# All Questions

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### Audio frequency modulation

Wanting to build an audio circuit capable of taking sub-sonic and ultra-sonic audio input and stepping the frequency to human hearing range. Also looking for a mic that would pick up sub- and ultra- ...
8 views

### How do i detect if an image has a gradient or not?

I have coloured images, some may be just clipart, some may be artwork, both could be with or without gradients. Before i run a colour counting algorithm on them, i want to detect if the image has ...
7 views

### Isolated word classification using LDA

I would like to do a project on speech processing. How can I classify isolated word using linear discriminant analysis for my speaker recognition project.
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### Acoustic record and store devices

I am working on a project involving analysis of bird sounds and I want to record these sounds in slightly remote locations. It is enough if the device can only record and store them (maybe in an SD ...
12 views

### Deconvolution of multiple signals

I have 2 matrices in Matlab, both are 53513 x 25 array; One is a raw signal of the 25 samples. Other begin the recorded signal. I was hoping to perform deconvolution between these 2 signals across ...
21 views

### FIR Filter length Upper Bound

Say I want to design a low pass filter with stop and pass band ripple constrained to $\epsilon$ and transition region $\delta$, what is the smallest FIR Filter length that suffices? Can you please ...
24 views

### Time period to Instantaneous frequency

I have simple smooth time signal with different time period. I would like to transfer period over the time to frequency, and to track frequency changing over the time, I would call it Instantaneous ...
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### Barrier load cell digitial filtering with known pre-collision noise

I have a signal processing (filtering) problem that I would love to bounce off the community and receive some feedback. First, the context: Longitudinal barrier load cell force-time data for high ...
25 views

### Sample rate changing audio pitch

I am using rtl-sdr at an adjustable sample rate to get stuff from a WBFM radio station. I then filter and demodulate it. When I sample at 2.4Msps, the sound is 'choppy'. I tied the sample rate to a ...
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### Algorithm to compare two audio signals: source and recorded file

I have two audio signals: source .wav file, and recorded audio file (.wav). Lets assume both signals have same duration. What algorithm should I use to detect recording quality? Notice that source ...
21 views

### Beat Detection with Arduino

I'm trying to make a robot dance on several songs using Arduino. I need to understand how to get the rhythm from the songs, something like detecting the beats, calculating the bpm.. I'm not expert but ...
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### How to determine cut-off frequency using power spectral density?

I am new to DSP and my question is a very simple one. It is about determining the right cut-off frequency. I calculate the power spectral density using FFT by Welch's algorithm. However I am confused ...
25 views

### Do Causal Discrete-time systems have proper transfer functions?

In the case of continuous-time systems, if the system is causal, its Laplace transfer function is strictly proper (the degree of the numerator is less than the degree of the denominator). Is this ...
42 views

### How does 3D Time-of-Flight (TOF) camera work?

This is my first post in this forum! So Point me if anything is not clear! I want to know how TOF camera works? So I've done Google & read some nice explanation about How Phase difference between ...
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### Finding a Priori SNR using decision directed approach from Ephraim and Malah's Paper

I'm using this paper by Y. Ephraim and D. Malah and the decision directed approach mentioned in the paper. But there is this formula eq no 53 which uses recursion to find priori SNR but i am having ...
21 views

### FIR vs. IIR for filter realization [on hold]

What are the pros and cons of using FIR versus IIR structures for the realization of a digital filter ?
8 views

### SRAD code in matlab it doesn't work [on hold]

i just applied the SRAD code in matlab and i get error in line 430 ...
23 views

### How to find the output signal of a filter using state space matrices?

I have a filter. It has two poles and two zeros. I found the state space equations and the matrices A, B, C, and D Now. I have 9 samples that I need to process with my filter. How do I use A,B,C,D ...
13 views

### Calculating Savitsky-Golay filter coefficients - normalization

using the matrix equations found on Wikipedia i wrote some Python code to compute the Savitsky-Golay coefficients for m data-points, using a polynomial of degree k, here it is: ...
42 views

### Sub pixel shift causes weird results

I am trying to shift an image on a subpixel level, with the method described here: ...
39 views

### FIR filter design with frequency sampling method - setting proper phase response for IDFT

I'd like to implement freuqency sampling method for linear phase FIR filter design using IDFT transform. My procedure goes like this : determine desired magnitude response value in frequency points ...
44 views

### Phase Estimation in speech enhancement

I am reading a recent paper titled "Phase Estimation of Speech Enhancement - unimportant, important, or impossible?" by Grekmann et al. published in the 2012 the IEEE convention. The paper proposes an ...
21 views

### Choosing the frequency for a comb filter

I have an audio sample. From doing FFT on it it looks as if I need to use a comb filter to remove resonant frequencies. This is what I generate: I honestly have no clue where to start ...
38 views

### Frequency of a noisy signal with fixed width pulses

My electricity meter has a front panel LED which pulses in proportional to the current energy rate. The frequency changes but the pulse width is set at 250ms. Due to environmental conditions there's ...
23 views

### Feature extraction and Variance

I see there is a relationship between the Variance of a signal (i.e EEG signal) and features extraction of that signal. for example PCA tend to take almost of the variance of the original signal , but ...
89 views

### Why does FFT generate a jaggedy signal

I have an application that fills a buffer from my computer's microphone and does an FFT. My objective is to figure out what frequencies are in the sample. I've tested the application by whistling as ...
18 views

### Bit Error Rate of K-means [closed]

Can you help me in finding the bit error rate after applying the K-means clustering algorithm on observations. Thank you Kawther
41 views

### Converting raw I/Q to dB

I am getting I/Q data from a software-defined radio. I want to do some stuff on signals in the data, but only if it exceeds a certain range. What is the general procedure to get dB (dBm, or ...
22 views

### Adaptive Line noise removal using IIR notch filters

I'm trying to filter out line noise(60Hz and 120Hz) from a EEG signals received over a bluetooth link. I'm proposing to use a IIR notch filter to filter out the line-noise which varies w.r.t to ...
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### Effects of DC offset on a signal

What are some of the reasons why DC offset is considered undesirable for a timeseries signal other than wastage of power during transmission ? Specifically, How does it cause spectral leakage and out ...
38 views

### convolution matrix for image scaling

Is there any way how to compute convolution matrix for Nearest Neighbor (bicubic, bilinear) image scaling (upscale/downscale)?
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### work on paper useing matlab dsp

I'm going on a research paper on the cardiac signal processing methods, the implementation and practice. Downloads In: http://s5.picofile.com/file/8153336292/DSP_Project_1393_1_.pdf.html In this ...
34 views

### The Nyquist-Theorm behind the fft

I saw a code in Python in the scipy.org (http://docs.scipy.org/doc/scipy-dev/reference/tutorial/fftpack.html) and found this: First question: Is it right that T = 1/800 <==> fs = 800 Hz fulfill ...
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### SURF SIFT detection

Do you have any idea if the surf extracted or detected interest points belongs to the same objects? I explain: SURF descriptor account the orientation of ip based on edges intensities around it. In ...
42 views

### Need help to understanding concept of particle filter

I get confuse with the basic theory of particle filter for tracking single object.. What I want to ask is: In some paper, they explained about velocity in state vector.. Are we randomly put number ...
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### Quadrature subsampling result not as expected

Let's suppose I have an ADC running at 81.824MHz. I am quadrature subsampling a signal that is at 143.5MHz using a sampling rate of 81.824MHz/4 = 20.456MHz = Fs. I expect the signal to appear at ...