naeem.ali
Newbie level 1
1. A digital communication system operating over an AWGN channel requires a probability
of bit error (Pb) of 10^-3, find the required Eb/No (dB) for the following binary
modulations: BPSK, BFSK, OOK, DPSK, non-coherent BFSK, and non-coherent OOK.
Show computations.
2. The bit stream (1 0 1 0 1 0 1 1 1 1 0 1 0 1 0 1 0 0 0 0 1 1 1 1) is to be transmitted using
DPSK modulation. Show four different differentially encoded sequences that can
represent the data sequence above, and explain the algorithm that generated each.
3. Suppose the bit duration is 1 ms. Calculate the minimum required bandwidth for BPSK,
OOK and non-coherent orthogonal BFSK.
4. Consider a 16-ary PSK system with symbol error probability Ps = 10^-5. A Gray code is
used for the symbol to bit assignment. What is the approximate bit error probability?
5. A bit error probability of Pb = 10^-3 is required for a system with a data rate of 100 kbits/s
to be transmitted over an AWGN channel using coherently detected MPSK modulation.
The system bandwidth is 50 kHz. Assume that the system frequency transfer function is a
raised cosine with a roll-off characteristic of r = 1 and that a Gray code is used for the
symbol to bit assignment.
(a) What Es/No is required for the specified Pb?
(b) What Eb/No is required?
6. If a system's main performance criterion is bit-error probability, which of the following
two modulation schemes would he selected for transmission over an AWGN channel?
Coherent 8-ary orthogonal FSK with Eb/No = 8 dB, or
Coherent 8-ary PSK with Eb/No = 13 dB.
(Assume that a Gray code is used for the MPSK symbol-to-bit assignment, and show
computations.)
7. A digital communication system must communicate over an AWGN channel with Pb
≦ 10-3 and bit rate Rb = 4 Mbits/s with a system bandwidth of 1.5 MHz and a signal-tonoise
ratio Eb/No = 12 dB. Assume that the system frequency transfer function is a raised
cosine with a roll-off characteristic of r = 0.5 and that a Gray code is used for the symbol
to bit assignment. What digital modulation do you choose for this system? Show
computations.
of bit error (Pb) of 10^-3, find the required Eb/No (dB) for the following binary
modulations: BPSK, BFSK, OOK, DPSK, non-coherent BFSK, and non-coherent OOK.
Show computations.
2. The bit stream (1 0 1 0 1 0 1 1 1 1 0 1 0 1 0 1 0 0 0 0 1 1 1 1) is to be transmitted using
DPSK modulation. Show four different differentially encoded sequences that can
represent the data sequence above, and explain the algorithm that generated each.
3. Suppose the bit duration is 1 ms. Calculate the minimum required bandwidth for BPSK,
OOK and non-coherent orthogonal BFSK.
4. Consider a 16-ary PSK system with symbol error probability Ps = 10^-5. A Gray code is
used for the symbol to bit assignment. What is the approximate bit error probability?
5. A bit error probability of Pb = 10^-3 is required for a system with a data rate of 100 kbits/s
to be transmitted over an AWGN channel using coherently detected MPSK modulation.
The system bandwidth is 50 kHz. Assume that the system frequency transfer function is a
raised cosine with a roll-off characteristic of r = 1 and that a Gray code is used for the
symbol to bit assignment.
(a) What Es/No is required for the specified Pb?
(b) What Eb/No is required?
6. If a system's main performance criterion is bit-error probability, which of the following
two modulation schemes would he selected for transmission over an AWGN channel?
Coherent 8-ary orthogonal FSK with Eb/No = 8 dB, or
Coherent 8-ary PSK with Eb/No = 13 dB.
(Assume that a Gray code is used for the MPSK symbol-to-bit assignment, and show
computations.)
7. A digital communication system must communicate over an AWGN channel with Pb
≦ 10-3 and bit rate Rb = 4 Mbits/s with a system bandwidth of 1.5 MHz and a signal-tonoise
ratio Eb/No = 12 dB. Assume that the system frequency transfer function is a raised
cosine with a roll-off characteristic of r = 0.5 and that a Gray code is used for the symbol
to bit assignment. What digital modulation do you choose for this system? Show
computations.