Questions tagged [amplitude]

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1answer
34 views

Amplitude-and phasefunctions for a system

I am studying a course in signalanalysis and have run into som trouble with a exercise. I am to dimension the circuit below in such a way that the DC-amplification is 1 and that the frequencies $\...
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1answer
46 views

Can FFT tells us existance of same frequencies with different phases?

So I know that applying FFT on a time-domain signal, shows which frequency components exists and what amplitudes each frequency signal has. My question is, suppose the signal contains same frequency ...
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1answer
38 views

Calculating power of brain signals

I have a dataset that contains EEG (or MEG) recordings of brain signals during some cognitive tasks. Each row, shows the source estimates of neurons in a particular region. source estimate contains ...
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1answer
42 views

How is sampling affecting this sine wave?

I am trying to create a sine wave in python, but when I graph it, it looks like this: here is the code I used to make the signal: ...
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1answer
54 views

Bandpass filter equivalent for amplitude

I have a signal where I am using a bandpass filter to limit the frequency range. I am also interested in filtering the remaining frequencies (after bandpass filtering) within the signal by their ...
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1answer
37 views

Fine frequency correction : grouping and finding max amplitude inside a group

I work on phase and frequency estimation algorithm. Currently I am working on a derivation and determination of the Doppler shift( dF – frequency step). For each dF, The following algorithm was ...
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1answer
31 views

Amplitude / gain of difference of 2 known FIR low-pass filters

Given a discretely sampled sinusoidal signal (frequency $1/40$), and 2 Simple Moving Averages (SMA), better known as FIR low-pass filters of order e.g. $10$ and $21$, it can easily be calculated what ...
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1answer
27 views

RMS Amplitudes of voltage

I am looking here at the course of current fluctuations and have calculated the RMS values, but somehow it seems strange to me: with the black line there are small fluctuations, but the RMS value is ...
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0answers
29 views

Emulating tape distortion of low-level audio signals

I'm working on a tape echo emulation in Reaktor, and I've based the frequency response, tape speed warble, high-amplitude saturation and tape hiss on a paper I found about the Roland Space Echo. ...
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4answers
156 views

Amplitude of the fft is less than what is expected

This is my MATLAB code ...
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1answer
44 views

How to obtain the exact value of wavelength from a 2D FFT amplitude vs wavenumber plot like it is obtainable from 1D FFT amplitude vs wavenumber plot?

I have a two dimensional multi modal spatial signal generated from a MATLAB code using sinusoidal functions of different wave numbers, amplitudes and phases. What I want to know is that if I have the ...
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1answer
38 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 ...
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1answer
43 views

How to compute correct phase in FFT even after applying phase unwrap and zeroing round off error?

I am converting a time-domain synthetic 1D signal to frequency domain using MATLAB fft. In the frequency domain, the amplitude vs frequency plot is coming reasonable which means it is showing the ...
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0answers
27 views

1D amplitude spectrum with MATLAB

I have written the following code to calculate the amplitude spectrum of a test signal. ...
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2answers
74 views

Amplitude spectrum (transfer function) of signal?

I have one question related to finding amplitude spectrum (transfer function) of signal knowing that output signal is time derivative of input signal. I have the answer graph but I don't understand ...
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1answer
92 views

What is the x and y axis showing for this matplotlib.pyplot histogram of a .wav file?

The python code below generates a histogram from a .wav file, but what exactly does the histogram show? Is the x axis amplitude binned by sampling rate? Is the y axis a count of how many samples are ...
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0answers
44 views

Instantaneous amplitude of a constant frequency sine wave?

I am playing around with the Hilbert transform using Python's scipy.signal.hilbert package to better understand what the various instantaneous properties are given different input signals. One input ...
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1answer
46 views

Discussion of simulation results of a signal sequence: amplitude

I need your help in understanding if the simulation result is correct. I have simulated a random BPSK sequence that was upsampled and filtered with a raised cosine filter. The length of the filter is ...
1
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1answer
44 views

Calculating transmitter power from spectral density

I want to find out what is the real transmit power of my USRP 2922, unfortunately the only results I get when looking at the spectrum analyzer is the spectral power density. These are the results of ...
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1answer
42 views

What equation predicts the amplitudes of harmonics from a square/triangle/sawtooth/pulse oscillator?

I have seen pictures like this which depict the shapes of amplitudes from the various common types of audio oscillators: Similar pictures of spectra are shown here. I am attempting recreating these ...
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1answer
40 views

Is there an equation that will graph the shape or predict the maximum amplitude of a single sample impulse fed through a One-Pole LPF?

If you feed a single sample impulse of a given amplitude through a One-Pole LPF you get an envelope that looks like this: The output of the LPF from its peak will settle into an exponential decay ...
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1answer
56 views

How to describe voltage fluctuations

I am looking for a way to describe the properties of voltage fluctuations - is the RMS amplitude a suitable measure? Attached is a screenshot showing the random current fluctuations (in the case of ...
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0answers
24 views

Quantify the amplitude of fluctuations

I consider the potential of a nerve cell, which is -65mV. If I introduce a random noise source, for example, this leads to fluctuations (see attached picture). I would like to know what is a good ...
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1answer
40 views

Find which signal was transferred in 32QAM

I've been assigned to solve a problem for 32QAM signals. The thing is, there are little to none sources in my native language to get any decent information on the topic. The problem is (in its ...
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2answers
66 views

How to quantify amplitude of oscillations in marginally stable systems?

Transfer function pole on the Imaginary axis indicates that the system is marginally stable which in time domain can be represented as a sinusoidal motion with constant amplitude and frequency of the ...
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1answer
64 views

Relationship between amplitude and sampling rate

I'm loading a signal with librosa in python. With the original sample rate of 22050 Hz, i get the following waveplot: When i choose to resample my signal with the sample rate of 512 Hz, i get the ...
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2answers
589 views

Amplitude modulation vs sampling rate?

As a sampled tone's frequency nears $f_s / 2$, amplitude modulation grows apparent: ("Actual" curve in grey; blue is what we get if taking samples (dots) "at face value"). This is ...
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0answers
47 views

Establish instantaneous amplitude of signal

I'm using the YIN algorithm to establish the pitch of my humming / whistling voice. This is a time domain algorithm and gives me the instantaneous frequency as a function of time ($f(t)$). I now wish ...
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0answers
87 views

(Newbie question) Calculation DC-offset and RMS

Being a newbie on this topic I beg you to be indulgent to me if my questions should be kind of "too" simple ;-) For doing automatic analysis on my audio material I started calculating the ...
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1answer
166 views

Why the bandwidth in frequency spectrum of AM wave is 2fm and not 2fc?

We know, the instantaneous voltage of AM wave is: ...
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1answer
133 views

How do decibels scale with wave amplitude?

I know the decibel scale is logarithmic in nature. Given that at 1V amplitude the power of the sound generated by this wave is 80dB, what would the dB be for the wave with amplitude 0.4V? I'm trying ...
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1answer
76 views

why does the additive synthesis method for a triangle wave require amplitude scaling by 8/pi^2?

I had to make a bunch of band limited digital triangle waves recently, so I went to (where else) wikipedia for the equations. I noticed that there is a constant amplitude scalar of ...
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0answers
141 views

RMS of signal vs average amplitude

I am trying to estimate the average amplitude of some signal with frequency 6 Hz, sampled at ~300 Hz. See figures for a part of the signal and its dft calculated using matlab. I estimate the average ...
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0answers
19 views

Equalization of ultrasonic transducer [duplicate]

I am working with ultrasonic transducers with frequencies 100 kHz, one for transmission one for reception. The transmitted signals are chirps. I would like to measure the time of flight between ...
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0answers
24 views

modulation depth

When a value for the power dissipated by an AM signal is given, and the depth of modulation is also given. Then you are told to find the modulation depth required to increase the power to a higher ...
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2answers
115 views

Minimum value of G (Amplitude) that guarantees an error probability of at least $10^{-2}$ in a 32-PAM transmission system

pretty much new here. This question comes from an Online course quiz which i have already completed but cant seem to get a good sleep over, just because i cant figure it out. Below is the question ...
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1answer
592 views

What is the step response curve of a second order low pass filter? And what if it is set for resonance?

I am doing a lot of audio synthesis DSP where I need to use low pass filters to shape the decay of an impulse. I understand that a one pole filter fed a discontinuity, say from a steady state of 1's ...
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3answers
1k views

Understanding FFTs for simple Sin / Cos

this is my first question in this forum, and although I read several threads on this side and googled a lot I could not find the answer to my question (maybe it is too basic)? For anyone reading this ...
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1answer
59 views

Is there a way to break down a signal into its respective phases (4 in this case) to be later analysed individually

Is there a way to extract amplitude information but over 4 phases of the same frequency. That is, if the frequency is known could I extract amplitude peaks (between given values)in the time domain in ...
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5answers
379 views

Amplitude reduction of Simple Moving Average on sinusoid

When a -causal/non-centered- simple moving average filter (arithmetic mean) with length $n$, is applied to a sinusoidal curve with period $p$, and the resulting curve is compared to the original input ...
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2answers
42 views

Amplitude of a signal. [-1, 1] vs variants and MFCC implications

I've seen two sort of audio signals, one where the y-axis takes values between -1 and +1. I'd think this means 1 means loudest? Not really sure And the second one I saw goes between $-10 000$ and $+...
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0answers
58 views

frequency amplitude asymmetry

I want to calculate the frequency amplitude asymmetry between two signals, EEG signals in particular. As a result, I expect a value ranging from 0 to 1. I have some references regarding that, but it's ...
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1answer
160 views

Decimation with IIR filter altering amplitude of signal

I'm downsampling a signal through decimate (scipy implementation), but the result has a different amplitude than the original signal, which if I understood correctly, shouldn't happen. The original ...
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1answer
180 views

Normalizing white noise to match pink noise's amplitude at a given frequency?

I have a pinking filter which I am running white noise through to get pink noise. I would like to then mix the white noise with this pink noise, where the amplitude of the white noise will match the ...
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1answer
79 views

Amplitude estimation of sinusoid in known spiky spectral noise

What is the "best" way to estimate amplitude of a known-frequency sinusoid in the presence of known spiky spectral noise (i.e. noise comprising a few spectral peaks at known frequencies)? By "best", ...
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0answers
190 views

How accurate is Python's FFT?

I am getting started with Python's FFT. I tested it on a signal that is a sum of three signals, two of which have an eigenfrequency of the grid, the third one does not (but due to large no. of data ...
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0answers
119 views

Is there a way to filter out low volume content in an audio sample?

Imagine you are listening to a digital file that contains some random speech. Now, while you are listening to it, you also hear in the background (spatially) some low volume content, either noise, ...
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1answer
1k views

Amplify a signal and phase shift it by multiplying by a complex number

Still need help 25th October 2019 I have a real time domain signal contained in an array, it's just two different frequencies summed together. If I want to amplify this signal by 10 and phase ...
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1answer
65 views

Amplitude modulation in pure sine wave [duplicate]

I am generating sine wave in MATLAB with following code ...
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3answers
48 views

Characterization of transfer functions with no local peaks

Assume that you are giving an arbitrary amplitude frequency response $A(\omega)=|H(j\omega)|$ Is there a characterization that ensures that $A$ is monotone? i.e, $A$ has a global maximum at $\omega=0$...