signal-processing

I have never worked with audio signals before and little do I know about signal processing. Nevertheless, I need to represent and audio signal using pyplot.specgram function from matplotlib library. Here is how I do it. import matplotlib.pyplot as plt import scipy.io.wavfile as wavfile rate, frames = wavfile.read("song.wav") plt.specgram(frames) The result I am getting is this nice spectrogram below: When I look at x-axis and y-axis which I suppose are frequency and time domains I can't get my head around the fact that frequency is scaled from 0 to 1.0 and time from 0 to 80k . What is the

I'm trying to build a video chat program using Adobe Flex but there is a giant problem with echos. If the participants arn't using headsets, everything they say echos. Worse, they can actually create positive feedback loop of echos that won't end until the mics are muted. Has anyone found a solution for this on the Flex/Flash platform? My software is using the Speex codec and I've done my best to eliminate all buffering (i.e. it's a live stream and I set the buffer length to 0). The loop back option is turned off and the "Use Echo Suppression" is turned on. I'm using the Red5 server for the

This question was migrated from Signal Processing Stack Exchange because it can be answered on Stack Overflow. Migrated 5 years ago . Learn more . scipy.signal.cwt 's documentation says : scipy.signal.cwt(data, wavelet, widths) wavelet : function Wavelet function, which should take 2 arguments. The first argument is the number of points that the returned vector will have (len(wavelet(width,length)) == length). The second is a width parameter, defining the size of the wavelet (e.g. standard deviation of a gaussian). See ricker, which satisfies these requirements.wavelet : function Wavelet

In testing a conjecture about the following recursive relation , which claims a periodicity of some kind for the sequence of numbers, I wrote a python program which computes the sequences and prints them in a table. 1 # Consider the recursive relation x_{i+1} = p-1 - (p*i-1 mod x_i) 2 # with p prime and x_0 = 1. What is the shortest period of the 3 # sequence? 4 5 from __future__ import print_function 6 import numpy as np 7 from matplotlib import pyplot as plt 8 9 # The length of the sequences. 10 seq_length = 100 11 12 upperbound_primes = 30 13 14 # Computing a list of prime numbers up to n

I'm new to signal processing (and numpy, scipy, and matlab for that matter). I'm trying to estimate vowel formants with LPC in Python by adapting this matlab code: http://www.mathworks.com/help/signal/ug/formant-estimation-with-lpc-coefficients.html Here is my code so far: #!/usr/bin/env python import sys import numpy import wave import math from scipy.signal import lfilter, hamming from scikits.talkbox import lpc """ Estimate formants using LPC. """ def get_formants(file_path): # Read from file. spf = wave.open(file_path, 'r') # http://www.linguistics.ucla.edu/people/hayes/103/Charts/VChart