## Example 4.2

#### A cabled binary baseband data system that supports a maximum information transfer rate of 1200 bps using bipolar signalling has to be modified to allow ac coupling of the receiver unit owing to dc offset problems in the circuit design. How might the system be altered to fulfil this task, and what would be the impact on the information transfer rate?

### Solution

#### An effective ac coupling method is Manchester encoding of the data which eliminates long strings of 1s or 0s . Manchester encoding, however, doubles the occupied bandwidth of the data signal and hence the usable data rate would drop from 1200 bps for bipolar signalling to 600 bps for Manchester encoded data transfer.