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987 views

Why does frequency sweeping double the frequency?

You can generate a signal with frequency f with sin(2*pi*f*t) where t is time. Yet, when I ...
Aravind Voggu's user avatar
0 votes
1 answer
77 views

Chirp pulse train FFT

I'm trying to understand why the Fourier transform of a chirp pulse train looks the way it does. I will attach the result I get in MATLAB at the end of the question. I tried to develop analytically ...
Student2222's user avatar
4 votes
1 answer
330 views

What wavelength do we use when calculating the array manifold vector when transmitting LFM waveforms?

We know that the array manifold vector, also called the steering vector, for an M element array is given by: $$ \mathbf{a}(\theta, \phi) = [e^{-j \omega \tau_{1}(\theta, \phi)}, e^{-j \omega \tau_{2}(\...
The Dude's user avatar
  • 632
2 votes
1 answer
749 views

Can you please help me in generating a chirp signal in GNU radio by creating a module of your own?

I am currently working on a FMCW radar using a SDR I have done the simulations in python and am moving towards simulations on GNU radio. In python it was easy to generate a chirp, just use the scipy....
Raj Patil's user avatar
1 vote
1 answer
114 views

Quadratic Chirp Generating Little to No Effect

I am trying to implement a quadratic chirp on a gaussian pulse which has a 4 ps fwhm. I convert the pulse to the frequency domain using an fft and then encode a chirp with the following function: <...
user68185's user avatar
1 vote
0 answers
302 views

Dechirping in python

I have a piece of python code that creates a chirping signal and a downchirp signal. I would like to "dechirp" the chirped signal and my expectation is that doing so, I'll be left with a ...
Mart's user avatar
  • 195
0 votes
1 answer
122 views

What does it mean to find the steady state output in this case?

I have a given $h[n] = 0.96^n$ for $n \in \{0,1,...,119\}$ and a test signal $x[n] = \cos(0.05\pi n)$ for $n \in \{0,1,...,N_x -1\}$ where $N_x = 120,000$. Now, I can analytically find the output $y[n]...
Ahsan Yousaf's user avatar
  • 1,533
2 votes
0 answers
68 views

Cramer-Rao Bound for Time Delay given a Chirp Waveform with AWGN

In multiple sources (e.g. Richards, Mark A. "Fundamentals of Radar Signal Processing, Second Edition"), I come across the following expression for the CRLB for the time-delay parameter, ...
StackMonkey's user avatar
1 vote
1 answer
167 views

Chirped vs. unchirped pulse and Fourier Transform intuition

Suppose I have a gaussian impulse like in the picture below, given by $$Ae^{t^2/\sigma^2}e^{j\omega_0 t}$$ I can do an FFT, add a quadratic phase to it and go back to the time domain. This will ...
The Capacitor's user avatar
2 votes
1 answer
365 views

Do PSK/QAM modulators (e.g. 4G/5G) fundamentally use more energy per packet than CSS modulators (e.g. LoRa)?

Not sure if this is the right place or even the right question to ask, but googling did not get me much further, so here goes: I'm trying to assess whether the power consumed by an IoT device, based ...
mvds's user avatar
  • 123
-1 votes
1 answer
154 views

Bandwidth for a binary chirp spread spectrum system

Let's say data rate requirement for some application is 36Kbps. For a binary Chirp spread spectrum system, SF=6 is taken so that M=64. Time * bandwidth = 64. If binary 1 is represented as Upchirp and ...
SinC's user avatar
  • 1
1 vote
1 answer
194 views

Add chirp to time domain pulse

I have a Gaussian pulse $E(\omega)$ centered at 500 PHz with a bandwidth of 10 PHz. The pulse is transform limited initially. I am trying to add chirp, through multiplying the FT of $E(\omega)$ by a ...
Ryan's user avatar
  • 27
1 vote
1 answer
433 views

I am working on chirp signal generation using DDS in verilog . To generate the chirp signal do I need to change the limit of the 8 bit counter?

I want to generate linear frequency modulated (LFM) waveform or a chirp signal using DDS in verilog. I am not using DDS IP Core. I have created DDS module using 8-bit rate counter, a 12-bit address ...
halomi's user avatar
  • 23
1 vote
2 answers
476 views

Can someone help me with chirp signal generation using direct digital synthesizer(DDS) in verilog?

I want to generate linear frequency modulated (LFM) waveform or a chirp signal using DDS in verilog. I am not using DDS IP Core. I have created DDS module using 8-bit rate counter, a 12-bit address ...
halomi's user avatar
  • 23
2 votes
1 answer
150 views

Chirp zero crossings

I am generating a linear chirp in C code with a f0 , f1 and T. What is the most efficient way to solve where the zero crossings appear? Thanks
Developer R's user avatar
-1 votes
1 answer
643 views

Relation between bandwidth and amplitude of auto correlation of chirp signal

I am trying to understand the properties of chirp signals and their characteristics. I plotted the autocorrelation of a chirp signal in MATLAB. How can I compute the relation between the amplitude of ...
Manoj's user avatar
  • 1
2 votes
2 answers
370 views

End of chirp in phase 0

I would like the chirp to end in phase zero. Chirp time or end frequency may vary slightly. Now I'm checking the maplot output. I observe the same thing at the output of the sound card. In this ...
ka_ru's user avatar
  • 23
0 votes
0 answers
551 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 ...
Linkyyy's user avatar
  • 133
0 votes
1 answer
137 views

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 ...
Yair M's user avatar
  • 305
-1 votes
1 answer
95 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 ...
user27119's user avatar
  • 199
2 votes
2 answers
2k 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 ...
d9ngle's user avatar
  • 121
3 votes
1 answer
678 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 ...
darthsid's user avatar
  • 133
0 votes
0 answers
66 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 ...
Matthias La's user avatar
0 votes
0 answers
366 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 ...
John's user avatar
  • 61
1 vote
1 answer
310 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 ...
jomegaA's user avatar
  • 659
2 votes
1 answer
325 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 ...
Leccy PW's user avatar
0 votes
0 answers
76 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} ...
Paddy's user avatar
  • 195
0 votes
0 answers
91 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. ...
OverLordGoldDragon's user avatar
2 votes
3 answers
2k 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 ...
OverLordGoldDragon's user avatar
3 votes
2 answers
1k 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 $i$ ...
Paddy's user avatar
  • 195
-1 votes
1 answer
486 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 ...
benr's user avatar
  • 11
0 votes
1 answer
84 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 ...
pffelix's user avatar
  • 31
-1 votes
2 answers
100 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 ...
Stat7's user avatar
  • 99
-1 votes
2 answers
352 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 ...
pierebean's user avatar
0 votes
1 answer
1k 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-\...
Sepideh Abadpour's user avatar
1 vote
1 answer
1k 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? ...
BADWOLF's user avatar
  • 23
0 votes
0 answers
360 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 ...
peter's user avatar
  • 125
2 votes
3 answers
2k 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 ...
The Dude's user avatar
  • 632
0 votes
1 answer
274 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 $\...
Ahmad's user avatar
  • 3
2 votes
0 answers
92 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 ...
seanovsky's user avatar
0 votes
2 answers
223 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-...
WSL's user avatar
  • 59
0 votes
1 answer
88 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: $$\...
Ahmad's user avatar
  • 3
1 vote
2 answers
1k 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 ...
MarkoP's user avatar
  • 175
2 votes
1 answer
1k 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 ...
SeanJ's user avatar
  • 123
5 votes
3 answers
2k 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 ...
nguzman's user avatar
  • 151
2 votes
2 answers
1k 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 ...
Wenhui Yu's user avatar
5 votes
1 answer
3k 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) ...
random_dsp_guy's user avatar
0 votes
1 answer
245 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 ...
Mo Re's user avatar
  • 11