A communications system uses QPSK instead of binary PSK. How much bandwidth is saved

 

1. A communications system uses QPSK instead of binary PSK. How much bandwidth is saved?

 

2. A modem utilizes 8PSK modulation. If the modem’s baud rate is 24 kbps, what is the information rate in kbps?

 

3. A 16-QAM modulator with 2 voltage levels uses maps the symbols on equal phases on both voltage levels. Draw the signal space (constellation) for your assumed phase angles.

 

4. Compare the required bandwidth of 16-QAM with binary PSK.

 

5. A modem is designed to transmit at 100 kbps over a channel with 15 dB signal to nose ratio. Find the maximum symbols on the constellation of this modem.

 

6. Repeat the previous problem when the SNR is 35 dB.