Hi Tom, Thanks for your help. I've adapted the sample rate of the result coming out of the low-pass filter now. However, if I decimate much further, my signal becomes a bit too weak I think. New chart: http://imgur.com/mbt288s,etHbYLT#0
New result: http://imgur.com/mbt288s,etHbYLT#1 Is this a better approach? The initial error still persists though. Regards From: [email protected] To: [email protected] Date: Thu, 20 Aug 2015 09:09:42 +0200 CC: [email protected] Subject: Re: [Discuss-gnuradio] GnuRadio: Clock Recovery MM: imu out of bounds Hi Tom, Thanks for your answer. That's indeed something that I need to think about more. However, as I understand it, the samples per symbol rate is equal to (samp_rate / data_rate). My sample rate is 500k, and my data rate (i think) is only around 100 or 200. See this figure of my (cleaned) signal: http://imgur.com/8pNqCop You see that it takes approximately 10 ms to transmit one symbol. This means 100 symbols per second. As I have 500k samples per second, this means 5k samples per symbol, right? However, I have tried setting the samples per symbol to 4, just to try, and the 'out of bounds' error still persists. Regards, Michael From: [email protected] Date: Wed, 19 Aug 2015 09:41:19 -0400 Subject: Re: [Discuss-gnuradio] GnuRadio: Clock Recovery MM: imu out of bounds To: [email protected] CC: [email protected] On Wed, Aug 19, 2015 at 2:51 AM, Michael B <[email protected]> wrote: I have created a flowgraph, based on an example of Michael Ossmann, which takes in a signal, and should output bits.I need to use the clock recovery MM block, which I do not fully understand yet. However, after reading some blogposts, I am quite sure that I can leave most of the settings default, except for the Omega one. Here's my flowgraph: http://imgur.com/pHRXnZu When running this flowgraph, it gives me the following error: thread[thread-per-block[5]:<block clock_recovery_mm_ff (9)>]: mmse_fir_interpolator_ff: imu out of bounds. While searching, I stumbled upon this piece of code in the source of GnuRadio: int imu = (int)rint(mu * NSTEPS); if((imu < 0) || (imu > NSTEPS)) { throw std::runtime_error("mmse_fir_interpolator_ff: imu out of bounds.\n"); } So, I suspect it is not due to my Omega setting (which might be wrong, I have to play with that setting), but that it is due to my Mu setting, which is just the default (0.5). However, I understand that Mu needs to be between 0 and 1, so I do not really understand what the problem is. Anyone who does?Environment details:GNU Radio Companion 3.7.7.1Running a GNU Radio live DVD in a virtual machine (VirtualBox 4.2.12) on Windows 7.Using Volk machine: ssse3_64 Michael, I don't have an answer, but I can say where you're doing something wrong. You're samples/symbol (samp_per_sym) is definitely /not/ 2.5k. That's a massively oversampled signal and can't be right. You need to think what's the sampling rate of the system? What's the symbol rate of my signal? That will tell you the samples/symbol you need. It should small, like 2 or 4. Tom _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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