[hpsdr] ANAN200D RX1/RX2 Phase Coherent and Phase difference (2)

[Scott Traurig]

Bryan's method appears to have a lot of merit.

Although the DDCs may not run with the same phase word, at least they are
effectively phase locked and therefore coherent (with some random but
unchanging phase differential) during operation. So although there is a
manual calibration that needs to take place every time the DDCs are
re-instantatiated/initialized (or whatever the correct word is), with
Bryan's method the output IQ streams remain similarly coherent at the VAC
interface. If you need to obtain them from the separate VAC1 and VAC2
interfaces they will not be that way. In addition, I do not believe that
MAP65 or Linrad (for example) can handle data coming from two different
devices. Placing the RX2 data on a channel 3 and 4 of the VAC1 interface
will also solve that problem for those highly specialized users and uses.

73!

Scott/w-u-2-o


On Sat, Jan 28, 2017 at 3:31 PM, Warren C. Pratt <warren at wpratt.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi Bryan,
>
> As I understand, I think the intent is to have diversity ENABLED so that
> both DDCs run with the same phase word.  There are, of course, ways that
> Joe's idea of getting the two streams out (with diversity enabled) could be
> done.  They would, however, require some architectural change in the
> software.
>
> 73,
>
> Warren  NR0V
>
>
> On 1/28/2017 12:19 PM, Bryan Rambo wrote:
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Hi Warren and All,
>>
>> The following is probably a really stupid suggestion:  But couldn't you
>> just
>> disable diversity and send both IQ streams (RX1 & RX2) out through VAC in
>> a
>> four channel stream?
>>
>> I'm working on a patch right now for another ham that does this.  What do
>> you think???
>>
>> 73, Bryan W4WMT
>>
>
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