diff options
Diffstat (limited to 'gr-digital/lib/clock_tracking_loop.cc')
| -rw-r--r-- | gr-digital/lib/clock_tracking_loop.cc | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/gr-digital/lib/clock_tracking_loop.cc b/gr-digital/lib/clock_tracking_loop.cc index 0eaa8f29cf..ed8b3efe05 100644 --- a/gr-digital/lib/clock_tracking_loop.cc +++ b/gr-digital/lib/clock_tracking_loop.cc @@ -126,8 +126,20 @@ namespace gr { // Integral arm of PI filter d_avg_period = d_avg_period + d_beta * error; + // Limit the integral arm output here, as a large negative + // error input can lead to a negative d_avg_period, which + // will cause an infitine loop in the phase wrap method. + period_limit(); + // Proportional arm of PI filter and final sum of PI filter arms d_inst_period = d_avg_period + d_alpha * error; + // Limit the filter output here, for the errant case of a large + // negative error input, that can lead to a negative d_inst_period, + // which results in an incorrect phase increment, as it is assumed + // to be moving forward to the next symbol. + if (d_inst_period <= 0.f) + d_inst_period = d_avg_period; + // Compute the new, unwrapped clock phase d_phase = d_phase + d_inst_period; } |