Hi Stefan
On 11/30/2012 11:00 AM, Stefan Schäfer wrote:
Hi Joe/K1JT,
A general question to the NB: What do you think about its performance in
the current state? Normally NB is disabled when starting the program.
Applying a NB to "remove" QRN makes a big effect on LF, you know.
Is there an estimation like 2 dB improvement or so?
So far I have spent very little time testing or optimizing the WSJT-X
noise blanker.
Here are some relevant examples from a week ago on 80 meters. The same
recorded raw data has been decoded twice using WSJT-X r2788. Everything
was the same for the two cases, except for switching NB OFF or ON.
UTC Sync dB DT Freq Drift Message
-------------------------------------------------
2156 5 -26 0.3 1349. -1 K1JT G0MGM -09 (NB OFF)
2158 4 -25 0.2 1349. 0 K1JT G0MGM RRR (NB OFF)
2156 9 -22 0.3 1349. -1 K1JT G0MGM -09 (NB ON)
2158 4 -22 0.2 1349. 0 K1JT G0MGM RRR (NB ON)
2200 4 -22 0.1 1346. 1 K1JT I3VWK JN55 (NB OFF)
2200 5 -21 0.1 1346. 1 K1JT I3VWK JN55 (NB ON)
Although there's some suggestion that the present noise blanker can
improve S/N by 1 to 4 dB, this is hardly a definitive result.
If you have some useful example files with a marginal JT9 signal and
heavy QRN, please send them along! I may find some time to work on the
noise blanker soon.
-- 73, Joe, K1JT
PS: alas, I listened for your LF signal on 137.42 last night, but did
not copy anything.
|
