Question (1) Alphanumeric data are entered into a computer from a remote terminal through voice-grade telephone channel of bandwidth 3.4 kHz and output SNR of 20 dB. The terminal would like to send 128 ASCII characters. Received
(a) Calculate the channel capacity
(b) What is the minimum transmission time to required transfer all characters over the channel without error?
(c) Using MATLAB, plot the channel capacity in b/s vs. SNR in dB when the SNR varies from 0 to 30 dB (e.g., 0, 3, 6, 9, 12, 15,...,30 dB). On the figure indicate the region where error-free transmission is possible.
Question (2) You are given the MATLAB script in the last page of this assignment to experiment with simple digital communication system. The system uses binary phase shift keying to transmit a given message over Additive White Gaussian Noise (AWGN) channel. In this computer experiment, you have control over the SNR. Using this script, you could observe the bit error rate (BER) and the received message. You are asked to set the SNR to various values and report the BER and received message for each SNR setting in the following table.
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SNR (dB)
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BER
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Received Message
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0
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3
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10
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20
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Question (3) Given the figure shown to the right: (a) Find the Fourier transform of the half- cosine pulse shown in Fig. (a), (b) apply the time shifting property to the result obtained in part (a) to find the spectrum of the pulse shown in Fig. (b), (c) what is the spectrum of the negative half-cosine pulse shown in Fig. (c), (d) find the spectrum of the single sine pulse shown in Fig. (d), (e) determine the null-to-null bandwidth of each pulse considered above.
Question (4) The rectangular pulse:
x(t)= 1: 0 ≤ t ≤ T
0: elsehwere,
is transmitted through a channel that can be modeled as a liner filter with impulse response: h(t) = δ(t) + aδ(t - r). Determine the response
of the channel and sketch it.
Attachment:- MATLAB Script for Question 2.pdf