[minima] Re: Linear Output Filter Switching

  • From: Wayne McFee <nb6m@xxxxxxx>
  • To: "minima@xxxxxxxxxxxxx" <minima@xxxxxxxxxxxxx>
  • Date: Fri, 31 Jan 2014 16:10:28 -0800

Hi Mark,

If the three outputs were set up as you suggest, a Picaxe chip could be 
programmed to control either individual relay driver transistors or a relay 
driver chip like the 2903(?).  

I've been using that arrangement for filter selection  in a homebrew rig.

Or, if one of those output lines could be programmed to output a stepped 
voltage such as that provided by the FT817 for bandswitching info, that makes 
the programming even easier. 

Wayne NB6M

> On Jan 31, 2014, at 1:24 PM, Mark G0MGX <mark.g0mgx@xxxxxxxxx> wrote:
> Farhan & Team,
> I can see that we have provision in the schematic for 3 digital outputs for 
> band selection, but can only see one of these (BAND_HI - pin 11 - Arduino D5) 
> being used within the function "setBandswitch". It is this function that 
> currently selects the LPF used based on frequency.
> We could set the state of the three outputs based on frequency something like 
> this:
> <Filter Ideas.png>
> But someone far cleverer than I would need to explain how to create relay 
> on/off switching based on the logic states of  the three lines - I have no 
> idea how to do that!
> If we were to implement something like this was the intention to use these 
> additionally switched filters in RX as well as TX?
> I would be interested in your thoughts and ideas on how you saw this working 
> before I head down the wrong road with my construction!
> Many thanks,
> Mark

Other related posts: