Even plain old wifi is fascinating in terms of signaling, they use ofdm, or orthogonal frequency division multiplexing to encode data. The whole concept is crazy.
To summarize, the waveform (sine wave) is measured by degrees from zero, where 90 is the peak, 180 is when it crosses the middle line again, 270 is the trough, and at 360 it returns to zero. What OFDM does is interrupt the normal sine wave and jump from 90 to 180 to encode bits.
What gets crazier is that this is divided into dozens of different positions that represent different bit encodings. Then they go more crazy and run… I think it’s 10 by 2mhz wide carriers, all doing this same thing (for a 20mhz wide channel width) to encode more data into the bandwidth.
Then they get more crazy and implement AM on top of it, so you get high power OFDM and low power OFDM divisions that can do upwards of double the symbols on the same carrier.
The wizardry to make all this work is insane, and the fact that we’ve mastered it to the point where we can sell wifi cards for something like $20 USD just kind of blows my mind. This is crazy to me!
Even plain old wifi is fascinating in terms of signaling, they use ofdm, or orthogonal frequency division multiplexing to encode data. The whole concept is crazy.
To summarize, the waveform (sine wave) is measured by degrees from zero, where 90 is the peak, 180 is when it crosses the middle line again, 270 is the trough, and at 360 it returns to zero. What OFDM does is interrupt the normal sine wave and jump from 90 to 180 to encode bits.
What gets crazier is that this is divided into dozens of different positions that represent different bit encodings. Then they go more crazy and run… I think it’s 10 by 2mhz wide carriers, all doing this same thing (for a 20mhz wide channel width) to encode more data into the bandwidth.
Then they get more crazy and implement AM on top of it, so you get high power OFDM and low power OFDM divisions that can do upwards of double the symbols on the same carrier.
The wizardry to make all this work is insane, and the fact that we’ve mastered it to the point where we can sell wifi cards for something like $20 USD just kind of blows my mind. This is crazy to me!