--- Quote Start ---
1- Do you mean that mapping values (+1000) changes according to DAC?
--- Quote End ---
The DAC dynmaic range is the ultimate digital point. So you make most of that range.
You have constellations at +/-1 for I/Q (normalised) you then scale it to DAC resolution
--- Quote Start ---
2- How does DAC relate to I and Q signals? They will be modulated with carriers, right?
--- Quote End ---
carrier modulation is system option. you can send your I/Q into separate DACs then modulate in analogue world.
or you can do some lifting from baseband inside digital domain
--- Quote Start ---
3- And you didn't answer my question about upsampling and how it goes
--- Quote End ---
use filter for upsampling. This is a bit involved area, basically you apply interpolating filter
--- Quote Start ---
4- One more thing, in regard to the last point of mapping, upsampling and shaping... is Raised Cosine filter one of these filters?
--- Quote End ---
yes when you implement as such i.e. as mapper, channel shaping and upsampler
and it does not need any mults in this case as you have few signal levels so you get your mutiplication pre-done in LUTs.
I know you need more details but what can I do?
Honored Contributor
