Timeline for Convolution between a channel with real signal vs. channel with complex signal
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
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| Jul 5, 2021 at 13:23 | comment | added | MBaz | Yes, that is correct. | |
| Jul 5, 2021 at 9:22 | comment | added | New_student | I don't know if it's allowed for me to ask about details here or I should raise another question., but I wanted to say that according to your answer, in that case, the phase shift is known at the receiver, right? I mean if we are sure that our transmitted signal is real, and then we receive after the equalizer $I$ and $Q$, that part of $Q$ represents the phase offset, right? so we can get such way to compensate it in order to correct the phase shift. | |
| Jul 1, 2021 at 21:35 | history | edited | robert bristow-johnson | CC BY-SA 4.0 |
added 4 characters in body
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| Jul 1, 2021 at 1:30 | comment | added | New_student | I got it .. thanks again | |
| Jun 30, 2021 at 15:08 | comment | added | MBaz | In this case, the ouptut of the quadrature receiver is complex. However, you can still of course further equalize that signal to recover the in-phase, real signal. But that needs to happen after the quadrature receiver. As an example, say you transmit $(I, Q) = (1,0)$ and receive $(0.7, 0.3)$. Applying some equalization method you can still produce $(1,0)$ (a purely real signal). | |
| Jun 30, 2021 at 15:05 | comment | added | MBaz | You're welcome! In general, the transmitter and receiver have different carriers. Part of the reason is that their clocks are different (their measurements of "one second" are slightly different). Also, their initial phases are independent. On top of that, you have the phase shift caused by the channel delay. If there is one single received signal (as in a satellite or a wireline link), the receiver can compensate for all of those and produce a purely in-phase (real) signal. In most cases, there will be multiple reflections, each with a different phase shift. | |
| Jun 30, 2021 at 14:36 | vote | accept | New_student | ||
| Jun 30, 2021 at 14:36 | comment | added | New_student | Thank you so much for your detailed answer, but do you mean by the phase shift what is called CFO ? I got what you mean, but what's about if we correct that CFO effects before performing the equalization, does that mean the equalizer should have real signal too? | |
| Jun 30, 2021 at 13:57 | history | answered | MBaz | CC BY-SA 4.0 |