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authorMatthias P. Braendli <matthias.braendli@mpb.li>2018-12-04 10:18:33 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2018-12-04 10:18:33 +0100
commitd5cbe10c0e2298b0e40161607a3da158249bdb82 (patch)
tree5f6a0ff40ce5b3dd39d0df1c348557b183b48a7e /dpd/show_spectrum.py
parent594cb2691debaa7562fd7d76d3b224701ec087ea (diff)
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Move python stuff to folder
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-#!/usr/bin/env python
-# -*- coding: utf-8 -*-
-#
-# This is an example tool that shows how to connect to ODR-DabMod's dpd TCP
-# server and get samples from there.
-#
-# Since the TX and RX samples are not perfectly aligned, the tool has to align
-# them properly, which is done in two steps: First on sample-level using a
-# correlation, then with subsample accuracy using a FFT approach.
-#
-# It requires SciPy and matplotlib.
-#
-# http://www.opendigitalradio.org
-# Licence: The MIT License, see notice at the end of this file
-
-import sys
-import socket
-import struct
-import numpy as np
-import matplotlib.pyplot as pp
-from matplotlib.animation import FuncAnimation
-import argparse
-from scipy.misc import imsave
-
-SIZEOF_SAMPLE = 8 # complex floats
-
-# Constants for TM 1
-NbSymbols = 76
-NbCarriers = 1536
-Spacing = 2048
-NullSize = 2656
-SymSize = 2552
-FicSizeOut = 288
-
-def main():
- parser = argparse.ArgumentParser(description="Plot the spectrum of ODR-DabMod's DPD feedback")
- parser.add_argument('--samps', default='10240', help='Number of samples to request at once',
- required=False)
- parser.add_argument('--port', default='50055',
- help='port to connect to ODR-DabMod DPD (default: 50055)',
- required=False)
- parser.add_argument('--animated', action='store_true', help='Enable real-time animation')
- parser.add_argument('--constellation', action='store_true', help='Draw constellaton plot')
- parser.add_argument('--samplerate', default='8192000', help='Sample rate',
- required=False)
-
- cli_args = parser.parse_args()
-
- if cli_args.constellation:
- plot_constellation_once(cli_args)
- elif cli_args.animated:
- plot_spectrum_animated(cli_args)
- else:
- plot_spectrum_once(cli_args)
-
-def recv_exact(sock, num_bytes):
- bufs = []
- while num_bytes > 0:
- b = sock.recv(num_bytes)
- if len(b) == 0:
- break
- num_bytes -= len(b)
- bufs.append(b)
- return b''.join(bufs)
-
-def get_samples(port, num_samps_to_request):
- """Connect to ODR-DabMod, retrieve TX and RX samples, load
- into numpy arrays, and return a tuple
- (tx_timestamp, tx_samples, rx_timestamp, rx_samples)
- where the timestamps are doubles, and the samples are numpy
- arrays of complex floats, both having the same size
- """
-
- s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
- s.connect(('localhost', port))
-
- print("Send version");
- s.sendall(b"\x01")
-
- print("Send request for {} samples".format(num_samps_to_request))
- s.sendall(struct.pack("=I", num_samps_to_request))
-
- print("Wait for TX metadata")
- num_samps, tx_second, tx_pps = struct.unpack("=III", recv_exact(s, 12))
- tx_ts = tx_second + tx_pps / 16384000.0
-
- if num_samps > 0:
- print("Receiving {} TX samples".format(num_samps))
- txframe_bytes = recv_exact(s, num_samps * SIZEOF_SAMPLE)
- txframe = np.fromstring(txframe_bytes, dtype=np.complex64)
- else:
- txframe = np.array([], dtype=np.complex64)
-
-
- print("Wait for RX metadata")
- rx_second, rx_pps = struct.unpack("=II", recv_exact(s, 8))
- rx_ts = rx_second + rx_pps / 16384000.0
-
- if num_samps > 0:
- print("Receiving {} RX samples".format(num_samps))
- rxframe_bytes = recv_exact(s, num_samps * SIZEOF_SAMPLE)
- rxframe = np.fromstring(rxframe_bytes, dtype=np.complex64)
- else:
- rxframe = np.array([], dtype=np.complex64)
-
- print("Disconnecting")
- s.close()
-
- return (tx_ts, txframe, rx_ts, rxframe)
-
-def recv_rxtx(port, num_samps_to_request):
- tx_ts, txframe, rx_ts, rxframe = get_samples(port, num_samps_to_request)
-
- # convert to complex doubles for more dynamic range
- txframe = txframe.astype(np.complex128)
- rxframe = rxframe.astype(np.complex128)
-
- print("Received {} & {} frames at {} and {}".format(
- len(txframe), len(rxframe), tx_ts, rx_ts))
- return tx_ts, txframe, rx_ts, rxframe
-
-def get_spectrum(port, num_samps_to_request):
- tx_ts, txframe, rx_ts, rxframe = recv_rxtx(port, num_samps_to_request)
-
- print("Calculate TX and RX spectrum assuming 8192000 samples per second")
- tx_spectrum = np.fft.fftshift(np.fft.fft(txframe, fft_size))
- tx_power = 20*np.log10(np.abs(tx_spectrum))
-
- rx_spectrum = np.fft.fftshift(np.fft.fft(rxframe, fft_size))
- rx_power = 20*np.log10(np.abs(rx_spectrum))
- return tx_power, rx_power
-
-def remove_guard_intervals(frame, options):
- """Remove the cyclic prefix. The frame needs to be aligned to the
- end of the transmission frame. Transmission Mode 1 is assumed"""
- oversample = int(int(options.samplerate) / 2048000)
-
- # From the end, take 2048 samples, then skip 504 samples
- frame = frame[::-1]
-
- stride_len = Spacing * oversample
- stride_advance = SymSize * oversample
-
- # Truncate the frame to an integer length of strides
- newlen = len(frame) - (len(frame) % stride_advance)
- print("Truncating frame from {} to {}".format(len(frame), newlen))
- frame = frame[:newlen]
-
- # Remove the cyclic prefix
- frame = frame.reshape(-1, stride_advance)[:,:stride_len].reshape(-1)
-
- # Reverse again
- return frame[::-1]
-
-
-def plot_constellation_once(options):
- port = int(options.port)
- num_samps_to_request = int(options.samps)
-
- tx_ts, txframe, rx_ts, rxframe = recv_rxtx(port, num_samps_to_request)
-
- frame = remove_guard_intervals(txframe, options)
-
- oversample = int(int(options.samplerate) / 2048000)
-
- n = Spacing * oversample # is also number of samples per symbol
- if len(frame) % n != 0:
- raise ValueError("Frame length doesn't contain exact number of symbols")
- num_syms = int(len(frame) / n)
- print("frame {} has {} symbols".format(len(frame), num_syms))
- spectrums = np.array([np.fft.fftshift(np.fft.fft(frame[n*i:n*(i+1)], n)) for i in range(num_syms)])
-
- def normalise(x):
- """Normalise a real-valued array x to the range [0,1]"""
- y = x + np.min(x)
- return x / np.max(x)
-
- imsave("spectrums.png", np.concatenate([
- normalise(np.abs(spectrums)),
- normalise(np.angle(spectrums))]))
-
- # Only take bins that are supposed to contain energy
- # i.e. the middle 1536 bins, excluding the bin at n/2
- assert(n % 2 == 0)
- n_half = int(n/2)
- spectrums = np.concatenate(
- [spectrums[...,n_half-768:n_half],
- spectrums[...,n_half + 1:n_half + 769]], axis=1)
-
- sym_indices = (np.tile(np.arange(num_syms-1).reshape(num_syms-1,1), (1,NbCarriers)) +
- np.tile(np.linspace(-0.4, 0.4, NbCarriers), (num_syms-1, 1) ) )
- sym_indices = sym_indices.reshape(-1)
- diff_angles = np.mod(np.diff(np.angle(spectrums, deg=1), axis=0), 360)
- #sym_points = spectrums[:-1].reshape(-1)
- # Set amplitude and phase of low power points to zero, avoid cluttering diagram
- #sym_points[np.abs(sym_points) < np.mean(np.abs(sym_points)) * 0.1] = 0
-
- print("ix {} spec {} da {}".format(
- sym_indices.shape, spectrums.shape, diff_angles.shape))
-
- fig = pp.figure()
-
- fig.suptitle("Constellation")
- ax1 = fig.add_subplot(111)
- ax1.set_title("TX")
- ax1.scatter(sym_indices, diff_angles.reshape(-1), alpha=0.1)
-
- pp.show()
-
-fft_size = 4096
-
-def plot_spectrum_once(options):
- port = int(options.port)
- num_samps_to_request = int(options.samps)
- freqs = np.fft.fftshift(np.fft.fftfreq(fft_size, d=1./int(options.samplerate)))
-
- tx_power, rx_power = get_spectrum(port, num_samps_to_request)
- fig = pp.figure()
-
- fig.suptitle("TX and RX spectrum")
- ax1 = fig.add_subplot(211)
- ax1.set_title("TX")
- ax1.plot(freqs, tx_power, 'r')
- ax2 = fig.add_subplot(212)
- ax2.set_title("RX")
- ax2.plot(freqs, rx_power, 'b')
- pp.show()
-
-def plot_spectrum_animated(options):
- port = int(options.port)
- num_samps_to_request = int(options.samps)
- freqs = np.fft.fftshift(np.fft.fftfreq(fft_size, d=1./int(options.samplerate)))
-
- fig, axes = pp.subplots(2, sharex=True)
- line1, = axes[0].plot(freqs, np.ones(len(freqs)), 'r', animated=True)
- axes[0].set_title("TX")
- line2, = axes[1].plot(freqs, np.ones(len(freqs)), 'b', animated=True)
- axes[1].set_title("RX")
- lines = [line1, line2]
-
- axes[0].set_ylim(-30, 50)
- axes[1].set_ylim(-60, 40)
-
- def update(frame):
- tx_power, rx_power = get_spectrum(port, num_samps_to_request)
-
- lines[0].set_ydata(tx_power)
- lines[1].set_ydata(rx_power)
- return lines
-
- ani = FuncAnimation(fig, update, blit=True)
- pp.show()
-
-main()
-
-# The MIT License (MIT)
-#
-# Copyright (c) 2017 Matthias P. Braendli
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in all
-# copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-# SOFTWARE.