diff options
Diffstat (limited to 'gnuradio-core/src/lib/general')
| -rw-r--r-- | gnuradio-core/src/lib/general/gr_fll_band_edge_cc.h | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/gnuradio-core/src/lib/general/gr_fll_band_edge_cc.h b/gnuradio-core/src/lib/general/gr_fll_band_edge_cc.h index 178e18f3e..db060793e 100644 --- a/gnuradio-core/src/lib/general/gr_fll_band_edge_cc.h +++ b/gnuradio-core/src/lib/general/gr_fll_band_edge_cc.h @@ -48,12 +48,12 @@ class gri_fft_complex; * * The FLL works by filtering the upper and lower band edges into x_u(t) and x_l(t), respectively. * These are combined to form cc(t) = x_u(t) + x_l(t) and ss(t) = x_u(t) - x_l(t). Combining - * these to form the signal e(t) = Re{cc(t) \times ss(t)^*} (where ^* is the complex conjugate) + * these to form the signal e(t) = Re{cc(t) \\times ss(t)^*} (where ^* is the complex conjugate) * provides an error signal at the DC term that is directly proportional to the carrier frequency. * We then make a second-order loop using the error signal that is the running average of e(t). * * In theory, the band-edge filter is the derivative of the matched filter in frequency, - * (H_be(f) = \frac{H(f)}{df}. In practice, this comes down to a quarter sine wave at the point + * (H_be(f) = \\frac{H(f)}{df}. In practice, this comes down to a quarter sine wave at the point * of the matched filter's rolloff (if it's a raised-cosine, the derivative of a cosine is a sine). * Extend this sine by another quarter wave to make a half wave around the band-edges is equivalent * in time to the sum of two sinc functions. The baseband filter fot the band edges is therefore @@ -93,7 +93,11 @@ class gr_fll_band_edge_cc : public gr_sync_block /*! * Build the FLL - * \param taps (vector/list of gr_complex) The taps of the band-edge filter + * \param samps_per_sym (float) number of samples per symbol + * \param rolloff (float) Rolloff (excess bandwidth) of signal filter + * \param filter_size (int) number of filter taps to generate + * \param alpha (float) Alpha gain in the control loop + * \param beta (float) Beta gain in the control loop */ gr_fll_band_edge_cc(float samps_per_sym, float rolloff, int filter_size, float alpha, float beta); |