数据通信练习题答案外教

1、ECTE 364 Tutorial 1 Exercises1. Assume a data stream is made of the binary sequence 0001100111. Draw the digital signals that result from using the following encoding schemes. · Unipolar using positive voltages for 1s · NRZ-L· NRZ-I · RZ · Manchester· Differential Manch

2、esterAnswer:2. What is the data stream does the following digital signal represent assuming Manchester encoding, assuming negative-to-positive transitions represent 1?TimeAnswer : 111011103. Repeat question 2 assuming differential Manchester encoding, where transitions mean 0s.Answer: 100110014. Ill

3、ustrate ASK encoding for the sequence 1011 using a sine wave and two amplitudes where 10 volts represents 1s and 5 volts represents 0s and using 3 cycles per bit interval.Answer5. Illustrate FSK encoding for the sequence 1011 using a sine wave and two frequencies where 0s are represented by a freque

4、ncy that is approximately twice the frequency used to represent 1s. Assume also that 1s are represented by 3 cycles per bit interval.6. Illustrate PSK encoding for the sequence 1011 using a sine wave and phases where a phase of 0 degrees represents 1s and a phase of 180 degrees represents 0s and usi

5、ng 3 cycles per bit interval.7. Show how Phase Shift Keying (PSK) can be used to encode 2 bits per symbol.Answer:1110Phase reference signal0100SignalBitsAcos(2fct+45o)11Acos(2fct+135o)10Acos(2fct+225o)00Acos(2fct+315o)01Note, the magnitude of each arrow or vector is equal to A. It is possible to use other phase angles, e.g.