Questions tagged [radio]

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3
votes
2answers
361 views

Quadrature modulation

I have a question: What is the difference between $ I \cos(t) - Q \sin(t) $ and $ I \cos(t) + Q \sin(t) $ except that they are phase shifted 90 degrees ? On the internet I can find both ...
5
votes
1answer
1k views

How do I convert a real baseband signal to a complex baseband signal?

I have radio telescope observations that have resulted in two real-valued signals (corresponding to the right- and left-handed circular polarizations). The signals are sampled at rate $2B$, and ...
1
vote
2answers
120 views

What is the relation between the carrier frequency and the attenuation of electromagnetic waves?

For electromagnetic waves, what is the relation between the the carrier frequency, attenuation (absorption loss) and propagation distance? I know that modulating high frequency carriers are required ...
0
votes
1answer
36 views

Wireless Channel Multiplicative Model

Let's assume a SISO channel in the equivalent baseband, the standard channel model (discrete) is: \begin{align} y(k) = h(k)x(k) + z(k) \tag1 \end{align} Where $y(k)$ is the detected signal, $h(k)$ ...
3
votes
2answers
808 views

Time Alignment of 2 Sensors Sampling the Same Signal with Different Hardware Delays

I have two radios sampling simultaneously, and I am trying to time-align their two signals (they will always start sampling at slightly different times with random delays due to hardware differences). ...
0
votes
0answers
84 views

Coming up with a squelch value

I am building a scanning-type system. I have samples in $\textrm{dB}$ and I want to determine when to allow them through. I am trying to decide between allowing them through when they reach a ...