Examples
1. The AM signal
is applied to the system shown in the figure below. Assuming that |kam(t)|< 1 for all t and the
message signal m(t) is limited to the interval -W f W and that the carrier fre
A continuous data signal is quantized and transmitted using a PCM system. If each data sample
at the receiving end of the system must be known to within 0.25% of the peak-to-peak fullscale value, how
Example:
1.
Let X and Y be statistically independent Gaussian-distributed random variables, each with
zero mean and unit variance. Define the Gaussian process
(a) Determine the joint probability densi
Examples
1. A pseudonoise (PN) sequence is generated using a feedback shift register of length
m = 4. The chip rate is 107 chips per second. Find the following parameters:
(a) PN sequence length.
(b)
Intersymbol Interference
Consider a baseband binary PAM system, a generic form
of which is shown in Figure 4.7.
The incoming binary sequence cfw_bk consists of symbols 1
and 0, each of duration Tb.
Transforms of Some Useful Functions
For convenience, we now introduce a compact notation for some useful functions
such as gate, triangle, and interpolation functions.
Unit Gate Function
We define a u
Examples:
1. For each of the following baseband signals: (i) m(t) = cos 1000t; (ii) m(t) = 2cos 1000t + cos 2000t;
(iii)m(t) = cos 1000t cos 3000t:
(a) Sketch the spectrum of m(t).
(b) Sketch the spec
Chapter 1: Random Processes
Chapter 1
Random Processes
Chapter 1: Random Processes
Random Processes
There are two distinguished classes of mathematical models:
deterministic and stochastic.
A model
Chapter 3
Pulse Modulation
Introduction
In continuous-wave (CW) modulation, some parameter of
a sinusoidal carrier wave is varied continuously in
accordance with the message signal.
In pulse modulat
Examples
1. The signal component of a coherent PSK system is defined by
where 0 t Tb, and the plus sign corresponds to symbol 1 and the minus sign corresponds to
symbol 0. The first term represents a
Chapter 4
Baseband Pulse Transmission
Introduction
Digital data have a broad spectrum with a significant lowfrequency content.
Baseband transmission of digital data therefore requires the
use of a l
Chapter 6
Passband Data Transmission
Introduction
In baseband pulse transmission, a data stream represented
in the form of a discrete pulse-amplitude modulated
(PAM) signal is transmitted directly ov
Coherent Frequency-Shift Keying
M-ary PSK and M-ary QAM share a common property:
Both are examples of linear modulation.
Coherent frequency-shift keying (FSK) is however, a
nonlinear method of passb
Quadriphase Shift Keying (QPSK)
In quadriphase-shift keying (QPSK), as with binary PSK,
information carried by the transmitted signal is contained
in the phase.
In particular, the phase of the carri
Differential Phase-Shift Keying
We may view differential phase-shift keying (DPSK) as the
noncoherent version of PSK.
It eliminates the need for a coherent reference signal at the
receiver by combin
Signal-Space Diagram of MSK
Using a well-known trigonometric identity in the equation of
CPFSK signal, we may express the CPFSK signal s(t) in terms
of its in-phase and quadrature components as follo
Chapter 3
Pulse Modulation
Introduction
In continuous-wave (CW) modulation, some parameter of
a sinusoidal carrier wave is varied continuously in
accordance with the message signal.
In pulse modulat
Examples:
1. Three telemetry signals, each of bandwidth 1 kHz, are to be transmitted simultaneously
by binary PCM. The maximum tolerable error in sample amplitudes is 0.25% of the peak
signal amplitud
Chapter 7: Spread-Spectrum Modulation
Chapter 7
Spread-Spectrum Modulation
Chapter 7: Spread-Spectrum Modulation
Introduction
A major issue of concern in the study of digital communications
is that o
Chapter 1: Random Processes
Chapter 1
Random Processes
Chapter 1: Random Processes
Random Processes
There are two distinguished classes of mathematical models:
deterministic and stochastic.
A model