Re: [Discuss-gnuradio] Ettus N210 GMSK 9600

I do have that fix in place. I added the tag_debug for time_est. I'm not sure which value causes the error, but I see:

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 37840 Source: corr_est_cc0 Key: time_est Value: 0.363934

Offset: 37851 Source: corr_est_cc0 Key: time_est Value: -0.478847

Offset: 37871 Source: corr_est_cc0 Key: time_est Value: 0.226898

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 38211 Source: corr_est_cc0 Key: time_est Value: 0.379335

Offset: 38341 Source: corr_est_cc0 Key: time_est Value: -0.205535

Offset: 38351 Source: corr_est_cc0 Key: time_est Value: 0.129156

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 38981 Source: corr_est_cc0 Key: time_est Value: -0.0236422

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 39911 Source: corr_est_cc0 Key: time_est Value: -0.270991

Offset: 39921 Source: corr_est_cc0 Key: time_est Value: -0.381561

----------------------------------------------------------------------

thread[thread-per-block[17]: <block msk_timing_recovery_cc (10)>]: mmse_fir_interpolator_cc: imu out of bounds.

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 40221 Source: corr_est_cc0 Key: time_est Value: 0.0493416

Offset: 40231 Source: corr_est_cc0 Key: time_est Value: -0.022505

Offset: 40271 Source: corr_est_cc0 Key: time_est Value: 0.305939

Offset: 40292 Source: corr_est_cc0 Key: time_est Value: 0.130002

Offset: 40302 Source: corr_est_cc0 Key: time_est Value: -1.17942

Offset: 40322 Source: corr_est_cc0 Key: time_est Value: 0.117131

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 41311 Source: corr_est_cc0 Key: time_est Value: 0.338163

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 41452 Source: corr_est_cc0 Key: time_est Value: -0.18281

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 41522 Source: corr_est_cc0 Key: time_est Value: 0.491506

Offset: 41651 Source: corr_est_cc0 Key: time_est Value: 0.151281

Offset: 41942 Source: corr_est_cc0 Key: time_est Value: 0.0604672

Offset: 41952 Source: corr_est_cc0 Key: time_est Value: -0.191828

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 42582 Source: corr_est_cc0 Key: time_est Value: -0.281153

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 44901 Source: corr_est_cc0 Key: time_est Value: -0.495743

Offset: 44911 Source: corr_est_cc0 Key: time_est Value: 0.380034

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 45742 Source: corr_est_cc0 Key: time_est Value: -0.123585

Offset: 46022 Source: corr_est_cc0 Key: time_est Value: 0.0915709

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 46171 Source: corr_est_cc0 Key: time_est Value: 0.0782069

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 46763 Source: corr_est_cc0 Key: time_est Value: 0.0567441

Offset: 46773 Source: corr_est_cc0 Key: time_est Value: -1.31157

Offset: 46842 Source: corr_est_cc0 Key: time_est Value: -0.484528

----------------------------------------------------------------------

Tag Debug: corr_est

Input Stream: 00

Offset: 47372 Source: corr_est_cc0 Key: time_est Value: -0.388704

----------------------------------------------------------------------

On Thu, Mar 24, 2016 at 5:26 PM, Andy Walls <address@hidden> wrote:

From:
Tom Golden

Date:
Thu, 24 Mar 2016 13:07:57 -0600

________________________________________________________________________
>Sorry - I was attempting to be courteous to other users.

No worries. It's just that others can't learn and contribute, if the
conversation goes off list. Also, I charge for private consulting. ;)

If other users don't like on-topic posts, then I suppose they'll be
unsubscribing shortly anyway.

>I added a Correlation Estimator before the MSK Timing Recover looking
>for 0x7E (the start frame byte for AX.25). I think it found it (based
>on the image below) - unfortunately when it hits, execution stops with
>the error:

>thread[thread-per-block[9]: <block msk_timing_recovery_cc (8)>]:
>mmse_fir_interpolator_cc: imu out of bounds.

Ah crud, that bug.

OK, in the MSK timing recovery block, "mu" is an inter-sample distance
in the range [0.0, 1.0), which gets passed to the mmse_fir_interpolator
to interpolate between samples.

The MSK timing recovery block doesn't do enough sanity checking on the
"time_est" tag payload value produced by the corr_est block, so it
screws up its internal value of "mu" and then bombs.

Does your version of gnuradio have this fix in place:
https://github.com/gnuradio/gnuradio/blob/master/gr-digital/lib/msk_timing_recovery_cc_impl.cc#L150
?

If you run the flowgraph again, can you put a tag_debug block on the
output of the corr_est block to dump out the values of the "time_est"
tag. I'm curious as to what value of "time_est" coming out of the
corr_est block may be tripping up the msk_timing_recovery_block.

-Andy

From:	Tom Golden
Subject:	Re: [Discuss-gnuradio] Ettus N210 GMSK 9600
Date:	Fri, 25 Mar 2016 08:56:16 -0600