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From: | Steven Knudsen |
Subject: | [Discuss-gnuradio] Fwd: Correlation Estimator in 3.7.10 |
Date: | Tue, 27 Sep 2016 09:37:06 -0600 |
Alright, after some more thought I believe I understand what is going on. By looking at the cross-correlation power for the current input samples, the threshold can be calculated as a desired false alarm rate. An “arbitrary” threshold can be set independently of the received signal power. Unfortunately, for the test_corr_est.grc example, you just can’t set the threshold high enough to avoid false alarms. I tried the CE block with up to 0.999999 for the threshold and it was still a mess, though much better. That said, for my own application/flowgraph, setting the CE block threshold to 0.9999 appears to work. I can set as “low” as 0.999, but that’s it. This makes me wonder why bother to have a threshold parameter at all? Maybe just set the calculated d_pfa value to 10 or something and be done with it. Of course, we all hate magic numbers, and so doing would introduce a second number to the algorithm (the first is a multiplier of 4 in the peak thresholding logic). Thanks for your patience… Steven Knudsen, Ph.D., P.Eng. www. techconficio.ca Von einem gewissen Punkt an gibt es keine Rückkehr mehr. Dieser Punkt ist zu erreichen. - Franz Kafka
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