EE161 - Spring 2014
San Jos State University
e
Solution of Homework # 8 (Midterm 2)
1+
1. (a) The bandwidth of this system is given by B =
= (1 + )Rs = 40 106 Hz.
T
B
Therefore, the symbol rate is Rs =
= 36.36 106 baud. The modulation scheme
1+
(mapping)
EE251 - Spring 2014
San Jos
e State University
Solution Midterm Exam # 1
Problem 1 (30 points) A 100 Mbps binary communication system utilizes polar mapping with
Manchester pulses (Manchester code).
(a) Sketch carefully the waveform s(t) associated with t
EE251 - Spring 2013
San Jos State University
e
Solution of Midterm Exam # 1
Problem 1 (35 points) An AWGN signal with N0 = 2 109 W/Hz is input to a lowpass lter
of frequency response as sketched in the gure below. Let N (t) denote the output of the lter.
EE251 - Spring 2011
San Jos State University
e
Solution of Midterm Exam # 1
Problem 1 (50 points) A zero-mean AWGN signal X(t) of power spectral density 1108 W/Hz
is input to an ideal bandpass lter with transfer function
cfw_
1, |f fc | < 50 106 , fc = 1
EE161 - Spring 2013
San Jos State University
e
Solution of Midterm Exam # 2
Problem 1 (35 points) A wireless communication system operates at 16 Mbps over a non-fading
channel with a center frequency of 2.5 GHz. The modulation scheme is 16-QAM and a raise
EE161 - Spring 2011
San Jos State University
e
Solution of Midterm Exam # 2
Problem 1 (40 points) A binary (7,4,3) Hamming code is used in a binary communication system.
The parity-check matrix is given by
1
H = 1
1
1
1
0
0
1
1
1
0
1
1
0
0
0
1
0
0
0.
1
(a
EE161 - Spring 2014
San Jos State University
e
Solution of Midterm Exam # 1
Problem 1 (25 points) A binary communication system uses polar mapping and NRZ pulses.
The bit rate is 100 Mbps.
(a) Three bits are sent through an AWGN channel. The correlator ou
EE161 - Spring 2013
San Jos State University
e
Solution of Midterm Exam # 1
Problem 1 (35 points) A binary communication system uses polar mapping and the pulse
shape (t) sketched in the gure below. The bit rate is 50 Mbps.
(t)
sqrt(2/T)
0
T/4
T/2
EE161 - Spring 2011
San Jos State University
e
Solution of Homework 4 (Midterm exam # 1)
1. (a) Sketch:
s(t)
0
0
1
0
1
2Eb/T
t/T
1
2
3
5
4
(b) The vector of correlator outputs y = (y1 , y2 ) is closer to s2 , associated with a bit
value B = 1. Therefore,
EE251 - Spring 2012
San Jos State University
e
Solution of Midterm Exam # 1
Problem 1 (35 points) A four-level quantizer has a midtread characteristic with = 1. The
inputs are random samples M uniformly distributed in the interval 1 < M 1.
(a) Find and sk