HI Joe & Steve,
one quick win might be to implement a more CPU intensive decode at the
Rx DF +/- a few Hertz when clicking the "Decode" button or double
clicking the waterfall. I believe most of the logic to drive this is
already in place.
73
Bill
G4WJS.
On 30/06/2017 15:34, Steven Franke wrote:
Joe,
Were these results obtained with 40 iterations for bp and norder = 3 for
signals at or within 10 Hz of nfqso? If so, it might be interesting to see how
the numbers would change if you dropped back to norder=2 for all signals.
Steve
On Jun 30, 2017, at 9:25 AM, Joe Taylor<[email protected]> wrote:
Hi all,
Thanks for a busy ~20 hours of many people testing FT8. I now have accumulated
a directory with 527 *.wav files, each of which has at least one visible FT8
signal. The files were recorded at K1JT at either 14.079 or 50.313 MHz.
Running the r7753 stand-alone slow-mode decoder jt9[.exe] on this collection of
files produces 574 valid decodes and 0 false decodes with total execution time
39.8 s. The average time to process a 15 s Rx sequence on this machine (Core
i7-6700 @ 3.4 GHz) is thus 39.8/527 = 0.076 s. Not bad!
Here's the detailed execution-time breakdown from timer.out:
Name Time Frac dTime dFrac Calls
----------------------------------------------------------
jt9 39.828 1.00 0.734 0.02 1
read_wav 0.121 0.00 0.121 0.00 27404
decft8 38.973 0.98 0.133 0.00 527
sync8 4.191 0.11 4.191 0.11 527
ft8b 34.648 0.87 0.051 0.00 2821
bpd174 1.480 0.04 1.480 0.04 2821
osd174 33.117 0.83 33.117 0.83 2210
----------------------------------------------------------
39.828 1.00
Note that 83% of the execution time is spent in routine osd174, 11% in sync8,
and 4% in bpd174 (a contraction for subroutine name bpdecode174).
It turns out that only 14 of the 574 decodes were produced by osd174, the "ordered
statistics" decoder. The rest came from bpd174. With osd174 deactivated, timer.out
looks like this:
Name Time Frac dTime dFrac Calls
----------------------------------------------------------
jt9 6.641 1.00 0.891 0.13 1
read_wav 0.168 0.03 0.168 0.03 27404
decft8 5.582 0.84 0.094 0.01 527
sync8 3.887 0.59 3.887 0.59 527
ft8b 1.602 0.24 0.109 0.02 2821
bpd174 1.492 0.22 1.492 0.22 2821
osd174 0.000 0.00 0.000 0.00 2210
----------------------------------------------------------
6.641 1.00
Now the average execution time for a 15 s Rx sequence is just 13 ms!
We need to keep decoding time very short -- say, well under 1 s -- so that
auto-sequencing, if not the human operator, can select proper responses to received
messages. Fortunately, we already have good baseline performance -- and we have a number
of "knobs" to play with.
-- Joe, K1JT
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