Add dpd example script to fetch samples

3 files changed, 214 insertions, 103 deletions

diff --git a/dpd/README.md b/dpd/README.md
new file mode 100644
index 0000000..828a483
--- /dev/null
+++ b/dpd/README.md
@@ -0,0 +1,10 @@
+Digital Predistortion for ODR-DabMod
+====================================
+
+This folder contains work in progress for digital predistortion. It requires:
+
+- USRP B200.
+- Power amplifier.
+- A feedback connection from the power amplifier output, at an appropriate power level for the B200.
+  Usually this is done with a directional coupler.
+- ODR-DabMod with enabled dpd_port, and with a samplerate of 8192000 samples per second.
diff --git a/dpd/show_spectrum.py b/dpd/show_spectrum.py
new file mode 100755
index 0000000..6c489e0
--- /dev/null
+++ b/dpd/show_spectrum.py
@@ -0,0 +1,99 @@
+#!/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.
+#
+# Copyright (C) 2017 Matthias P. Braendli
+# 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 as mp
+import scipy.signal
+
+SIZEOF_SAMPLE = 8 # complex floats
+
+if len(sys.argv) != 3:
+    print("Usage: show_spectrum.py <port> <number of samples to request>")
+    sys.exit(1)
+
+port = int(sys.argv[1])
+num_samps_to_request = int(sys.argv[2])
+
+
+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", s.recv(12))
+    tx_ts = tx_second + tx_pps / 16384000.0
+
+    print("Receiving {} TX samples".format(num_samps))
+    txframe_bytes = s.recv(num_samps * SIZEOF_SAMPLE)
+    txframe = np.fromstring(txframe_bytes, dtype=np.complex64)
+
+    print("Wait for RX metadata")
+    rx_second, rx_pps = struct.unpack("=II", s.recv(8))
+    rx_ts = rx_second + rx_pps / 16384000.0
+
+    print("Receiving {} RX samples".format(num_samps))
+    rxframe_bytes = s.recv(num_samps * SIZEOF_SAMPLE)
+    rxframe = np.fromstring(rxframe_bytes, dtype=np.complex64)
+
+    print("Disconnecting")
+    s.close()
+
+    return (tx_ts, txframe, rx_ts, rxframe)
+
+
+tx_ts, txframe, rx_ts, rxframe = get_samples(port, num_samps_to_request)
+
+print("Received {} & {} frames at {} and {}".format(
+    len(txframe), len(rxframe), tx_ts, rx_ts))
+
+
+# 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.
diff --git a/src/OutputUHDFeedback.cpp b/src/OutputUHDFeedback.cpp
index 8584839..09b73ba 100644
--- a/src/OutputUHDFeedback.cpp
+++ b/src/OutputUHDFeedback.cpp
@@ -38,8 +38,10 @@ DESCRIPTION:
 
 #include <vector>
 #include <complex>
+#include <cstring>
 #include <uhd/types/stream_cmd.hpp>
 #include <sys/socket.h>
+#include <errno.h>
 #include <poll.h>
 #include "OutputUHDFeedback.h"
 #include "Utils.h"
@@ -214,113 +216,113 @@ void OutputUHDFeedback::ServeFeedbackThread()
                 continue;
             }
 
-            while (m_running) {
-                uint8_t request_version = 0;
-                ssize_t read = recv(client_sock, &request_version, 1, 0);
-                if (!read) break; // done reading
-                if (read < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client read request version failed";
-                }
-
-                if (request_version != 1) {
-                    etiLog.level(info) << "DPD Feedback Server wrong request version";
-                    break;
-                }
-
-                uint32_t num_samples = 0;
-                read = recv(client_sock, &num_samples, 4, 0);
-                if (!read) break; // done reading
-                if (read < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client read num samples failed";
-                }
-
-                // We are ready to issue the request now
-                {
-                    boost::mutex::scoped_lock lock(burstRequest.mutex);
-                    burstRequest.num_samples = num_samples;
-                    burstRequest.state = BurstRequestState::SaveTransmitFrame;
-
-                    lock.unlock();
-                }
-
-                // Wait for the result to be ready
+            uint8_t request_version = 0;
+            ssize_t read = recv(client_sock, &request_version, 1, 0);
+            if (!read) break; // done reading
+            if (read < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client read request version failed: " << strerror(errno);
+                break;
+            }
+
+            if (request_version != 1) {
+                etiLog.level(info) << "DPD Feedback Server wrong request version";
+                break;
+            }
+
+            uint32_t num_samples = 0;
+            read = recv(client_sock, &num_samples, 4, 0);
+            if (!read) break; // done reading
+            if (read < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client read num samples failed";
+                break;
+            }
+
+            // We are ready to issue the request now
+            {
                 boost::mutex::scoped_lock lock(burstRequest.mutex);
-                while (burstRequest.state != BurstRequestState::Acquired) {
-                    if (not m_running) break;
-                    burstRequest.mutex_notification.wait(lock);
-                }
+                burstRequest.num_samples = num_samples;
+                burstRequest.state = BurstRequestState::SaveTransmitFrame;
 
-                burstRequest.state = BurstRequestState::None;
                 lock.unlock();
+            }
+
+            // Wait for the result to be ready
+            boost::mutex::scoped_lock lock(burstRequest.mutex);
+            while (burstRequest.state != BurstRequestState::Acquired) {
+                if (not m_running) break;
+                burstRequest.mutex_notification.wait(lock);
+            }
+
+            burstRequest.state = BurstRequestState::None;
+            lock.unlock();
+
+            if (send(client_sock,
+                        &burstRequest.num_samples,
+                        sizeof(burstRequest.num_samples),
+                        0) < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client send num_samples failed";
+                break;
+            }
+
+            if (send(client_sock,
+                        &burstRequest.tx_second,
+                        sizeof(burstRequest.tx_second),
+                        0) < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client send tx_second failed";
+                break;
+            }
+
+            if (send(client_sock,
+                        &burstRequest.tx_pps,
+                        sizeof(burstRequest.tx_pps),
+                        0) < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client send tx_pps failed";
+                break;
+            }
+
+            const size_t frame_bytes = burstRequest.num_samples * sizeof(complexf);
+
+            assert(burstRequest.tx_samples.size() == frame_bytes);
+            if (send(client_sock,
+                        &burstRequest.tx_samples[0],
+                        frame_bytes,
+                        0) < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client send tx_frame failed";
+                break;
+            }
+
+            if (send(client_sock,
+                        &burstRequest.rx_second,
+                        sizeof(burstRequest.rx_second),
+                        0) < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client send rx_second failed";
+                break;
+            }
+
+            if (send(client_sock,
+                        &burstRequest.rx_pps,
+                        sizeof(burstRequest.rx_pps),
+                        0) < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client send rx_pps failed";
+                break;
+            }
 
-                if (send(client_sock,
-                            &burstRequest.num_samples,
-                            sizeof(burstRequest.num_samples),
-                            0) < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client send num_samples failed";
-                    break;
-                }
-
-                if (send(client_sock,
-                            &burstRequest.tx_second,
-                            sizeof(burstRequest.tx_second),
-                            0) < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client send tx_second failed";
-                    break;
-                }
-
-                if (send(client_sock,
-                            &burstRequest.tx_pps,
-                            sizeof(burstRequest.tx_pps),
-                            0) < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client send tx_pps failed";
-                    break;
-                }
-
-                const size_t frame_bytes = burstRequest.num_samples * sizeof(complexf);
-
-                assert(burstRequest.tx_samples.size() == frame_bytes);
-                if (send(client_sock,
-                            &burstRequest.tx_samples[0],
-                            frame_bytes,
-                            0) < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client send tx_frame failed";
-                    break;
-                }
-
-                if (send(client_sock,
-                            &burstRequest.rx_second,
-                            sizeof(burstRequest.rx_second),
-                            0) < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client send rx_second failed";
-                    break;
-                }
-
-                if (send(client_sock,
-                            &burstRequest.rx_pps,
-                            sizeof(burstRequest.rx_pps),
-                            0) < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client send rx_pps failed";
-                    break;
-                }
-
-                assert(burstRequest.rx_samples.size() == frame_bytes);
-                if (send(client_sock,
-                            &burstRequest.rx_samples[0],
-                            frame_bytes,
-                            0) < 0) {
-                    etiLog.level(info) <<
-                        "DPD Feedback Server Client send rx_frame failed";
-                    break;
-                }
+            assert(burstRequest.rx_samples.size() == frame_bytes);
+            if (send(client_sock,
+                        &burstRequest.rx_samples[0],
+                        frame_bytes,
+                        0) < 0) {
+                etiLog.level(info) <<
+                    "DPD Feedback Server Client send rx_frame failed";
+                break;
             }
 
             close(client_sock);