Questions tagged [complex]
The complex tag has no summary.
177 questions
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Is sampling a signal with 2-channel ADC, where the second channel is delayed by 90° at sampling frequency actually I/Q sampling?
So if I understand things correctly, in traditional I/Q sampling, we'd have our input signal, which passes through a quadrature splitter, and afterwards, at the splitter's output, we'd have 2 ADC ...
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Aliasing for undersampled complex signals
Physicist here with a simple question about undersampling for complex frequencies. In particular, supposing I undersample a pure complex sinusoid $e^{i\omega t}$, I want to know the frequency/phase of ...
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It is possible to generate $e^{i \omega t}$ in practice?
The signal $$e^{i \omega t}$$ where $i = \sqrt{-1}$ and $\omega = 2 \pi f$, is very useful in signal processing because it has a single frequency and the frequency response of a system is defined with ...
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Correct method for frequency shift and processing
I am trying to model the interaction of two signals and for various reasons, am trying to do it in the complex baseband domain.
Signal-A is a complex baseband signal (no frequency symmetry around $f=0$...
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How does a real 1D signal gets turned into an complex electromagnetic wave through an antenna?
For example, imagine a person speaking on a cellphone. A transducer converts air pressure into a voltage signal. This voltage signal should still be a real 1D signal in time.
To transmit this 1D ...
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2
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Discrete Version of Euler's Formula
We know the continuous version of Euler's formula:
$$ e^{i\theta}=\cos(\theta)+i\sin(\theta)$$
Since $\cos(\theta)=\sin(\theta+\frac{\pi}{2})$, we get:
$$ e^{i\theta}=\sin(\theta+\frac{\pi}{2})+i\sin(\...
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After finding that $e^{it}$'s image by a TILS is an exponential of the same periodicity, how to prove $\cos$'s image is $\cos$? Sinusoidal fidelity
I am trying to prove that the image of a cosine by a Time-Invariant Linear System is a cosine.
I start with $$\cos(t) =\frac{e^{it} + e^{-it}}{2} =x_1(t) + x_2(t)$$
Let's call the image $y_1(t) + y_2(...
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How to sum complex exponentials to produce a signal in python
I've got a signal with known shape (from Oppenheim and Willsky problem 3.22a.(b)). I solve for the Fourier coefficients analytically and am happy with their values, given by.
$$ a_0 = 1/2 $$
$$a_k = \...
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110
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Visualizing complex baseband signal
I am trying to visualize complex baseband representation of two signals, something like the below image,
The spectrum is not symmetric and contains two different frequency information, i am trying to ...
- 109
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Complex Spectrogram Interpretation
Given chirp signal like this:
Performing complex spectrogram function, returning real part and imaginary part:
...
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277
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Meaning of the phase of a sample
In a sampled signal RF signal with I,Q parts, if we represent each sample as an amplitude and phase, what does the phase of a sample mean? Does it say something about the RF signal at that point of ...
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How to demodulate Binary Offset Carrier Signal?
I need to modulate and demodulate a BOC (Binary Offset Carrier) modulated signal.
I tried starting with:
...
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Orthogonal signals basics [closed]
Suppose we have 2 orthogonal signals $x_{1}(t)$ and $x_{2}(t)$ and we add them up.
Can we always say that the resulting signal will be of this form:
$$x_{3}(t)=x_{1}(t)+jx_{2}(t)$$ ?
If that is true ...
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How can we treat real signal as imaginary?
I'm studying MRI and I couldn't understand this assumption(?)
The sentence 'The signal from one channel is no more or less "real" than that from the other channel.' Does not make sense to ...
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(graphic) Relation between FFT and complex signal
I have a complex signal with a frequency between 0 and 16 (16 not included).
I have made four plots (in python) to show four examples. For each example I provide the signal, its FFT in both real, imag ...
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