scope now can decimate points with smoothing

1 files changed, 25 insertions, 7 deletions

diff --git a/qolab/hardware/scope/sds1104x.py b/qolab/hardware/scope/sds1104x.py
index 1b9b39e..63895f6 100644
--- a/qolab/hardware/scope/sds1104x.py
+++ b/qolab/hardware/scope/sds1104x.py
@@ -6,6 +6,7 @@ from qolab.hardware.scope import ScopeSCPI
 from qolab.hardware.scpi import response2numStr
 from qolab.data.trace import Trace, TraceXY
 import numpy as np
+import scipy.signal
 
 class SDS1104X(ScopeSCPI):
     """ Siglent SDS1104x scope """
@@ -58,14 +59,24 @@ class SDS1104X(ScopeSCPI):
             Npnts = int(np.floor(availableNpnts/sparsing))
         return(sparsing, Npnts, availableNpnts, maxRequiredPoints)
 
-    def getRawWaveform(self, chNum, availableNpnts=None, maxRequiredPoints=None):
+    def getRawWaveform(self, chNum, availableNpnts=None, maxRequiredPoints=None, decimate=True):
+        """
+        If decimate is used, we get all available points and then low-pass filter them.
+        The result is less noisy. But transfer time from the instrument is longer.
+        If decimate=False we might see aliasing, if there is a high frequency noise
+        and sparsing > 1
+        """
+
         (sparsing, Npnts, availableNpnts, maxRequiredPoints) = self.calcSparsingAndNumPoints(availableNpnts, maxRequiredPoints)
-        if sparsing == 1 and Npnts == availableNpnts:
+        if (sparsing == 1 and Npnts == availableNpnts) or decimate:
             # we are getting all of it
             cstr = f'WAVEFORM_SETUP NP,0,FP,0,SP,{sparsing}'
             # technically when we know Npnts and sparsing
             # we can use command from the follow up 'else' clause
         else:
+            # we just ask every point with 'sparsing' interval
+            # fast to grab but we could do better with more advance decimate
+            # method, which allow better precision for the price of longer acquisition time
             cstr = f'WAVEFORM_SETUP SP,{sparsing},NP,{Npnts},FP,0'
             # Note: it is not enough to provide sparsing (SP),
             # number of points (NP) needed to be calculated properly too!
@@ -91,7 +102,11 @@ class SDS1104X(ScopeSCPI):
         # expected full reply: 'C1:WF DAT2,#9000000140.........'
         trRaw = Trace(f'Ch{chNum}')
         trRaw.values = wfRaw.reshape(wfRaw.size,1)
-        trRaw.unit = 'count'
+        if decimate and sparsing != 1:
+            numtaps = 3; # not sure it is the best case
+            trRaw.values = scipy.signal.decimate(trRaw.values, sparsing, 3, axis=0)
+        trRaw.config['unit'] = 'Count'
+        trRaw.config['tags']['Decimate'] = decimate
         return(trRaw, availableNpnts, Npnts)
 
     def getChanVoltsPerDiv(self, chNum):
@@ -133,8 +148,11 @@ class SDS1104X(ScopeSCPI):
         return(float(numberString))
 
 
-    def getWaveform(self, chNum, availableNpnts=None, maxRequiredPoints=None):
-        trRaw, availableNpnts, Npnts = self.getRawWaveform(chNum, availableNpnts=availableNpnts, maxRequiredPoints=maxRequiredPoints)
+    def getWaveform(self, chNum, availableNpnts=None, maxRequiredPoints=None, decimate=True):
+        """
+        For decimate use see getRawWaveform. In short decimate=True is slower but more precise.
+        """
+        trRaw, availableNpnts, Npnts = self.getRawWaveform(chNum, availableNpnts=availableNpnts, maxRequiredPoints=maxRequiredPoints, decimate=decimate)
         VoltageOffset = self.getChanOffset(chNum)
         VoltsPerDiv = self.getChanVoltsPerDiv(chNum)
         tr = trRaw
@@ -165,8 +183,8 @@ class SDS1104X(ScopeSCPI):
         t.config['tags']['Sparsing']   = sparsing
         return(t)
         
-    def getTrace(self, chNum, availableNpnts=None, maxRequiredPoints=None):
-        wfVoltage, availableNpnts = self.getWaveform( chNum, availableNpnts=availableNpnts, maxRequiredPoints=maxRequiredPoints)
+    def getTrace(self, chNum, availableNpnts=None, maxRequiredPoints=None, decimate=True):
+        wfVoltage, availableNpnts = self.getWaveform( chNum, availableNpnts=availableNpnts, maxRequiredPoints=maxRequiredPoints, decimate=decimate)
         t = self.getTimeTrace(availableNpnts=availableNpnts, maxRequiredPoints=maxRequiredPoints)
         tr = TraceXY( f'Ch{chNum}' )
         tr.x = t