[Commit-gnuradio] r8198 - gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl

[trondeau]

Author: trondeau
Date: 2008-04-15 11:06:46 -0600 (Tue, 15 Apr 2008)
New Revision: 8198

Modified:
   gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm.py
   gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_receiver.py
   gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_sync_pn.py
Log:
Adjusting structure a bit to redistribute responsibilities. This does not 
change the behavior or performance at all. The sync. block only calculates the 
frequency and timing signals and now outputs the fine frequency adjustment 
signal from output 0 and the timing signal for the start of the packet from 
output 1.

Modified: gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm.py
===================================================================
--- gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm.py  
2008-04-15 05:05:46 UTC (rev 8197)
+++ gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm.py  
2008-04-15 17:06:46 UTC (rev 8198)
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright 2006,2007 Free Software Foundation, Inc.
+# Copyright 2006,2007,2008 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -197,10 +197,11 @@
         self._snr = options.snr
 
         # Use freq domain to get doubled-up known symbol for correlation in 
time domain
+        zeros_on_left = int(math.ceil((self._fft_length - 
self._occupied_tones)/2.0))
         ksfreq = known_symbols_4512_3[0:self._occupied_tones]
         for i in range(len(ksfreq)):
-            if(i&1):
-                ksfreq[i] = 0        
+            if((zeros_on_left + i) & 1):
+                ksfreq[i] = 0
 
         # hard-coded known symbols
         preambles = (ksfreq,)

Modified: 
gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_receiver.py
===================================================================
--- gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_receiver.py 
2008-04-15 05:05:46 UTC (rev 8197)
+++ gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_receiver.py 
2008-04-15 17:06:46 UTC (rev 8198)
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright 2006, 2007 Free Software Foundation, Inc.
+# Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -62,7 +62,7 @@
        gr.hier_block2.__init__(self, "ofdm_receiver",
                                gr.io_signature(1, 1, gr.sizeof_gr_complex), # 
Input signature
                                 gr.io_signature2(2, 2, 
gr.sizeof_gr_complex*occupied_tones, gr.sizeof_char)) # Output signature
-
+        
         bw = (float(occupied_tones) / float(fft_length)) / 2.0
         tb = bw*0.08
         chan_coeffs = gr.firdes.low_pass (1.0,                     # gain
@@ -75,39 +75,56 @@
         win = [1 for i in range(fft_length)]
 
         zeros_on_left = int(math.ceil((fft_length - occupied_tones)/2.0))
-        zeros_on_right = fft_length - occupied_tones - zeros_on_left
-        ks0 = zeros_on_left*[0.0,]
-        ks0.extend(ks[0])
-        ks0.extend(zeros_on_right*[0.0,])
+        ks0 = fft_length*[0,]
+        ks0[zeros_on_left : zeros_on_left + occupied_tones] = ks[0]
         
+        ks0 = fft.ifftshift(ks0)
         ks0time = fft.ifft(ks0)
         # ADD SCALING FACTOR
         ks0time = ks0time.tolist()
-        
+
         SYNC = "pn"
         if SYNC == "ml":
-            self.ofdm_sync = ofdm_sync_ml(fft_length, cp_length, snr, logging)
+            nco_sensitivity = -1.0/fft_length                             # 
correct for fine frequency
+            self.ofdm_sync = ofdm_sync_ml(fft_length, cp_length, snr, ks0time, 
logging)
         elif SYNC == "pn":
+            nco_sensitivity = -2.0/fft_length                             # 
correct for fine frequency
             self.ofdm_sync = ofdm_sync_pn(fft_length, cp_length, logging)
         elif SYNC == "pnac":
+            nco_sensitivity = -2.0/fft_length                             # 
correct for fine frequency
             self.ofdm_sync = ofdm_sync_pnac(fft_length, cp_length, ks0time)
         elif SYNC == "fixed":
+            nco_sensitivity = -2.0/fft_length                             # 
correct for fine frequency
             self.ofdm_sync = ofdm_sync_fixed(fft_length, cp_length, logging)
-                        
+
+        # Set up blocks
+
+        self.nco = gr.frequency_modulator_fc(nco_sensitivity)         # 
generate a signal proportional to frequency error of sync block
+        self.sigmix = gr.multiply_cc()
+        self.sampler = gr.ofdm_sampler(fft_length, fft_length+cp_length)
         self.fft_demod = gr.fft_vcc(fft_length, True, win, True)
         self.ofdm_frame_acq = gr.ofdm_frame_acquisition(occupied_tones, 
fft_length,
                                                         cp_length, ks[0])
 
-        self.connect(self, self.chan_filt)
-        self.connect(self.chan_filt, self.ofdm_sync)
-        self.connect((self.ofdm_sync,0), self.fft_demod, 
(self.ofdm_frame_acq,0))
-        self.connect((self.ofdm_sync,1), (self.ofdm_frame_acq,1))
-        self.connect((self.ofdm_frame_acq,0), (self,0))
-        self.connect((self.ofdm_frame_acq,1), (self,1))
+        self.connect(self, self.chan_filt)                            # filter 
the input channel
+        self.connect(self.chan_filt, self.ofdm_sync)                  # into 
the synchronization alg.
+        self.connect((self.ofdm_sync,0), self.nco, (self.sigmix,1))   # use 
sync freq. offset output to derotate input signal
+        self.connect(self.chan_filt, (self.sigmix,0))                 # signal 
to be derotated
+        self.connect(self.sigmix, (self.sampler,0))                   # sample 
off timing signal detected in sync alg
+        self.connect((self.ofdm_sync,1), (self.sampler,1))            # timing 
signal to sample at
 
+        self.connect((self.sampler,0), self.fft_demod)                # send 
derotated sampled signal to FFT
+        self.connect(self.fft_demod, (self.ofdm_frame_acq,0))         # find 
frame start and equalize signal
+        self.connect((self.sampler,1), (self.ofdm_frame_acq,1))       # send 
timing signal to signal frame start
+        self.connect((self.ofdm_frame_acq,0), (self,0))               # 
finished with fine/coarse freq correction,
+        self.connect((self.ofdm_frame_acq,1), (self,1))               # frame 
and symbol timing, and equalization
+
         if logging:
-            self.connect(self.chan_filt, gr.file_sink(gr.sizeof_gr_complex, 
"chan_filt_c.dat"))
-            self.connect(self.fft_demod, 
gr.file_sink(gr.sizeof_gr_complex*fft_length, "fft_out_c.dat"))
+            self.connect(self.chan_filt, gr.file_sink(gr.sizeof_gr_complex, 
"ofdm_receiver-chan_filt_c.dat"))
+            self.connect(self.fft_demod, 
gr.file_sink(gr.sizeof_gr_complex*fft_length, "ofdm_receiver-fft_out_c.dat"))
             self.connect(self.ofdm_frame_acq,
-                         gr.file_sink(gr.sizeof_gr_complex*occupied_tones, 
"ofdm_frame_acq_c.dat"))
-            self.connect((self.ofdm_frame_acq,1), gr.file_sink(1, 
"found_corr_b.dat"))
+                         gr.file_sink(gr.sizeof_gr_complex*occupied_tones, 
"ofdm_receiver-frame_acq_c.dat"))
+            self.connect((self.ofdm_frame_acq,1), gr.file_sink(1, 
"ofdm_receiver-found_corr_b.dat"))
+            self.connect(self.sampler, 
gr.file_sink(gr.sizeof_gr_complex*fft_length, "ofdm_receiver-sampler_c.dat"))
+            self.connect(self.sigmix, gr.file_sink(gr.sizeof_gr_complex, 
"ofdm_receiver-sigmix_c.dat"))
+            self.connect(self.nco, gr.file_sink(gr.sizeof_gr_complex, 
"ofdm_receiver-nco_c.dat"))

Modified: 
gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_sync_pn.py
===================================================================
--- gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_sync_pn.py  
2008-04-15 05:05:46 UTC (rev 8197)
+++ gnuradio/trunk/gnuradio-core/src/python/gnuradio/blks2impl/ofdm_sync_pn.py  
2008-04-15 17:06:46 UTC (rev 8198)
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright 2007 Free Software Foundation, Inc.
+# Copyright 2007,2008 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -35,16 +35,10 @@
         
        gr.hier_block2.__init__(self, "ofdm_sync_pn",
                                gr.io_signature(1, 1, gr.sizeof_gr_complex), # 
Input signature
-                               gr.io_signature2(2, 2, 
gr.sizeof_gr_complex*fft_length, gr.sizeof_char*fft_length)) # Output signature
+                                gr.io_signature2(2, 2, gr.sizeof_float, 
gr.sizeof_char)) # Output signature
 
-        # FIXME: when converting to hier_block2's, the output signature
-        # should be the output of the divider (the normalized peaks) and
-        # the angle value out of the sample and hold block
-            
         self.input = gr.add_const_cc(0)
 
-        symbol_length = fft_length + cp_length
-
         # PN Sync
 
         # Create a delay line
@@ -80,20 +74,14 @@
 
         self.sample_and_hold = gr.sample_and_hold_ff()
 
-        # Mix the signal with an NCO controlled by the sync loop
-        nco_sensitivity = -2.0/fft_length
-        self.nco = gr.frequency_modulator_fc(nco_sensitivity)
-        self.sigmix = gr.multiply_cc()
-
         #ML measurements input to sampler block and detect
         self.sub1 = gr.add_const_ff(-1)
         self.pk_detect = gr.peak_detector_fb(0.20, 0.20, 30, 0.001)
         #self.pk_detect = gr.peak_detector2_fb(9)
 
-        self.sampler = gr.ofdm_sampler(fft_length,symbol_length)
-
         self.connect(self, self.input)
         
+        # Calculate the frequency offset from the correlation of the preamble
         self.connect(self.input, self.delay)
         self.connect(self.input, (self.corr,0))
         self.connect(self.delay, self.conjg)
@@ -102,12 +90,8 @@
         self.connect(self.moving_sum_filter, self.c2mag)
         self.connect(self.moving_sum_filter, self.angle)
         self.connect(self.angle, (self.sample_and_hold,0))
-        self.connect(self.sample_and_hold, self.nco)
 
-        self.connect(self.input, (self.sigmix,0))
-        self.connect(self.nco, (self.sigmix,1))
-        self.connect(self.sigmix, (self.sampler,0))
-
+        # Get the power of the input signal to normalize the output of the 
correlation
         self.connect(self.input, self.inputmag2, self.inputmovingsum)
         self.connect(self.inputmovingsum, (self.square,0))
         self.connect(self.inputmovingsum, (self.square,1))
@@ -121,21 +105,19 @@
         
         self.connect(self.matched_filter, self.sub1, self.pk_detect)
         #self.connect(self.matched_filter, self.pk_detect)
-        self.connect(self.pk_detect, (self.sampler,1))
         self.connect(self.pk_detect, (self.sample_and_hold,1))
 
-        # Set output from sampler
-        self.connect((self.sampler,0), (self,0))
-        self.connect((self.sampler,1), (self,1))
+        # Set output signals
+        #    Output 0: fine frequency correction value
+        #    Output 1: timing signal
+        self.connect(self.sample_and_hold, (self,0))
+        self.connect(self.pk_detect, (self,1))
 
         if logging:
             self.connect(self.matched_filter, gr.file_sink(gr.sizeof_float, 
"ofdm_sync_pn-mf_f.dat"))
             self.connect(self.normalize, gr.file_sink(gr.sizeof_float, 
"ofdm_sync_pn-theta_f.dat"))
             self.connect(self.angle, gr.file_sink(gr.sizeof_float, 
"ofdm_sync_pn-epsilon_f.dat"))
             self.connect(self.pk_detect, gr.file_sink(gr.sizeof_char, 
"ofdm_sync_pn-peaks_b.dat"))
-            self.connect(self.sigmix, gr.file_sink(gr.sizeof_gr_complex, 
"ofdm_sync_pn-sigmix_c.dat"))
-            self.connect(self.sampler, 
gr.file_sink(gr.sizeof_gr_complex*fft_length, "ofdm_sync_pn-sampler_c.dat"))
             self.connect(self.sample_and_hold, gr.file_sink(gr.sizeof_float, 
"ofdm_sync_pn-sample_and_hold_f.dat"))
-            self.connect(self.nco, gr.file_sink(gr.sizeof_gr_complex, 
"ofdm_sync_pn-nco_c.dat"))
             self.connect(self.input, gr.file_sink(gr.sizeof_gr_complex, 
"ofdm_sync_pn-input_c.dat"))