# All Questions

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16 views

### Help with literature pointers for improving estimation of underlying mean for signal with periodic noise

I am in the starting phase of a master thesis and are having some trouble finding a good starting point in the literature for my thesis. The aim of my thesis is to provide as good of an estimate as ...
17 views

Suppose, I sample a signal $z=\mathrm{e}^{\mathrm{i}\omega t}$ alternatingly in quadrature components $I=\mathrm{Re}(z(t))$ and $Q=\mathrm{Re}(\mathrm{e}^{\mathrm{i}\alpha}z(t))$. Thus my data array ...
26 views

### Train of impulses in frequency domain

Why compressing a train of impulses in time domain produce a wide-spaced train of impulses in frequency domain and vice versa? i want to know the intuition behind that.
20 views

### How can extract the cosine transform formula used for 2D by scipy.fft.dct

For the 1D cosine transform the documentation is clear in here, and I can reproduce it easily: The formula is: $$y_k= 2 \sum_{n=0}^{N-1}x_n \cos \left( \frac{\pi k(2n + 1)}{2N}\right)$$ and here it is ...
12 views

### What is the use of quasi logarithmic frequency distribution in multisine frequency signal in finding FFT

I'm using multisine but recommended to use quasi log frequency distribution to find out FFT. What is the advantage of using this?
11 views

### SVD versus PCA in signal analysis [closed]

What is the exact difference between Singular Value Decomposition and Principal Component Analysis (PCA)?
16 views

### Performing root-music, how do i retrieve frequency and phase data of a signal?

I'm trying an alternative method to the classical fft to do signal analysis. I perform root-MUSIC on a certain known signal + noise in matlab with the function 'rootmusic'. This gives gives the signal ...
14 views

### How to get a non-equally spaced FFT back into the time domain

I have a signal that I STFT and then filter using an ERB spaced filterbank. At some point after this I want to get the signal back into the time domain, how can I go about this? Using a standard iSTFT ...
21 views

### Bio-signal discontinuity after FIR filtering

I'm filtering respiration signal. I have a signal of duration equal to 10 minutes, so I decided to divided it into period of 10 s. I filtered each epoch with FIR filter, but I have discontinuities ...
30 views

### FFT of a stretched vector

Lets say I have a small size vector x=[a b c d]. Now I stretch this vector 3 times and I got x3=[a a a b b b c c c d d d]. What would be the relation between fft(x) and fft(x3)?
25 views

### Finding a signal piece presence in a noisy signal [closed]

I'm working on a problem where the original signal X has been trimmed in the parts and pieces of another noise signal E has been put inside. X = [x1, x2,...,xn] Y = [x1, e1, x2, e2,...,xn, en] I have ...
26 views

### Amplitude decrease in FFT at higher frequency for multisine

I am adding sine signals with different frequencies but same amplitude=100. Sampling frequency is 50MHz. I am not getting 100 in frequency domain for frequency 787KHz. At 1K, 3K I am getting 100 ...
83 views

### Implementation of CIC filter using floating point

I am trying to implement a CIC filter and was reading through the literature and found that CIC filter cannot be implemented using floating point. I am unable to understand why that would happen. The ...
39 views

### FFT padding to power of 2

I have a vector v1 of size N1, I want to pad it in a certain way until it reaches a size power of 2 (v2 of size N2). I need that the first N1 coefficients of the FFT output to stay the same as when I ...
10 views

### Source IO size “8” does not match sink IO size “4”

This is my first attempt at using GNU Radio. I am trying to do this example, which is a sine wave generator. The example works, so I am trying to connect the throttle block to the audio sink block. ...
13 views

### Python library for audio filtering, gating, and sound/silence detection

Is there a Python library that can do all of the following?: Band-pass filter; Noise gate, with different parameters set for different segments of audio file; Detect and count the number of discrete ...
25 views

### Equalization in CAR- Automotive Audio

Can someone tell me what is the purpose of CAR Equalization in audio and why before CAR Equalization ,gain adjustments are necessary ? Also why would someone use FIR filters during CAR Equalization ...
26 views

### Frequency response of chirp signal changes when extracting burst from repeating chirp waveform

I hope i can make myself clear enough, even though i might not be familiar with the right terms. Using GNU Radio, i created a chirp signal with a sawtooth signal source into a frequency mod block, as ...
26 views

### Digital Signal Quantized Processor Complexity

In “traditional” digital signal processing, the complexity is computed as a number of multiplication the operation requires, e.g. the computation of the N-point DFT via the decimation-in-frequency FFT ...
20 views

### Sampling and Demodulation question

if I have an analog modulated signal with a DSBSC modulation (modulation index 100%) as an input in my receiver and I want to convert it to a sampled signal, do I need to demodulate the signal (with ...
26 views

### Phase of the sine signal by finding FFT of it in matalb using angle

I am using sine signal with phase=0 an frequency=100KHz. Computed FFT of it. Using angle function and multiplied the result with 180/pi; But getting 90.36 at 100KHz frequency. Can anybody explain why ...
34 views

### Balance Fader in Digital Amplifiers

What is the purpose of Balance / Fader in a digital Audio amplifier? In a signal flow what is the most apt position to place balance and fader(for example after before a compressor unit or at the ...
29 views

### How to solve this question on SSB modulation? [closed]

A message signal $m(t)$ has components at frequencies of 100, 200, and 400 Hz. It is SSB-modulated on a carrier with $f_c = 100 kHz$. The resulting passband signal $u_p(t)$ is demodulated by first ...
14 views

### Data smoothing in temperature measurements from MLX90614 BCC IR sensor

I am trying to measure temperature with the MLX90614 BCC IR sensor for my project, and I am having problems with my precision requirement. I had taken data for 1 second then took the mean of these ...
14 views

26 views

### Processing signal [closed]

Processing signal , Sampling of Continuous-Time Signals
25 views

### What happens to the audio of a reconstructed signal if we remove too much frequency?

Assuming we have an audio with noise embedded in it, I was wondering what happens theoretically if we remove (filter out) too much frequency when we pass LPF with a cutoff frequency lower than the ...
30 views

### Accelerometer Bias estimation with kalman filter

I have to estimate biases of a 3-axes accelerometer by modyfying an existent kalman filter mounted on a drone. The biases are assumed constant. The filter has 9 states: position (xyz), velocity (xyz) ...
25 views

### What phase rotation occurs when you take the derivative of an audio signal?

If you take the derivative of an audio signal, it provides a 6 dB/oct upward sloping filter (increasing high frequencies / cutting low frequencies) all the way across the spectrum. What is the result ...
151 views

### How to find peak value of an analog signal efficiently after sampling in the digital domain?

I have a bandlimited analog signal for which I want to find the peak value in real time. The signal is sampled and processed digitally at just enough sampling rate. Since the peak of the analog signal ...
987 views

### Does the Shannon theorem not apply when the amplitude of a wave is changed faster than half the time period of the wave?

Shannon's version of the sampling theorem states that if a function contains frequencies all strictly less than $B$ hertz, then it is completely determined by giving its ordinates at a series of ...
34 views

### What is meant by “omega suppression” in a lock in amplifier context?

Can anyone explain what is meant by "Omega suppression" in lock-in amplifier discussions or specifications. I'm usually very good at web-searching, but have been unable to find anything ...
29 views

### Digital Filters

If I want to remove the baseline drift in my ECG signal, which digital filter should be used without distortion and shift in my filtered output? What are the necessary things I have to look for the ...
5 views

### Which Image pre-processing method is the best for Histopathology images? (H and E stained image)

I am working on classification of breast cancer histology images (Dataset:ICIAR BACH challenge 2018). But I don't really know which method is the best way to enhance the features of H&E stained ...
39 views

### Short Time Fourier Transform has different frequencies than Fourier Transform?

The reason we do the STFT is so that we can analyse for short segments of time how much of the components in the frequencies of the FT are present. However, it may be possible that completely ...
20 views

### Magnitude and phase of frequency response from Z-transform

I have been given a signal which I have completed the Z-transform for and have got: $H(z)=1-z^{-1}$. I need to find the magnitude and phase of this transform but am unsure on how to actually do this. ...
51 views

### QPSK demodulation

My objective is to demodulate QPSK signal. At this moment, my constellation in the best case looks like in the picture below: and the corresponding eye-pattern: Eyes are completely closed, which ...
19 views

### In OFDM, does the parameter time offset is important if there is only one mobile in the cell?

I am learning about OFDM, and in my reading, I have noticed that (mentioned everywhere) synchronization is a very critical aspect of OFDM. Here, I am writing in the context of time synchronization (...
28 views

### What is the difference between sampling over $-4\pi$ to $4\pi$ and 0 to $8\pi$

I see no difference in magnitude, but the phase plots vary significantly while using NumPy and MatPlotLib to plot. Looking at the phase plots, I feel like I'm missing something important. Also, I'm a ...
45 views

### Analysis of the ratio of two moving average filters

I have created a basic segmentation algorithm for 1-D signals (e.g. audio) based on a ratio of energy averages. The classification rule involves comparing the signal energy measured over a short time ...
126 views

### There is an implant in me, is there a way to identify the frequency it is receiving signals on?

There is an implant in me, is there a way to identify the frequency it is receiving signals on? I don't want to share the evidence and my reasoning for believing there is an implant in me, you can ...
39 views

### Reconstructing input from the output of a known discrete-time IIR filter

I have known discrete-time IIR filter. I pass a signal x(n) through the filter and obtain the output y(n). How would I design a filter to obtain x(n) from y(n)? In general, is it possible to design ...
I've been trying to get DFT from an impulse response, such as $(n+1)[u[n]-u[n-5]]$, but I don't have any clue of where I should start from Thanks