Dear Professor, thank you for this detailed explanation. I have 3 questions and would be grateful to get responses from you or recommendations for what to read. 1. Is the modulation at the subcarrier level not actual modulation in the sense of varying some aspect of a wave (phase, amplitude, frequency, etc) to embed information? Is it simply a mapping between data bits and our choice of points on the constellation diagram? 2. From the IFFT module we get complex numbers e.g. a +bi. If we use 64 subcarriers, I understand that we would get 64 time samples i.e. 64 different complex numbers. Now how are these 64 complex numbers combined to form a single symbol to be sent? 3. For the actual transmission, does a (real part) modulate the cosine while b ('imaginary') part modulate the sine? in other words, what is the physical process for going from the complex time samples into physical voltage variations that results in RF emissions. The 5GHz oscillator you mention going to be split into one cosine and another sine (90 degrees out of phase), have these individually modulated and then the modulated sine is combined with the modulated cosine before finally being used to induce voltage changes at the antenna feedpoint..? Merci
Thanks for the help in understanding OFDM! ^^
Dear Professor, thank you for this detailed explanation. I have 3 questions and would be grateful to get responses from you or recommendations for what to read.
1. Is the modulation at the subcarrier level not actual modulation in the sense of varying some aspect of a wave (phase, amplitude, frequency, etc) to embed information? Is it simply a mapping between data bits and our choice of points on the constellation diagram?
2. From the IFFT module we get complex numbers e.g. a +bi. If we use 64 subcarriers, I understand that we would get 64 time samples i.e. 64 different complex numbers. Now how are these 64 complex numbers combined to form a single symbol to be sent?
3. For the actual transmission, does a (real part) modulate the cosine while b ('imaginary') part modulate the sine? in other words, what is the physical process for going from the complex time samples into physical voltage variations that results in RF emissions. The 5GHz oscillator you mention going to be split into one cosine and another sine (90 degrees out of phase), have these individually modulated and then the modulated sine is combined with the modulated cosine before finally being used to induce voltage changes at the antenna feedpoint..?
Merci
This was super good.