Questions tagged [chirp]

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guidance for designing a pilot signal

Introduction I wish to design a pilot signal which will be used to estimate the channel, and will be sent prior to data, on a wireless acoustic link (underwater acoustic communication). I've been ...
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33 views

what is the the resultant, or, “final” frequency of the FFT of a chirped signal

Let's say we have a time-transient with a chirped signal, $$V(t) = \cos\left( 2 \pi f(t) t \right)$$ where $f(t)$ is the frequency of the signal and is time dependant. My question is how would one ...
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2answers
53 views

How to implement an RF Mixer for chirp signal in python?

According to this link, all I need to do to mix two signals is to multiply them. I have two chirp signals with same properties, one leading the other. If I multiply them to get the IF output, I don't ...
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1answer
138 views

Circular Convolution and FFT of power 2

I am currently trying to understand the Chirp Z Transform, and compute an FFT for a vector that has size which is not necessarily a power of 2. The key step in the Chirp Z transform to recognize that ...
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0answers
33 views

Prevent clicking noises during chirp generation

I am trying to generate a tonal sound which changes in frequency and amplitude over time. The goal is to emulate an engine order during driving. So I don't know the frequencies and the amplitudes ...
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101 views

What's the complex chirp signal?

I have a question. Why a chirp signal has the Fresnel ripples in slobes? I thought it has the equal amount of frequencies from lowerband to high band, so we should see the flat magnitude. Is that ...
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1answer
99 views

CZT: Do Bluestein algorithm perform backward transformation?

I am in discussion with one of my colleague that he says changing sign of the exponent in Bluestein's algorithm for Chirp-Z transformation, transforms the spectrum from frequency to time domain? I am ...
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1answer
105 views

Designing a Chirp in the Frequency Domain

I am trying to create a chirp signal in the frequency domain, by simply setting the magnitudes of each frequency bin to one, and then setting the phase delay function such that the resulting time ...
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0answers
34 views

Calculating chirp of a discrete signal

In the paper, The averaging method for finding exactly periodic dispersion-managed solitons , there is an expression for the chirp $C$ of a signal given by- $C = \frac{\text{Im}\int_{-\infty}^{\infty} ...
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43 views

Why does sampling chirp at peak frequency yield correct frequency response?

Followup; setting Fs = bandWidth in accepted answer's code yields the "correct" frequency response of an LFM chirp: constant magnitude, parabolic phase. ...
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3answers
263 views

Does chirp have constant magnitude frequency response?

Pg. 223 claims so, yet my results via DFT differ: Is the textbook wrong? My attempted explanations: (code) DFT vs DTFT: "frequency response" is computed via latter. Still, DFT should ...
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2answers
184 views

Complex nature of chirped signal

In a book on optical solitons, the author says that a Gaussian signal pulse has the form- $u(t) = \exp((\eta + i\beta)t^2)$ where $\beta$ is the chirp parameter. My question is: what does the $i$ ...
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1answer
130 views

How to perform dechirping of SAR image in MATLAB?

I have the transmitted pulse and the raw SAR image before range compression (dechirping). I understand the pulse compression its a convolution along the columns but I am not able to make it work. I've ...
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1answer
55 views

Detect playback position in swept sine sweep

I am wondering what the most precise method is to detect the playback sample position of a sine sweep? The real playback sample position is unknown and an DSP with constraint computing capabilities ...
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1answer
35 views

Detecting multi-path propagation when one acoustic signal is dominant

I am sending an acoustic signal from a source to a receiver where there are limited number of paths the signal can travel. I want to detect if there has been multipath propagation or not when one path ...
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1answer
162 views

On generalizing Gabor-Heisenberg uncertainty in a noisy environment

The Gabor-Heisenberg uncertainty represents the fundamental limit of time and frequency resolution one can extract from a signal. $\sigma_t \sigma_f \geq \frac{1}{4\pi}$ My question is: what happen ...
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1answer
254 views

Equation of wave in Linear frequency modulation?

We know that we have the following equation for wave. $$g(t)=A\cos(\omega t+\theta_0)=A\cos(2\pi ft+\theta_0)$$ The equation of frequency with respect to time will be: $$f(t)=\frac{Bt}{\tau}+f_c-\...
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1answer
452 views

Exponential Chirp

I'm trying to replicate in python the exponential chirp (here) but I cannot understand well the t and T in the formulas; here is what I wrote, but it is surely wrong, please could you help me? ...
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0answers
132 views

Chirp resolution as a function of bandwidth

My question concerns about the Chirp resolution during the crosscorrelation as a function of the sampling rate and available bandwidth. Suppose at a transmitter a chirp signal is transmitted (ranging ...
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2answers
559 views

Doppler Shifting A Chirp Signal

So I have a digital linear chirp signal: $$ x[n] = \sqrt{\frac{2}{N}} \cdot \cos\Big( 2 \pi \frac{f_{0}}{f_{s}}n + \pi \frac{B}{N} n^{2}\Big) $$ Where $f_{0}$ is the initial frequency, $f_{s}$ is ...
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1answer
152 views

Linear Chirp parameters from a segment of the signal

Edit:" please see the attached figure. The blue part is all I have. Also, you can neglect the noise term. Assume the signal is deterministic. Typical values of the unknown parameters $\alpha$ and $\...
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0answers
51 views

chirp z-transform for different output sizes

I am attempting to use the chirp z-transform for an application that requires arbitrary FFT output sizes less than or equal to the length of the input signal. However, I've encountered an issue where ...
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2answers
167 views

Cross-correlation peaks in acoustic multi-path conditions

Consider a speaker and a microphone are placed in a multi-path environment and the audio signal to be transmitted is LFM(chirp) signal, the time of arrival of the audio signal is computed by cross-...
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1answer
80 views

Phase of a signal with multi delayed windowed (rectangular window) signal with different amplitudes

I have a signal $x(t)$ which is composed of multi delayed linear chirps with different amplitudes and phases but they share the same $w$ and $\alpha$, the signal can be expressed as follows: $$\...
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2answers
692 views

Chirp signal FFT

I am doing some system identification using different signals such as single tone, multi tone, chirp and so on. These days I was trying to get an FFT of a chirp signal and I found a nice code here on ...
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1answer
683 views

Radar Imaging Method

I've been working with an FMCW Fast Chirp radar transceiver. Mainly, I've been looking at the Doppler range map but really it is not suitable as there is only one point per range/ speed and I want to ...
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2answers
1k views

Problems Using FFT to Compute Impedance in a Model Neuron

I'm a neuroscientist currently investigating the resonance properties of a single neuron model that a colleague and I have constructed. The language we code in is Julia, which I hope is similar enough ...
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2answers
815 views

Confused with filtering linear chirp signal using band-pass filter

everyone. Recently, I am doing simulations about filtering a linearly chirp signal, and have been confused about the result. The signal was linearly chirped from 0 to 1000 Hz. At first, the chirping ...
5
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1answer
2k views

Radar SNR for a LFM Waveform

How do you estimate the detection SNR for a radar transmitting an LFM (chirp) waveform? I'm looking for an SNR equation that is a function of chirp bandwidth and compressed (or uncompressed) ...
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1answer
163 views

Zero-pad to chirp signal

I have generated 16 chirps in experimental study: and the signal was picked up by some electronic sensor, and then I have calculated the spectrum of the received signal: Following that I have ...