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Every signal transmitted by an SDR is a quadrature signal: the sum of two amplitude-modulated signals, with carriers that are in quadrature (one is at 90 degrees from the other). A bit of trigonometry shows that this is equivalent to an amplitude and phase modulated signal; in other words, a quadrature signal is equivalent to $A(t)\cos(2\pi f_c t + \phi(t))$....

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n_d = pd.DataFrame((data)**2) np.sqrt(n_d.ewm(alpha = 1).mean())

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As the OP has described, the noise as shown is AM noise only as the constellation points are not changing in phase at all. A double sided spectrum with symmetric sidebands in phase with the carrier is amplitude noise: Consider a reference carrier as 1 at angle 0 degrees for which we do the following to create sinusoidal sideband noise by adding to it a small ...

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I haven't checked the details fully but the OP's revised solution is correct. Once upon a time, I had posted a to a class webpage from 1998 where I had some lecture notes giving the answer but the link is now defunct because my University seems to have deleted that webpage from its servers. Anyway, the answer that I came with to the OP's question is P_e =...

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From google: 3G-5G appears to use OFDM —along with QPSK og QAM depending on channel conditions. WiFi 802.11b used some CDMA-dialect, 802.11a and g uses OFDM along with BPSK, QPSK or QAM. WiFi mainly use frequencies around 2.4Ghz, while cellphones have used lower frequencies around 900Mhz (due to larger distances). Both have recently added capability for ...

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