Fixed overlapping due to resampling

Fixes #9
aerospaceresearch · May 21, 2018 · e2e9d6e · e2e9d6e
1 parent fed2f9b
commit e2e9d6e
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Showing 6 changed files with 330 additions and 4 deletions.
diff --git a/directdemod/chunker.py b/directdemod/chunker.py
@@ -9,6 +9,9 @@
 It is responsible for creating chunks of the signal and store the info to be used later
 It can be helpful for avoiding border issues in filters and demods
 '''
+
+# POSSIBLE TODO: automatic distinction in get/set for every cycle. will avoid need of 'uniq'
+
 class chunker:
 
     '''

diff --git a/directdemod/comm.py b/directdemod/comm.py
@@ -91,13 +91,14 @@ def filter(self, filt):
         self.updateSignal(filt.applyOn(self.signal))
         return self
 
-    def bwLim(self, tsampRate, strict = False):
+    def bwLim(self, tsampRate, strict = False, uniq = "abcd"):
 
         '''Limit the bandwidth by downsampling
 
         Args:
             tsampRate (:obj:`int`): target sample rate
             strict (:obj:`bool`, optional): if true, the target sample rate will be matched exactly
+            uniq (:obj:`str`, optional): in case chunked signal, uniq is to differentiate different bwLim funcs
 
         Returns:
             :obj:`commSignal`: Updated signal (self)
@@ -107,12 +108,23 @@ def bwLim(self, tsampRate, strict = False):
             raise ValueError("The target sampling rate must be less than current sampling rate")
 
         if strict:
+
+            # will be depreciated later on, try not to use
+
             self.__sig = signal.resample(self.signal, int(tsampRate * self.length/self.sampRate))
             self.__sampRate = tsampRate
             self.__len = len(self.signal)
+
         else:
             jumpIndex = int(self.sampRate / tsampRate)
-            self.__sig = self.signal[0::jumpIndex]
+
+            offset = 0
+            if not self.__chunker is None:
+                offset = self.__chunker.get(constants.CHUNK_BWLIM + uniq, 0)
+                nextOff = (jumpIndex - (self.length - offset)%jumpIndex)%jumpIndex
+                self.__chunker.set(constants.CHUNK_BWLIM + uniq, nextOff)
+
+            self.__sig = self.signal[offset::jumpIndex]
             self.__sampRate = int(self.sampRate/jumpIndex)
             self.__len = len(self.signal)
         return self

diff --git a/directdemod/constants.py b/directdemod/constants.py
@@ -23,4 +23,5 @@
 FLT_BS = 3
 
 ## Chunker var names
-CHUNK_FREQOFFSET = "freqoffset"
+CHUNK_FREQOFFSET = "freqoffset"
+CHUNK_BWLIM = "bwlim"
diff --git a/experiments/.ipynb_checkpoints/Experiment 6 - Resampling and chunking-checkpoint.ipynb b/experiments/.ipynb_checkpoints/Experiment 6 - Resampling and chunking-checkpoint.ipynb
@@ -0,0 +1,155 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Experiment 6 - Resampling and chunking"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "during resampling, border issues may arise due to chunking. This experiment is to study those and try to correct them"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "import os, sys\n",
+    "nb_dir = os.path.split(os.getcwd())[0]\n",
+    "if nb_dir not in sys.path:\n",
+    "    sys.path.append(nb_dir)\n",
+    "    \n",
+    "%matplotlib inline\n",
+    "%load_ext autoreload\n",
+    "%autoreload 2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "from directdemod import chunker, comm\n",
+    "import numpy as np"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Let us try to see if a problem arises. Let us try to resample a given array 'a', downsampling by factor of 4"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 0  4  8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96]\n",
+      "[  0.   4.   8.  10.  14.  18.  20.  24.  28.  30.  34.  38.  40.  44.  48.\n",
+      "  50.  54.  58.  60.  64.  68.  70.  74.  78.  80.  84.  88.  90.  94.  98.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "sigOrig = comm.commSignal(40, range(100))\n",
+    "sigOrig.bwLim(10)\n",
+    "print(sigOrig.signal)\n",
+    "\n",
+    "sigTest = comm.commSignal(40, range(100))\n",
+    "chunkerObj = chunker.chunker(sigTest, 10)\n",
+    "sigTestOut = comm.commSignal(10)\n",
+    "for i in chunkerObj.getChunks:\n",
+    "    sig = comm.commSignal(40, sigTest.signal[i[0]:i[1]]).bwLim(10)\n",
+    "    sigTestOut.extend(sig)\n",
+    "print(sigTestOut.signal)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Clearly they are not the same. In order to correct this, we use the chunker obj. Chunker obj will then store some memory that will help in correcting these border issues."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 39,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 0  4  8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96]\n",
+      "[  0.   4.   8.  12.  16.  20.  24.  28.  32.  36.  40.  44.  48.  52.  56.\n",
+      "  60.  64.  68.  72.  76.  80.  84.  88.  92.  96.]\n",
+      "[ True  True  True  True  True  True  True  True  True  True  True  True\n",
+      "  True  True  True  True  True  True  True  True  True  True  True  True\n",
+      "  True]\n"
+     ]
+    }
+   ],
+   "source": [
+    "sigOrig = comm.commSignal(40, range(100))\n",
+    "sigOrig.bwLim(10)\n",
+    "print(sigOrig.signal)\n",
+    "\n",
+    "sigTest = comm.commSignal(40, range(100))\n",
+    "chunkerObj = chunker.chunker(sigTest, 10)\n",
+    "sigTestOut = comm.commSignal(10)\n",
+    "for i in chunkerObj.getChunks:\n",
+    "    sig = comm.commSignal(40, sigTest.signal[i[0]:i[1]], chunkerObj).bwLim(10)\n",
+    "    sigTestOut.extend(sig)\n",
+    "print(sigTestOut.signal)\n",
+    "\n",
+    "print(np.array(sigOrig.signal) == np.array(sigTestOut.signal))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Conclusion\n",
+    "\n",
+    "The problem was solved, by using the chunker object to retain some memory."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.1"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
diff --git a/experiments/Experiment 6 - Resampling and chunking.ipynb b/experiments/Experiment 6 - Resampling and chunking.ipynb
@@ -0,0 +1,155 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Experiment 6 - Resampling and chunking"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "during resampling, border issues may arise due to chunking. This experiment is to study those and try to correct them"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "import os, sys\n",
+    "nb_dir = os.path.split(os.getcwd())[0]\n",
+    "if nb_dir not in sys.path:\n",
+    "    sys.path.append(nb_dir)\n",
+    "    \n",
+    "%matplotlib inline\n",
+    "%load_ext autoreload\n",
+    "%autoreload 2"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 28,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "from directdemod import chunker, comm\n",
+    "import numpy as np"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Let us try to see if a problem arises. Let us try to resample a given array 'a', downsampling by factor of 4"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 29,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 0  4  8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96]\n",
+      "[  0.   4.   8.  10.  14.  18.  20.  24.  28.  30.  34.  38.  40.  44.  48.\n",
+      "  50.  54.  58.  60.  64.  68.  70.  74.  78.  80.  84.  88.  90.  94.  98.]\n"
+     ]
+    }
+   ],
+   "source": [
+    "sigOrig = comm.commSignal(40, range(100))\n",
+    "sigOrig.bwLim(10)\n",
+    "print(sigOrig.signal)\n",
+    "\n",
+    "sigTest = comm.commSignal(40, range(100))\n",
+    "chunkerObj = chunker.chunker(sigTest, 10)\n",
+    "sigTestOut = comm.commSignal(10)\n",
+    "for i in chunkerObj.getChunks:\n",
+    "    sig = comm.commSignal(40, sigTest.signal[i[0]:i[1]]).bwLim(10)\n",
+    "    sigTestOut.extend(sig)\n",
+    "print(sigTestOut.signal)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Clearly they are not the same. In order to correct this, we use the chunker obj. Chunker obj will then store some memory that will help in correcting these border issues."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 39,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[ 0  4  8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96]\n",
+      "[  0.   4.   8.  12.  16.  20.  24.  28.  32.  36.  40.  44.  48.  52.  56.\n",
+      "  60.  64.  68.  72.  76.  80.  84.  88.  92.  96.]\n",
+      "[ True  True  True  True  True  True  True  True  True  True  True  True\n",
+      "  True  True  True  True  True  True  True  True  True  True  True  True\n",
+      "  True]\n"
+     ]
+    }
+   ],
+   "source": [
+    "sigOrig = comm.commSignal(40, range(100))\n",
+    "sigOrig.bwLim(10)\n",
+    "print(sigOrig.signal)\n",
+    "\n",
+    "sigTest = comm.commSignal(40, range(100))\n",
+    "chunkerObj = chunker.chunker(sigTest, 10)\n",
+    "sigTestOut = comm.commSignal(10)\n",
+    "for i in chunkerObj.getChunks:\n",
+    "    sig = comm.commSignal(40, sigTest.signal[i[0]:i[1]], chunkerObj).bwLim(10)\n",
+    "    sigTestOut.extend(sig)\n",
+    "print(sigTestOut.signal)\n",
+    "\n",
+    "print(np.array(sigOrig.signal) == np.array(sigTestOut.signal))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Conclusion\n",
+    "\n",
+    "The problem was solved, by using the chunker object to retain some memory."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.1"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
diff --git a/noaa_cli.py b/noaa_cli.py
@@ -23,7 +23,7 @@
 fmDemdulator = fmDemod.fmDemod()
 chunkerObj = chunker.chunker(sigsrc)
 for i in chunkerObj.getChunks[:]:
-    sig = comm.commSignal(constants.IQ_SDRSAMPRATE, sigsrc.read(*i), chunkerObj).offsetFreq(constants.IQ_FREQOFFSET).filter(bhFilter).bwLim(constants.IQ_FMBW).funcApply(fmDemdulator.demod).bwLim(constants.NOAA_AUDSAMPRATE, True)
+    sig = comm.commSignal(constants.IQ_SDRSAMPRATE, sigsrc.read(*i), chunkerObj).offsetFreq(constants.IQ_FREQOFFSET).filter(bhFilter).bwLim(constants.IQ_FMBW, uniq = "First").funcApply(fmDemdulator.demod).bwLim(constants.NOAA_AUDSAMPRATE, True)
     audioOut.extend(sig)
 
 sink.wavFile("out.wav", audioOut).write