[Elecraft] Re: AGC Design of the K3

[Larry Phipps]

Wayne, as you know from my private correspondence, I think the variable 
filters are the best way to go on this, as there are just not enough 
slots to get to an adequate level of protection for anyone who uses a 
lot of modes. Another example of thinking outside the box. I LOVE the 
use of the term "tracking filter", BTW. You should use that term in all 
future references to the new filters. Any idea when they might be available?

73,
Larry N8LP



> Date: Mon, 12 May 2008 19:36:16 -0700
> From: wayne burdick <n6kr at elecraft.com>
> Subject: [Elecraft] Re: AGC Design of the K3
> To: Shane White <shanewh at gmail.com>
> Cc: elecraft at mailman.qth.net
> Message-ID: <69c458cd2a969e805108281936a5dbef at elecraft.com>
> Content-Type: text/plain; charset=US-ASCII; format=flowed
>
> The K3 selects a filter based on the user's WIDTH setting, which 
> usually varies with the mode of operation. Typically you might select 
> 50 Hz to 1000 Hz WIDTH while using CW mode. We offer several crystal 
> filters in this range (200, 250, 400, 500, and 1000), and if you have 
> more than one installed, the K3 will select the optimal one 
> automatically.
>
> The idea of a variable-passband crystal filter is that it could replace 
> two or more fixed-bandwidth filters. For example, if we made one with a 
> BW of about 200-500 Hz, it could replace up to four crystal filters (in 
> practice, it would be replacing two or three at most). This would free 
> up one or two slots for other fixed- or variable-bandwidth SSB filters.
>
> Since this variable-passband filter has 8 steps of bandwidth, we can 
> optimize automatically it to be equal to or just a bit higher than the 
> selected DSP bandwidth (i.e., the WIDTH control setting). So you could 
> think of them as "DSP-tracking crystal filters."
>
> Wayne
> N6KR