1#!/usr/bin/python 2 3# ---------------------------------------------------------------------------- 4# 5# Copyright (C) 2008-2020 Fons Adriaensen <fons@linuxaudio.org> 6# 7# This program is free software; you can redistribute it and/or modify 8# it under the terms of the GNU General Public License as published by 9# the Free Software Foundation; either version 3 of the License, or 10# (at your option) any later version. 11# 12# This program is distributed in the hope that it will be useful, 13# but WITHOUT ANY WARRANTY; without even the implied warranty of 14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15# GNU General Public License for more details. 16# 17# You should have received a copy of the GNU General Public License 18# along with this program. If not, see <http:#www.gnu.org/licenses/>. 19# 20# ---------------------------------------------------------------------------- 21 22 23import numpy as np 24import matplotlib.pyplot as plt 25from math import * 26from time import sleep 27from jacktools.jacksignal import JackSignal 28 29 30# ------- Frequency response measurement using impulse and FFT --------- 31# 32# Make sure jnoisemeter is running, using 33# input 1, and select the A, C or ITU filter. 34 35# Create a JackSignal object and connect. 36# 37J = JackSignal("JackSignal") 38if J.get_state() < 0: 39 print ("Failed to create JackSignal -- is Jack running ?") 40 exit(1) 41J.create_output (0, "out-1") 42J.create_input (0, "in-1") 43 44J.silence() 45J.connect_output (0, "jnoisemeter:in_1") 46J.connect_input (0, "jnoisemeter:out") 47 48 49# Get Jack info. 50# 51name, fsamp, period = J.get_jack_info () 52 53# Parameters 54# 55impval = 1.0 56fftlen = 64 * 1024 57 58# Generate data. 59# 60Aout = np.zeros ([100,], dtype = np.float32) 61Aout [0] = impval 62 63Ain1 = np.empty ([fftlen,], dtype = np.float32) 64Freq = np.linspace (0, fsamp / 2, num = fftlen // 2 + 1) 65 66J.set_output_data (0, Aout) 67J.set_input_data (0, Ain1, nskip = period) # Skip one period. 68 69# Run the test 70# 71J.process() 72J.wait () 73del J 74 75# Process the result 76# 77Spec = np.fft.rfft (Ain1) 78 79# Display impulse and magnitude response. 80# 81fig = plt.figure (figsize=(8,6), facecolor='white') 82ax1 = fig.add_axes ([0.07, 0.04, 0.90, 0.44]) 83ax1.set_ylim (-1.5, 1.5) 84ax1.plot (Ain1 [0:100], color='b', lw=1) 85ax1.grid () 86ax2 = fig.add_axes ([0.07, 0.53, 0.90, 0.44]) 87ax2.set_xlim (20, 20e3) 88ax2.set_ylim (-60, 15) 89ax2.set_xscale ('log') 90ax2.plot (Freq, 20 * np.log10 (np.abs (Spec) + 1e-10), color='b', lw=1) 91ax2.grid () 92plt.show() 93