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# Questions tagged [frequency-spectrum]

The frequency spectrum of a time-domain signal is a representation of that signal in the frequency domain.

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15 views

### Processing gain-frequency hopped

If you have a 3 MHz signal over a 3 GHz bandwidth, what would be the processing gain using a frequency hopping? What would be considered the hopping and the baseband?
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### Power spectral density of surface roughness

I am currently working on understanding how visually and intuitively the power spectral density is the fourier transform of the autocorrelation of a signal. I was wondering if anyone had a good ...
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### Clarification regarding discrete wavelet transform

One of the books on "Conceptual Wavelets" by Fugal explains some major differences between the undecimated discrete wavelet transform (UDWT) vs. discrete wavelet transform (DWT). In UDWT the scale of ...
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### Transmitting image in certain spectrum without mirroring

I have a problem because I want to transmit string at certain frequency that is simple .png with 0 and 1. I simply take height and width of the image and scale it to the bandwidth and time. Then I ...
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### Creating uneven sidebands with AM + PM modulation?

I am trying to modulate an optical signal such that I create a pair of sidebands with arbitrary phase and amplitude with respect to each other. For example I would be like to be able to modulate my ...
393 views

### The spectrum of the sum of two periodic signals

Considering the continue, periodic signals $s_1(t)$ and $s_2(t)$, with the period $P_1$ and $P_2$ respectively. Consider now a new signal $s$ the sum of the two pervious signals. I come to know ...
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### Scaling Function in Wavelet Analysis

I was watching a YouTube tutorial on wavelets https://www.youtube.com/watch?v=wgRgodvU_Ms, where the presenter showed that if we multiply a Gaussian with a sine wave (and follow some other conditions),...
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### How to detect harmonics on a frequency spectrum?

How are harmonics (fundamental or not) of a speech or music signal detected from its frequency spectrum? By frequency spectrum I mean the absolute value of the FFT of the audio signal.
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### Advantages of the Rotation Translation Operation Before Doing FT Smoothing

I was reading a relatively old paper from the 1970s on smoothing by FT methods (chemistry applications), where the authors show that if we do rotation translation operation on the signal (y- values) ...
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### Direct Digital Synthesis - Super Sampling - Unknown Harmonics

I'm using a Xilinx FPGA (Virtex) with 4 DDS cores (each supplied a 250MHz clock) used in parallel to provide a samples to a DAC38J82IAAV from TI, 16 bit DAC running at 1 Gsps. The four cores super ...
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### Why does downsampling stretch a signals frequency response and upsampling shrink and create images of a signals frequency response?

I am learning some basic DSP and I have a pretty good intuition as to why sampling creates spectral images of the frequency response at intervals of the sampling frequency (convolution with pulse ...
49 views

### What should be my sampling frequency?

I have an accelerometer that I am reading the x, y, z values for m/s^2. I've written up my code in Python as follows. ...
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### How to find fundamental frequency of two signals?

I am facing difficulty with finding fundamental frequency of signals I mean by fundamental frequency=(1/Time period) Correct me if I am wrong consider two continuous time signals with Time period ...
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### Spread Spectrum (CDMA) signal phase noise measurement

A CDMA signal is considered for this application. I would like to have an information on the generated signal oscillator's quality using a phase noise measure. If the signal was a pure carrier, it ...
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### How to normalize data by mapping data points from one mixture of multivariate normal distributions to another

Problem description I am trying to normalize multivariate time series data. The individual data sets (spectrograms from temporal EEG) comes from sources that differ widely in their noise ...