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From: | Marcus Müller |
Subject: | Re: [Discuss-gnuradio] Clock Recovery MM documentation |
Date: | Fri, 31 Jul 2015 19:50:47 +0200 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 |
Hi Tom, why do I have to advertise the PFB approach? Arguing against Mueller & Müller feels strange. Anyway: Mueller & Müller in the classical, real valued approach [1, eq (49), p. 524] in its core is with being the timing estimate , being the input samples, and the decisions (in our case, -1/+1 [2], so ). Assume timing is correct, ie. , but we have fading so that ; then regardless of , the term , and hence Now, is exactly the decision we don't want to put much trust in, because it's a symbol decision with especially bad . Effectively, you get the bit error probability increase as a factor to your timing error probability density, as if things weren't bad enough! PFB is cooler because
Marcus [1] http://2n3904.net/library/MM_Clock_Recovery.pdf [2] https://github.com/gnuradio/gnuradio/blob/master/gr-digital/lib/clock_recovery_mm_ff_impl.cc#L83 On 31.07.2015 01:06, Tom Rondeau wrote:
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