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Questions tagged [signal-analysis]

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0
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1answer
18 views

How to find spectral density of a signal whose correlation depends on time?

Suppose we have two uncorrelated, real white noise $\xi_1(t)$ and $\xi_2(t)$, with zero mean, and equal variance. Now, I create the signal $\xi(t) = a\xi_1(t)\cos(\omega_0 t) + b\xi_2(t) \sin(\...
0
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2answers
23 views

I am trying to convert a signal into another unit, but the error keeps increasing during each iteration

I have a signal, A, and I want to convert it into another unit by using a formula: $$s_i = \frac{(1+x_i)}{(1-x_i)}\cdot s_{i-1}$$ where $x_i$ is each sample of ...
1
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1answer
54 views

What kind of power spectrum implies uncorrelation in time?

I am new in signal processing field, and actually I just need some basic tools for what I am working on. I've learnt that the autocorrelation function is the inverse Fourier transform of the signal's ...
2
votes
2answers
1k views

Order analysis or order tracking

Last week I've been trying to implement the Order Analysis in MATLAB in vain. I've read a lot of docs about it like this one , but I still can't figure it out. This will be my last shot. Say I have ...
0
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2answers
44 views

Decoding .wav file to bit level data

I have been given the following waveform and asked to read the data and write to a buffer using Java. The .wav file has a sampling rate of 44100 Hz, 2 channel and 16-bit depth. From the waveform, I ...
7
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1answer
1k views

Why sampling a periodic signal doesn't yield a periodic discrete signal?

I've been studying Signals and systems lately and I've came across a bullet point in a slide that claims "The uniform sampling of a periodic continuous-time signal may not be periodic!". Can someone ...
3
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2answers
1k views

Digital filters in LabVIEW

I am very new in signal processing and using digital filters. I have to use a low-pass filter to analyze my data in LabVIEW and have a question about it. Any help and advice is appreciated. I am ...
0
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1answer
16 views

Log Distance-Normal Shadow Model and Friis

Since I'm founding several but different results about this model, I would ask you if all it is OK with this formulas: 1) Friis Model --> $Pr_0 = Pt + Gt + Gr + 20\log_{10}\frac{\lambda}{4\pi d}$ 2) ...
-1
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1answer
40 views

What does this spectrogram mean?This is spectrogram of a multitone FM signal

! The spectrogram of FM signal has been generated by using Matlab.Now I want to what does these scratch like lined represent, though I have only two frequency components in my message signal(https://i....
3
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1answer
30 views

How to match two signals that have similar shape but are scaled and expanded?

I have two signals A and B in time domain as follows: Visually both signals look very similar; however the X and Y axis range are different for both the signals. Signal B is basically a "stretched" ...
0
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1answer
35 views

How to detect if a signal raises sharply or slowly?

so how can i detect if a signal raises sharply or not ? Are there easy solutions (i suppose there are) ? the problem is that if a signal raises sharply, i need less data to not pollute the dataset ...
0
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0answers
13 views

Derivation of the reassigned STFT magnitude of a complex exponential

I have a complex exponential defined as $x(t)=Ae^{i2\pi f_{0}t}$ and its short time Fourier transform with respect to the analysis window, $g(t)$ is defined as, $$X_{g}(b,f) = \int_\mathbb{R} x(t+b)g(...
0
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0answers
24 views

How to generate wireless O-QPSK modulated signal in Matlab?

I am trying to create a small simulation where I would need to transmit a wireless signal from one wireless node to another and then transmit one more message back to node 1. Considering this is LR-...
0
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0answers
24 views

How to compare two 802.15.4 O-QPSK modulated digitals signals?

I am working on wireless sensors project and I am trying to simulate a transmission between two nodes. So let's say I have two nodes which transmit the message to each other, i.e. node 1 transmits ...
0
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1answer
19 views

Understanding Baud Rate

I am new to signal processing and just trying to understand what Baud rate really means. As I understand it, the baud rate speed is really the time that the processor takes when it is ON and when it ...
0
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0answers
30 views

High quality removing gravity from accelerometer data without Sensor Fusion

My smartphone have only accelerometer sensor. I need to get data close to (0,0,0) in hold in my own application. I did use some app from Google Play and data was very close to it (some like 0.1 and ...
0
votes
1answer
24 views

What are some of the disadvantages of parametric PSD estimation methods?

Roughly speaking, the methods of power-spectra estimation can be divided in two categories : parametric and non-parametric. From what I understood, parametric methods assumes that the signal can be ...
0
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2answers
96 views

Alamouti Scheme. MISO. STBC for real constellation

I have a real orthogonal design for codeword... $$ \begin{bmatrix} s1 & s2 \\ -s2 & s1 \end{bmatrix} $$ $$ s=\begin{bmatrix} s1\\ s2 \end{bmatrix} $$ $$ Y^T=\sqrt{\frac{P}{Mt}} h^T ...
0
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2answers
173 views

Accelerometer BMI160 changing bias

Goal: Obtain the 3-axis accelerations from the Bosch BMI160 IMU when measuring the accelerations of the bogie of a commercial train. The accelerometer used is installed in a PCB and used by an mbed ...
1
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0answers
35 views

How to find the period of a given signal? [duplicate]

I'm new to Signal Analysis. I have a manually generated Signal from a Gyroscope, which looks like in the picture below and I need to extract the X-Values for each period. Is there some technique to ...
0
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2answers
73 views

What is meant by finite action signal

In section 1.3 from Signals, Systems and Inference, Alan V. Oppenheim, George C. Verghese. Finite-action signals, which are also called absolutely summable signals, are defined by the condition \begin{...
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0answers
49 views

Which equipment to use for testing performance of AM, FM, and DAB

I want to test the performance of AM, FM and DAB radio in RTL-SDR. I want to measure sensitivity, adjacent channel selectivity, cross-modulation/blocking, and third-order intermodulation to be some of ...
0
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2answers
384 views

Quantify the difference between two audio spectrograms

I have two speech signals of the same length. They contain the exact same speech content but are recorded from two different microphones. I want to compare the differences between them. 1) Assuming ...
1
vote
3answers
110 views

Resample audio signal with a low factors

Currently, we need to handle a piece of an audio signal. We want to resample it with different factor rate (p/q) starting with 1.0002 to 0.9998 with a decrement of 0.000005. But Matlab function cannot ...
0
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1answer
19 views

Higher side lobe levels in linear array beam pattern

I am working on beam forming of high frequency (>400 KHz) linear array for imaging sonar. I have gathered sensor data of 80 channel linear array sub merged halfway in 8 m deep water tank with a ...
0
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0answers
24 views

barker sequence in signal processing

In our class test we were given a signal with barker sequence and a 10101010... sequence ahead of that and were asked it's importance. So what is the significance of that 10101... sequence?
0
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1answer
36 views

Please help me understand this paper about Discrete Wavelet Transform!

I am trying to understand this paper says. I have found this paragraph to be vague: (a) Preprocessing Stage. The first step in this stage was to apply the Discrete Wavelet Transform (DWT). This ...
0
votes
1answer
395 views

Flat vs frequency selective fading in MC-CDMA?

I am trying to simulate an MC-CDMA system. I have NXK matrix $S$ which consists of subcarriers ($s_n,_k$ represents subcarrier $n$ of user $k$) and KX1 vector $X$ consists of user symbols. So my ...
0
votes
1answer
2k views

Baseline Correction: What is the concept of a baseline shift and baseline correction?

I have a laser induced fluorescence signal data-set. Currently the processing pipeline performs baseline correction by manually moving the signal so that the initial point is at the origin. Is this a ...
0
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0answers
21 views

Binary vs 4-PAM PSD

I'm struggling to understand how you would form an expression for the PSD of a 4-PAM signal which is using rectangular pulse shaping. I understand for binary the likelihood of +/1 is equal so the ...
0
votes
1answer
392 views

How to convert the mean and variance of a processed received signal into a SNR or BER?

So I'm trying to eventually get some sort of signal quality metric, and to do that, I'm trying to take the mean and variance of my bit determination signal and use that to come up with a Signal to ...
0
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1answer
46 views

Separate speech signals that are bandlimitted

I have 2 kind of signals (refer figures) in a folder. One is band limited to 4khz and another is band limited to 8khz, both are with sampling frequency 16khz. I need to separate them. Any idea??
0
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2answers
52 views

negative value of signals

can we say there is no sound produced when the amplitude is 0? if yes what can we say when the amplitude is negative?
4
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1answer
557 views

How Exactly Does MATLAB Zero Pad Signal?

I am doing some massive number crunching in MATLAB which involves millions of PSD estimations. Each data segment has length 41. So I have been using the multi-taper method with ...
1
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2answers
353 views

Independent component analysis for one observation of a Signal

So I am a complete novice to ICA, so excuse my question if it is bad one, but I have the signal: $$\sin(2\pi x) + \sin(4\pi x) + \textrm{Additive White Gaussian Noise}$$ I want to try to separate ...
0
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0answers
18 views

What is k and n in this Discrete Hilbert Transform formula and how to use it with a time series?

I have a time series and I need to find the Discrete Hilbert Transform of that. This paper says that about the Hilbert Transform. Suppose I have a time series f(t)...
1
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1answer
27 views

Similarity in signal plots but dissimilarity in sensed content

I have two audio signals that look incredibly similar when plotted. However, when I play them, they sound quite different. The only difference I can even see in their plots is that one signal looks ...
0
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1answer
348 views

Why the energy is a good feature extraction for detect disturbances in signal processing?

To detect disturbances in signal processing a common step is to extract signal characteristics to analyze them, among these characteristics it is recommended to use the signal energy. Why energy is ...
0
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1answer
20 views

SNR of a pulsed signal in noise

I have a digitized acoustic data of length L in which a pulsed signal (chirp) of finite duration and bandwidth is merged starting at some time instant t1 and ending at time instant t2. I wan to ...
0
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1answer
382 views

Is there a way to obtain the transfer function from a bode plot on Python? (I know that it is possible on Matlab)

Quite simply, I have a bode plot obtained from a source signal. Now I wish to obtain the transfer function. I know it is possible with Matlab: http://www.mathworks.com/help/ident/examples/frequency-...
0
votes
1answer
40 views

EEG Sampling, Which Order should cover my result?

I have EEG data sampling rate is 250 Hz and I want to band pass this data in ( 0.5-3 Hz & 3-8 Hz & 8-13 Hz & 13-30 Hz & 30-40 Hz). Currently, the data is in the frequency range of ...
3
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3answers
3k views

Why do we get ripples in the frequency spectrum of a chirp, and how do I remove it?

The ripples in the amplitude spectrum of a linear spectrum is undesirable. I desire to obtain a flat spectrum response. Hence, how can I remove these ripples? Also, which factors (like time bandwidth ...
1
vote
1answer
55 views

Break a signal into segments, add them together and then perform an FFT on the result

If you break a 4 second signal into 0.5 second segments, add them together and then perform an FFT on the resultant 0.5 second data. Will the FFT / frequency spectrum be the simlar to an FFT on the ...
2
votes
1answer
534 views

How audio watermarks are captured

I have read that we can use audio watermarks to "identify the original produces of the material or the consumers of the media." How consumers of the media is measured by audio watermarks? Lets say ...
1
vote
1answer
54 views

Calculation of line of sight system gain

I'm trying to calculate the overall gain of the transmitter-receiver system for a line-of-sight wireless transmission. My question is how to calculate the overall gain of the system. Is it as simple ...
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0answers
14 views

The variance of the correlation output of a White Gaussian Noise and a BPSK signal?

Suppose the White Gaussian noise is $n(t)$ with zero mean and power density $N_0/2$. The BPSK signal is $b(t)\sin(2\pi f_c t)$. And $b(t)$ is the rectangular waveform as $$ b(t) = \sum_n B_n P_{T_c}(...
1
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2answers
1k views

Creating 2D array to play audio in left and right channel in matlab

I'm new to matlab sound processing and I am trying to create a 2D array for the sound code below. I have to make the sound have 400 samples(i.e 10ms) at 20hz, but having trouble getting the code to ...
1
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1answer
551 views

Apply band pass filter (BPF) before calculating the power of a signal (PSD)?

From my understanding PSD tries to give a good estimation on the power each frequency attributes to the overall signal power. If I am only interested in a frequency range $(\omega_0 \leq \omega \leq ...
0
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1answer
23 views

Any meaning to the magnitude of a FFT when audio is recorded using a PC?

I understand the theoretical meaning of the magnitude of a FFT from a mathematical sense. But what about when the sound audio is recorded using a PC microphone using a package like PyAudio, and FFT is ...
1
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1answer
74 views

What is discrete angular frequency?

I am currently reading a paper about speech enhancement. The paper uses Spectral Subtraction Method. On that section, The paper stated that ω is the "discrete angular frequency index of the frames" ...