Questions tagged [doppler]
The doppler tag has no usage guidance.
2
votes
2answers
78 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 ...
0
votes
2answers
51 views
Why having a ridge like Ambiguity Function implies lack of Doppler resolution?
I was wondering why if the AF (Ambiguity Function) has a ridge like form it has low Doppler resolution.
0
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1answer
23 views
Degrees rotation based on frequency offset?
What is the relationship to calculate degrees of rotation in the constellation given a baud rate and frequency offset?
0
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1answer
31 views
How to classify the movement type of a target into two categories(direct motion or else) by using a doppler radar?
How to classify the movement type of a target just into two categories(one is direct motion which is almost straight line movement and the other is anything else) by using a doppler radar with a ...
0
votes
2answers
114 views
In case of using a Doppler radar, do we have to use IQ demodulation to find the direction of a target?
I want to know the way to find the velocity of a target by using a doppler radar.
I read some paper about it,
In summary,
send rf signal to a target
receive the reflected signal from the target.
...
1
vote
1answer
98 views
Doppler Shift of Phase Coded Pulse Compression Waveform
Suppose I want to transmit the signal:
$$ x(t) = g\Big(\frac{t-t_{0}}{T}\Big) \cdot \cos(2 \pi f_{0} t + \theta_{0}) + g\Big(\frac{t-t_{1}}{T}\Big) \cdot \cos(2 \pi f_{1}t + \theta_{1}) $$
Where $g(...
0
votes
0answers
25 views
Confidence measure for GPS CA Code Acquistion
As a follow-on to this question, how do GPS receivers decide if they've successfully acquired the coarse acquisition (CA) code for a GPS satellite?
If it's based on post correlation SNR, what's the ...
0
votes
0answers
20 views
Doppler effect in single tap frequency-flat wireless channel
I have been dealing with Doppler effect in a wireless multipath channel
and a bit confusion about getting the frequency shift caused by doppler effect.
My question is as follows:
I have designed ...
4
votes
1answer
61 views
How to undo dynamic Doppler effect by software?
I have a signal affected by Doppler effect. In general, the Doppler effect changes the scale of the time and frequency domains. So, to undo this phenomenon, I am using a sampling rate converter. Two ...
0
votes
1answer
97 views
Measuring Amplitude of sound wave FFT
Please, pardon my ignorance. This may be a simple question, but I am still unable to explain what is happening.
I am using a turtlebot to listen to sound emitted from a stationary sound source.
My ...
0
votes
0answers
120 views
Understanding Jakes Doppler Spread [duplicate]
I'm trying to understand why the doppler spread leads to a U-shaped spectrum shown below.
From what I learn, Doppler spread is caused by the aggregate of Doppler effect on all multipath components of ...
1
vote
0answers
47 views
Doppler Shift and Wireless Access Points
I am trying to design and implement a system that would calculate the velocity of a hand motion in smartwatch.
The general idea is to calculate the Doppler Shift of each access point and find ...
1
vote
1answer
209 views
Why do signal have mirror signal after pure frequency shift?
In my Matlab code I have a simple simulation of FPGA with the ability to simulate doppler shift, and after I and Q components plugged into IQmod with some carrier freq.
In my Matlab code when I ...
0
votes
1answer
524 views
Use of complex numbers to calculate Doppler effect?
First of all, I'm a beginner in this field, please tell me if any of what I'm asking is too basic / can be found with some google research.
I have a situation with a static TX and a moving RX (v is ...
1
vote
0answers
241 views
How to calculate the doppler shift?
I am writing a QPSK receiver in MATLAB. In the transmitter part, I have generated random data using randi, QPSK modulated and pulse shaped using a RRC filter.
The ...
0
votes
2answers
1k views
How to interpret an Ambiguity function
I need to evaluate several different waveforms regarding their doppler tolerance, for use in a radar application. So I came across something called the Ambiguity function.
The following picture shows ...
2
votes
0answers
178 views
Help detecting target in pulsed radar signal
This signal is from the Pasternack $2.4\textrm{ GHz}$ development kit. The saved signal appears to be the pulsed waveform. It is sampled at $20\textrm{ kHz}$ for $4130$ points. I recorded a ...
0
votes
0answers
129 views
Facing trouble to find out doppler frequency from phase of a target
I am novice at signal processing. I have to find out velocity of a target. There are 10 received pulses with 2 targets. I demodulated them and filtered also and find out the target location also. But ...
7
votes
2answers
970 views
Interpretation of Clarke's Doppler power spectral density
What I understand of Doppler spread is that the relative motion between Transmitter (TX) and Receiver (RX) change the exposing time of signal. In rapport to a constant-distance TX-RX, a moving toward ...
2
votes
0answers
510 views
Pulse Doppler Radar: how to filter its Range-Doppler matrix?
I want to simulate a Pulse Doppler Radar with medium pulse repetition frequency (PRF about $100\textrm{ kHz}$, about $500$ pulses in pulse train).
It's rather powerful, and should discriminate ...
0
votes
1answer
72 views
Correcting for Doppler shifts at the speed of sound for a 800 MHz signal
I'm working with a system which is planned to reach velocities of about 340m/s. It's likely that we'll be using a frequency around 800 MHz for rx and tx. At these speeds, supposing a fixed source, the ...
3
votes
3answers
664 views
Matched filter loss due to frequency offset
I'm working with a pulsed radar signal which uses linear chirp pulses. I perform pulse compression by applying a matched filter of the simulated chirp waveform and recording the location and power of ...
0
votes
1answer
437 views
Radar: FMCW or CW
I purchased a Doppler radar that can run in both CW and FMCW modes. I don't understand how to operate the radar in FMCW mode. I would like to understand what I need to do to get my radar to run in ...
