help please

17.A distinction needs to be made between data rate (expressed in hits per second) and rate (expressed in baud) when signal encoding techniques are used. 18. Name three types of transmission impairment. 19. What does the Nyquist theorem have to do with communications? Calculate 20. What is the bit rate for a signal in which 10 bits last 20 us? 21.A device is sending out data at the rate of 1000 bps, how long does it take to send out a single character (8 bits)? 22. What is the bit rate for this signal? 16 ns Time