[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
> G0MGX
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