5.7 Design an STS switch for 128 primary TDM signals of the CCITT hierarchy (30 voice channels per input). Blocking should be less than 0.002 and the loading is 0.2 erlang per channel. How many time slot interchange modules are needed? What is the complexity of the switch? Repeat Problem 5.7 for a TST design.

Need a solu

Explain the QPSK modulation challenges and problems.

Q4. Consider the QPSK digital modulation scheme (a) What does the abbreviation QPSK stand for? (b) Sketch an I-Q constellation diagram for this modulation scheme. (c) State the number of bits per symbol. (d) If the bit rate that is achieved with this modulation scheme is 128 Mbit s-, what is the baud (symbol) rate?

3. a) What does TDMA stand for? What does it mean? Explain or sketch the concept. b) What is PAM? What does it stand for? Explain or sketch how the modulated signal looks like.

c) Draw a block diagram of a typical digital communications system including both transmit and receive paths and describe the nature of the signals generated by each of the blocks. Briefly describe what happens within the Modulator element and explain what is meant by the term 'up-conversion'.

7+6) This QUESTION FROM DIGITAL COMMUNICATIONS II course.

1- Consider a PCM system for a sinusoidal signal 2 cos2л 2000t. It is desired to represent this signal such that the signal to quantization noise ratio is 20 dB. Determine: (a) Sampling frequency required. (b) The quantizing step size. (c) The number of bits per word (per sample). (d) Bit rate and bit duration. (e) The channel bandwidth needed.

Please I need accurate answers , according to thr book the answers for STS part are (a) 41 , (b) 10828

Q4. Consider the 16-QAM digital modulation scheme (a) What does the abbreviation QAM stand for? (b) Sketch an I-Q constellation diagram for this modulation scheme. (c) State the number of bits per symbol. (d) If the bit rate that is achieved with this modulation scheme is 256 Mbit s, what is the baud (symbol) rate?