunately must reduce signal-to-noise in doing its job of preventing ADC input overload. Those who understand how the rig works will throttle back the pre-digital controls to where noise is at most moderately loud to obtain best operation of digital features. What I am suggesting is that in an "AUTO" novice mode a slow (rate of human turning the RF gain) throttling back can be set (and then left alone) by the radio for those who are not into the theory and do not recognize the source of their complaints as being caused/worsened by their misadjustment of RF gain, PRE and ATT. Leaving PRE on and RF gain at max on all bands regardless causes the digital AGC to increase or reduce the noise to the same level as the wanted signal in pauses. This reduces the effectiveness of the NR algorithms. Those who ride their own RF gains would not be using this. 73, Guy. On Fri, Jul 9, 2010 at 12:37 PM, Wes Stewart <[email protected]> wrote: > That sounds amazingly like automatic gain control, something I thought you > "ride the r-f gain control" types studiously avoided. > > > --- On *Fri, 7/9/10, Guy Olinger K2AV <[email protected]>* wrote: > > > Or, perhaps, sinisterly, simply make this happen in the firmware > without telling anyone. > > > ______________________________________________________________ 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
