[hpsdr] Alex Filter Switching Frequencies

[Warren C. Pratt]

I second Scotty's suggestion.  It's difficult to in advance anticipate all
future needs and situations.  As a general rule, I'd like to see as much
hardware control as practical exposed to the software.

Scotty's suggestion is also very convenient in that it allows existing
software to work.

73,
Warren  NR0V

-----Original Message-----
From: hpsdr-bounces at lists.openhpsdr.org
[mailto:hpsdr-bounces at lists.openhpsdr.org] On Behalf Of Scott Cowling
Sent: Friday, September 09, 2011 10:04 AM
To: hpsdr at lists.openhpsdr.org
Subject: Re: [hpsdr] Alex Filter Switching Frequencies

***** High Performance Software Defined Radio Discussion List *****

Hi Phil,

I suggest that we implement #2 (using Lyle's suggested frequencies), 
which would fix the "early switching" problem and keep MARS operators happy.

We can then add an additional bit to the C0 command 0b0001001x in bit 
6 of byte C2 called

"Alex - Enable manual filter selection independent of frequency 
(0=disable, 1=enable)"

Then bytes C3 and C4 can contain the filter selections.  If 16 bits 
is not enough, then we can add another C0 command to select the filters.

In the Mercury code, when the "manual filter enable bit" (which is 
normally always zero in current implementations) is set high, you 
prevent the frequency from selecting the filter.

As long as the "manual filter enable bit" is zero, the manual 
selection bits in C3 and C4 (or the selection bits in the additional 
C0 command) are ignored and filter selection is done as it is now.

This would allow all existing software to work as-is, but allow new 
software (or updates to existing software) to set the filters 
manually if desired.

You could even put a button on the software GUI for "auto/manual" 
select of the filters.

I can write up an addendum to the USB protocol document to cover this 
if that is the direction we decide to go.

73,
Scotty WA2DFI



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