I am not sure I understand the meaning behind the 5-bit channel
entry:
I thought that this might refer to channels within the total
bandwidth of the incoming / outgoing signals...you said that these
are "logically independent of the others" samples, and I was
thinking this was referring perhaps to frequency division of some
sort (like bin values in an FFT). Could you help me understand what
you mean by channels here?
It's just away to think about how to route samples to/from the A/D's
and D/A's. (5-bits is probably overkill, but I'm dreaming of a day
when Matt provides us h/w that can do 16x16 MIMO.) If you're running
two daughterboards, you may want to send an independent stream of
samples to each. Now, it may be that you want the samples interleaved
(minimizing latency) on a single logical channel, but it also may be
that you are running the two daughterboards fully independently of
each other -- you could imagine them running with different interp or
decim rates (not implemented currently.) In that case, one stream of
samples would be assigned to Chan 0, the other to Chan 1.
Also, I was wondering about Timestamping...In the document you wrote
"If a packet reaches the head of the transmit queue, and the current
time is later than the timestamp, an error is assumed to have
occurred
and the packet is discarded."
so, if the packet that is ready to be transmitted is early, then it
should be discarded? Maybe I am misunderstanding how the time stamp
is going to be done.
Using wall clock time for illustrative purposes, if the
current time is 8:30 and the packet timestamp says 8:25, the packet
got here late, and we drop it ;)