USRP Mathematics

If we consider usrp block chain for transmitting side. I have 3 questions
1-How I can describe the mathematical model for the signal for both real and complex signals in each stage in block chain?
2-If the input baseband signal for usrp transmitter larger than [-1 1] what could happen ?
3-what is the solution to make the signal proper as input in this case?

thanks

pls check the USRP clock, is it can do the telecom simulation? ITU allows the maximum offset is 5E-8