How to define or calculate the DAC output noise floor? The intention is to produce 100 MHz real IF out of the DAC. I would need to konw the noise floor, since it affects the noise level at antenna.
Is there a specific parameters in the DAC datasheet from whic I could calculate the noise floor?
Its is just one of the things that affects your noise floor. Nrmally you far out phase noise of the PLL will be more dominant ... taht's what I have usually seen.
6N gives the SNR for Nyquist ampling, normall DACs are over sampled, then you need to add the contribution due to oversampling.
I don't see that oversampling is implied with usual RF or video DAC.
To my opinion, spurious-free dynamic range (SFDR) would be a common measure to describe the noise floor. Apart from quantization noise that defines the theoretical noise minimum for an ideal DAC , nonlinearity is the major contribution.