diff options
| author | Tom Rondeau <trondeau@vt.edu> | 2012-09-09 14:34:08 -0400 |
|---|---|---|
| committer | Tom Rondeau <trondeau@vt.edu> | 2012-09-09 14:40:31 -0400 |
| commit | d857caa7f1a703731c69fdcdd1fdb6c7d0a99a7c (patch) | |
| tree | 871ca65b4ca1399ff2bb993360d6e434e1917e4f /gr-digital/lib/cma_equalizer_cc_impl.cc | |
| parent | 43eaedf41a4281370cb71cf0bddf891d3867698c (diff) | |
digital: Fixes LMS and CMA equalizers.
filter: updated fir_filter_* by adding a method that allows the update of a single tap in the filter in a way that propagates to all of the aligned tap vectors. Mostly to support the adaptive equalizers.
Diffstat (limited to 'gr-digital/lib/cma_equalizer_cc_impl.cc')
| -rw-r--r-- | gr-digital/lib/cma_equalizer_cc_impl.cc | 60 |
1 files changed, 52 insertions, 8 deletions
diff --git a/gr-digital/lib/cma_equalizer_cc_impl.cc b/gr-digital/lib/cma_equalizer_cc_impl.cc index fca7c0c6e5..e4e6c56466 100644 --- a/gr-digital/lib/cma_equalizer_cc_impl.cc +++ b/gr-digital/lib/cma_equalizer_cc_impl.cc @@ -30,6 +30,8 @@ namespace gr { namespace digital { + using namespace filter::kernel; + cma_equalizer_cc::sptr cma_equalizer_cc::make(int num_taps, float modulus, float mu, int sps) { @@ -43,38 +45,80 @@ namespace gr { gr_make_io_signature(1, 1, sizeof(gr_complex)), gr_make_io_signature(1, 1, sizeof(gr_complex)), sps), - filter::kernel::fir_filter_ccc(sps, std::vector<gr_complex>(num_taps, gr_complex(0,0))), + fir_filter_ccc(sps, std::vector<gr_complex>(num_taps, gr_complex(0,0))), + d_new_taps(num_taps, gr_complex(0,0)), d_updated(false), d_error(gr_complex(0,0)) { set_modulus(modulus); set_gain(mu); if(num_taps > 0) - d_taps[0] = 1.0; - set_taps(d_taps); + d_new_taps[0] = 1.0; + fir_filter_ccc::set_taps(d_new_taps); - set_history(num_taps+1); + set_history(num_taps); } cma_equalizer_cc_impl::~cma_equalizer_cc_impl() { } + void + cma_equalizer_cc_impl::set_taps(const std::vector<gr_complex> &taps) + { + d_new_taps = taps; + d_updated = true; + } + + std::vector<gr_complex> + cma_equalizer_cc_impl::taps() const + { + return d_taps; + } + + gr_complex + cma_equalizer_cc_impl::error(const gr_complex &out) + { + gr_complex error = out*(norm(out) - d_modulus); + float re = gr_clip(error.real(), 1.0); + float im = gr_clip(error.imag(), 1.0); + return gr_complex(re, im); + } + + void + cma_equalizer_cc_impl::update_tap(gr_complex &tap, const gr_complex &in) + { + // Hn+1 = Hn - mu*conj(Xn)*zn*(|zn|^2 - 1) + tap -= d_mu*conj(in)*d_error; + } + int cma_equalizer_cc_impl::work(int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) { - gr_complex *in = (gr_complex *)input_items[0]; + const gr_complex *in = (const gr_complex *)input_items[0]; gr_complex *out = (gr_complex *)output_items[0]; - int j = 0, k, l = d_taps.size(); + if(d_updated) { + d_taps = d_new_taps; + set_history(d_taps.size()); + d_updated = false; + return 0; // history requirements may have changed. + } + + int j = 0; + size_t k, l = d_taps.size(); for(int i = 0; i < noutput_items; i++) { out[i] = filter(&in[j]); // Adjust taps d_error = error(out[i]); - for (k = 0; k < l; k++) { - update_tap(d_taps[l-k-1], in[j+k]); + for(k = 0; k < l; k++) { + // Update tap locally from error. + update_tap(d_taps[k], in[j+k]); + + // Update aligned taps in filter object. + fir_filter_ccc::update_tap(d_taps[k], k); } j += decimation(); |