GUI: Add part of calibration routine

2 files changed, 43 insertions, 22 deletions

diff --git a/gui/dpd/Capture.py b/gui/dpd/Capture.py
index e2ac63d..4c0e99c 100644
--- a/gui/dpd/Capture.py
+++ b/gui/dpd/Capture.py
@@ -36,6 +36,9 @@ import io
 
 from . import Align as sa
 
+def correlation_coefficient(sig_tx, sig_rx):
+    return np.corrcoef(sig_tx, sig_rx)[0, 1]
+
 def align_samples(sig_tx, sig_rx):
     """
     Returns an aligned version of sig_tx and sig_rx by cropping, subsample alignment and
@@ -61,7 +64,7 @@ def align_samples(sig_tx, sig_rx):
     # Fine subsample alignment and phase offset
     sig_rx = sa.subsample_align(sig_rx, sig_tx)
     sig_rx = sa.phase_align(sig_rx, sig_tx)
-    return sig_tx, sig_rx
+    return sig_tx, sig_rx, abs(off_meas)
 
 class Capture:
     """Capture samples from ODR-DabMod"""
@@ -76,14 +79,16 @@ class Capture:
         # samples to avoid that the polynomial gets overfitted in the low-amplitude
         # part, which is less interesting than the high-amplitude part, where
         # non-linearities become apparent.
-        self.binning_start = 0.0
-        self.binning_end = 1.0
         self.binning_n_bins = 64  # Number of bins between binning_start and binning_end
         self.binning_n_per_bin = 128  # Number of measurements pre bin
 
-        self.target_median = 0.05
-        self.median_max = self.target_median * 1.4
-        self.median_min = self.target_median / 1.4
+        self.rx_normalisation = 1.0
+
+        self.clear_accumulated()
+
+    def clear_accumulated(self):
+        self.binning_start = 0.0
+        self.binning_end = 1.0
 
         # axis 0: bins
         # axis 1: 0=tx, 1=rx
@@ -156,30 +161,32 @@ class Capture:
 
         return txframe, tx_ts, rxframe, rx_ts
 
-    def get_samples(self):
-        """Connect to ODR-DabMod, retrieve TX and RX samples, load
-        into numpy arrays, and return a tuple
-        (txframe_aligned, tx_ts, tx_median, rxframe_aligned, rx_ts, rx_median)
-        """
-
+    def calibrate(self):
         txframe, tx_ts, rxframe, rx_ts = self.receive_tcp()
 
         # Normalize received signal with sent signal
         tx_median = np.median(np.abs(txframe))
+        rx_median = np.median(np.abs(rxframe))
+        self.rx_normalisation = tx_median / rx_median
 
-        if self.median_max < tx_median:
-            raise ValueError("TX median {} too high, decrease digital_gain!".format(tx_median))
-        elif tx_median < self.median_min:
-            raise ValueError("TX median {} too low, increase digital_gain!".format(tx_median))
-        else:
-            rx_median = np.median(np.abs(rxframe))
-            rxframe = rxframe / rx_median * tx_median
+        rxframe = rxframe * self.rx_normalisation
+        txframe_aligned, rxframe_aligned, coarse_offset = align_samples(txframe, rxframe)
 
-            txframe_aligned, rxframe_aligned = align_samples(txframe, rxframe)
+        return tx_ts, tx_median, rx_ts, rx_median, coarse_offset, correlation_coefficient(txframe_aligned, rxframe_aligned)
+
+    def get_samples(self):
+        """Connect to ODR-DabMod, retrieve TX and RX samples, load
+        into numpy arrays, and return a tuple
+        (txframe_aligned, tx_ts, tx_median, rxframe_aligned, rx_ts, rx_median)
+        """
 
-            self._bin_and_accumulate(txframe_aligned, rxframe_aligned)
+        txframe, tx_ts, rxframe, rx_ts = self.receive_tcp()
 
-            return txframe_aligned, tx_ts, tx_median, rxframe_aligned, rx_ts, rx_median
+        # Normalize received signal with calibrated normalisation
+        rxframe = rxframe * self.rx_normalisation
+        txframe_aligned, rxframe_aligned, coarse_offset = align_samples(txframe, rxframe)
+        self._bin_and_accumulate(txframe_aligned, rxframe_aligned)
+        return txframe_aligned, tx_ts, tx_median, rxframe_aligned, rx_ts, rx_median
 
     def bin_histogram(self):
         return [b.shape[0] for b in self.accumulated_bins]
diff --git a/gui/dpd/__init__.py b/gui/dpd/__init__.py
index 06d180d..716b8c2 100644
--- a/gui/dpd/__init__.py
+++ b/gui/dpd/__init__.py
@@ -23,6 +23,7 @@
 #   along with ODR-DabMod.  If not, see <http://www.gnu.org/licenses/>.
 
 from . import Capture
+import numpy as np
 
 class DPD:
     def __init__(self, samplerate=8192000):
@@ -50,6 +51,19 @@ class DPD:
     def pointcloud_png(self):
         return self.capture.pointcloud_png()
 
+    def clear_accumulated(self):
+        return self.capture.clear_accumulated()
+
+    def capture_calibration(self):
+        tx_ts, tx_median, rx_ts, rx_median, coarse_offset, correlation_coefficient = self.capture.calibrate()
+        result = {'status': "ok"}
+        result['length'] = len(txframe_aligned)
+        result['tx_median'] = "{:.2}dB".format(20*np.log10(tx_median))
+        result['rx_median'] = "{:.2}dB".format(20*np.log10(rx_median))
+        result['tx_ts'] = tx_ts
+        result['rx_ts'] = rx_ts
+        result['correlation'] = correlation_coefficient
+
     def capture_samples(self):
         """Captures samples and store them in the accumulated samples,
         returns a dict with some info"""