Hierarchal Modulation
1.Theory
Wireless transmission of image and video data in hostile mobile environments necessitates for a system which guarantees the quality of the data using effective error protection while at the same time ensures continues video streaming [1]. Unequal Error Protection is a technique which makes use of the fact that not all data in a video stream is equally important [1]. Based on the study first presented in [2], data can be divided into different categories based on its importance and assigned varying levels of error protection. This section focuses on the implementation of unequal error protection in the form of hierarchical modulation.

Bibliography
1. Unequal Error protection of H.264/AVCvideo Using Hierarchical QAM. Woodward, Ahmed B. Abdurrhman and Michael E. Srbija : s.n., 2008. Telekomunikacioni forum. pp. 593-596. 2. Broadcast Channels. Cover, Thomas M. 1972. IEEE TRANSACTIONS ON INFORMATION THEORY. Vol. 18. 3. A Recursive Algorithm for the Exact BER Computation of Generalized Hierarchical QAM Constellations. Pavan K. Vitthaladevuni, Mohamed-Slim Alouini. January 2003. IEEE TRANSACTIONS ON INFORMATION THEORY,. Vol. 49, pp. 297-307. 4. UEP Concepts in Modulation and Coding. Werner Henkel, Khaled Hassan, Neele von Deetzen, Sara Sandberg, Lucile Sassatelli, and David Declercq. [ed.] C. Kuo. s.l. : Hindawi Publishing Corporation, June 27, 2010, Advances in Multimedia, Vol. Volume 2010, p. 14. 10.1155/2010/416797. 5. On Enhancing Hierarchical Modulation. Shu Wang, Soonyil Kwon and Byung K. Yi. San Diego : s.n., LG Electronics Mobile Research. 6. On the General BER Expression of One- and Two-Dimensional Amplitude Modulations. Yoon, Kyongkuk Cho and Dongweon. 7, July 2002, IEEE TRANSACTIONS ON COMMUNICATIONS,, Vol. 50, pp. 1074-1080. 0090-6778/02. 7. A New Look at the Exact BER Evaluation of PAM, QAM and PSK Constellations. Alouini, Pavan K. Vitthaladevuni and Mohamed-Slim. Minneapolis : Telektronikk, 2002.

...Maxim > App Notes > Basestations/wireless infrastructure
Wireless and RF
Keywords: tutorial, QPSK, modulation, modulator, demodulator, demodulation
May 01, 2002
APPLICATION NOTE 686
QPSK modulation demystified
Abstract: Readers are presented with step-by-step derivations showing the operation of QPSK modulation and demodulation. The transition from analog communication to digital has advanced the use of QPSK. Euler's relation is used to assist analysis of multiplication of sine and cosine signals. A SPICE simulation is used to illustrate QPSK modulation of a 1MHz sine wave. A phasor diagram shows the impact of poor synchronization with the local oscillator. Digital processing is used to remove phase and frequency errors. Since the early days of electronics, as advances in technology were taking place, the boundaries of both local and global communication began eroding, resulting in a world that is smaller and hence more easily accessible for the sharing of knowledge and information. The pioneering work by Bell and Marconi formed the cornerstone of the information age that exists today and paved the way for the future of telecommunications. Traditionally, local communication was done over wires, as this presented a cost-effective way of ensuring a reliable transfer of information. However, for long-distance communications, transmission of information over radio waves was needed. Although this was...

...
Kirk Samuda
Institute of Advanced Technology
Devry University
September 2005
Advanced Telecommunication
To fully understand the advantages of the various modulation techniques of analog
signals, I think it’s important to understand the very basic premise on which modulation
exist. Allow me the privilege of starting with the basic function of any communication
system, which is transmitting information from one point to another. It may appear like a
simple process, however it is not. Consideration must be given to a conversation between
two people within close proximity, one speaks and another listens.
We already can observe some basic concepts of modulation, which reflects the power
of information as the sound of one person’s voice is dependent on the capacity of the lungs
of each individual reflected as a whisper, talk, or scream. The transmission medium that
carries sound from one person to another is considered either the air or free space.
It must be noted that the person who speaks (whoever that is) can be considered
the transmitter and the person listening is the receiver. Hence as the information, words,
sound is about to leaves the first person’s mouth it needs to be converted or changed
(modulate) then transmitted to the ears of the listener. The listener (receiver) must then
interpret the sounds heard or transmitted (demodulate) to...

...IC566 and IC565 and thus obtain the modulation of the carrier wave with respect to frequency of message signal. Frequency modulation is defined as the process of changing the frequency of the high frequency carrier signal with respect to low frequency modulating (message) signal which typically contains the information to be transmitted. The purpose of the carrier signal is to carry the message signal to the receiver through the space as an electromagnetic wave. We can impose the information on the carrier, so that we are able to alter the frequency and vary the signal strength by adjusting the carrier signal. Thus the variation of a carrier wave in accordance with the message signal is known as modulation. Demodulation is the process of recovering the original signal from the modulated carrier wave.
LIST OF FIGURES
S.NO.
TITLE
PAGE NO.
1.
FM Circuit diagram
2.
FM waveform
3.
IC 565 Pin diagram
4.
IC 555 Pin Diagram
INTRODUCTION:
Frequency modulation:
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. In analog signal applications, the difference between the instantaneous and the base frequency of the carrier is directly proportional to the instantaneous value of the input-signal amplitude.
Frequency...

...generation. (Armstrong method).
07
OR
(a) Draw the circuit diagram of ring modulator using diode and explain its 07
operation.
(b) Explain FM detection using PLL.
Q.4
07
(a) state and prove the following properties of Fourier transform:
(1) Time shifting (2) Frequency shifting
07
(b) An audio signal 15sin2ᴨ (1500t) amplitude modulates a carrier 60 sin2ᴨ 07
(100,000t).
i) Sketch the audio signal.
ii) Sketch the carrier.
iii) Construct the modulated wave.
iv) Determine the modulation index and percentage modulation.
v) What are the frequencies of the audio signal and the carrier?
OR
1
Q.4
(a) Determine the fourier transform of rectangular pulse shown below.
Q.4
(b) A 107.6 MHz carrier is frequency modulated by a 7 KHz sine wave. The 07
resultant FM signal has a frequency deviation of 50 KHz.
i) Find the carrier swing of the FM signal.
07
ii) Determine the highest and lowest frequencies attained by the modulated
signal.
iii) What is the modulation index of the FM wave?
Q.5
Q.5
(a) Write a short note on self-capacitance of a coil.
07
(b) Two resistors of 20 and 50 kΩ are at room temperature. For a bandwidth 07
of 100 kHz, calculate the thermal noise voltage generated by (a) each
resister, (b) the two resistors in series, and (c) the two resisters in parallel.
OR
A series circuit consisting of a coil and a variable capacitance having 07
(a)
reactance Xc. The coil...

... %m = [(100 - 60) / (100 + 60)] x 100% = 25%
3. A 500W carrier is to be modulated to a 90% level. Determine the
total transmitted power.
Solution: Pt = Pc [ 1 + (m2/2) ]
= 500W [ 1 + (0.92/2) ] = 702.5W
4. An intelligence signal is amplified by a 70% efficient amplifier
before being combined with a 10kW carrier to generate the AM signal.
If it is desired to operate at 100% modulation, what is the dc input
power to the final intelligence amplifier?
Solution: The efficiency of an amplifier is the ratio of AC output
power to DC input power. To fully modulate a 10kW carrier requires 5kW
of intelligence. Therefore, to provide 5kW of sideband (intelligence)
power through a 70% efficient amplifier requires a dc input of:
5kW / 0.70 = 7.14kW
5. A transmitter with a 10kW carrier transmits 11.2kW when modulated
with a single sine wave. Calculate the modulation index. If the
carrier is simultaneously modulated with another sine wave at 50%
modulation, calculate the total transmitted power.
Solution: Pt = Pc [ 1 + (m2/2) ]
11.2kW = 10kW [ 1 + (m2/2) ]
m = 0.49
meff = ²√ (m1² + m2²)
= ²√ (o.49² + 0.5²)
= 0.7
Pt = Pc [ 1 + (m2/2) ]
= 10kW [ 1 + (0.7 ²/2) ]
= 12.45kW
6. A TRF receiver is to be...

...
Prelab 3
1:
The operations involved in the modulation of DSB-SC are:
A message signal and carrier signal are fed in to a mixer which effectively modulates the message signal. The figure below demonstrates this step:
Mathematically, this is expressed as the following:
The resultant waveform can be demodulated by multiplying the modulated signal by the carrier signal of the same frequency and then using the low pass filter to filter out the remaining frequencies to get the frequency required.
In terms of the frequency domain, the following figure shows the effect of DSB-SC modulation
The effect of the demodulation process in frequency domain:
b)
AsAccos2πfstcos2πfct=AsAc2(cosfs+fc2πt+cos(fs-fc2πt))
xt=AsAc2cos(ωs+ωct+cos(ωs-ωct))Xω=AsAcπ(δω+ωs+ωc+δω-ωs-ωc)There are two distinct frequencies are (ωs+ωc) ,-ωs+ωcc)
AdAsAccos2πfct+ϕcos2πfstcos2πfct=AsAcAd2(cos2πfct+ϕcos(fs+fc2πt)+cos2πfct+ϕcos(fs-fc2πt))
AsAcAd4(cos2ωc+ωst+ϕ+cosωst-ϕ+cosωst+ϕ+cos2ωc-ωst+ϕ)After low pass filter the two 2ωc term sinusoids are filtered so:
AsAcAd4(cosωst-ϕ+cos(ωst+ϕ))=AsAcAd2cos(ωst)cos(ϕ)There is only one distinct frequency that remains after demodulating and low pass filtering: ωs. The effect of the phase shift is the multiplication of the output with a constant cos (Φ). Therefore one needs to know the phase shift of the demodulation signal in order to demodulate and get the original signal.
Q2:
Advantages of DSB-LC when compared to...

...Communication Systems
EEE F311
Contents
1
Aim of the course, what to expect?
2
Course content
3
Instructions about the course
4
Introduction/Discussions
Aim of the course …
Understanding signals and systems
Analog & Digital modulation/transmission
techniques
Understanding important block-sets of
communication system
Information theory
Analysis of communication systems
Recent trends in communication
References required
B.P. Lathi, Modern Digital and Analog Communication
Systems, 4th Edition, Oxford University Press, 1998
Simon Haykin, Communication Systems,5th Edition,
John Wiley & Sons, 2001.
References
Proakis John, Digital Communications, 4th Edition, TMH
K. Sam Shanmugam, Digital and Analog communication systems, John
Wiley & Sons
Evaluation components
Component
Date/time
T1
Duration
weightage
Nature
14/09
1Hr
04:00-05:00
15%
CB
T2
24/10
1Hr
04:00-05:00
15%
OB
Assignment/
Surprise tests
----
10%
OB
Lab regular (Perf ---+Report+Matlab)
3 Hrs
12%
OB
Lab compre +
Online Matlab
1.5 Hr+ 1Hr 13%
CB
3 Hrs
CB/OB
Compre
13/12/13
35%
Digital Communication lab - A-201
Equipped with DSO, AFG, DMM, Power
supplies
Trainer kits for all the experiments
supported by the softcopy of manual
One of the group-member should carry
laptop, will need to install MATLAB + certain...