Changes between Version 80 and Version 81 of Other/Summer/2024/signal


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Timestamp:
Aug 6, 2024, 10:47:34 PM (7 weeks ago)
Author:
wesleychen
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  • Other/Summer/2024/signal

    v80 v81  
    128128After finding the frequency offset and phase, we can multiply each IQ sample by some exponential e^(-''i''*<delta>)^ where <delta> stands in for the error / angle offset of that sample. When multiplying numbers in the complex plane, the angle of the two are added allowing us to easily correct every sample. Now we see why complex numbers are useful. The corrected IQ samples are shown above right.
    129129
    130 == Architecture
     130== Results
    131131
    132 {{{#!html
    133 <img src="https://i.postimg.cc/9XrksKg0/temp-Image-KQMp-H4.avif" style="height: 200px;"></img>
    134 }}}
     132Earlier we saw BPSK working and get our message "hiii" back. We can do the same for OFDM. Here we receive our message "hi winlab"
    135133
    136 == Conclusions
     134[[Image()]]
    137135
    138 https://postimages.org
     136The ultimate goal is to send the two signals and see how they interact. This can very easily done by first blocking out the carriers we don't want to use in OFDM, then combining the signals simply by adding them.
     137
     138[[Image()]]
     139
     140Below is also the architecture for the entire transmission and reception process.
     141
     142[[Image()]]
     143
     144Now when we try to read the signals. We can still read the BPSK, but get garbage from the OFDM.
     145
     146[[Image()]]
     147
     148Here is also the error rates when OFDM and BPSK are at different levels.
     149
     150[[Image()]]
     151
     152We sent OFDM in 4 consecutive groups. Because the synchronization is interfered with, the first group is read ok, but the subsequent ones fail.
     153
     154== Final Regards
     155