modulation

1. Advantages/disadvantages/applications of various modulation schemes
Advantages Disadvantages Applications
1. DSB-SC Lower power
consumption
The modulation system is
simple
Complex detection Analog TV systems: to transmit color
information
2. SSB-SC Better management of
the frequency spectrum
Low power consumption
The generation of exact SSB is
rather difficult.
Complex detection
Two way radio
Frequency division multiplexing
3. VSB-SC It is a compromise
between DSB and SSB.
Therefore it is easier to
generate than SSB-SC
Demodulation system is still
complex.
Its bandwidth is about 25%
greater than SSB-SC.
Analog TV broadcast systems
4.items 1~3 with
carrier
Envelope detection is
possible
Low power efficiency Wireless broadcasting systems
5. 8,16 level VSB-SC ATSC digital television standard＋
6. FM Increased immunity
to noise
Require a larger bandwidth Radio broadcasting; direct-satellite
broadcasting
7.PM Increased immunity
to noise
more complex receiving
hardware
data-communications systems
8.PSK Power efficiency. System
is the simplest
Low bandwidth efficiency Low speed communication
9. ASK Bandwidth efficiency Low power efficiency
10. M-ary PSK Require more bandwidth Transmitted power is lower V-32 Telephone data/fax modems
Satellite transmission of DTVB
programs.
11. QAM An attractive alternative
to SSB-SC.
Sharp cutoff band-pass
filters are not required.
Compared with SSB, QAM is
more exacting in terms of the
carrier frequency and phase or
the requirement for a
distortion-less transmission
medium
Used in cable communication for
the transmission of DTV and
internet traffic between cable
modem and modem termination
systems.
12. SHD AM/FM
RECEIVERS
Increased selectivity
against adjacent
channels
Interference from signal
frequencies close to the
intermediate frequency
Radio broadcasting
13. LINE CODES Power efficiency, Error
detection and correction
capability. Zero PSD at
f=0
Transmit only one bit of
information over the interval
of Tb second
Optical communications
14. M-ary PAM Transmits more bits in a
symbol time.
Require more power (M2
)
less system complexity
High rate data links
+
M.S. Richer et al,” The ATSC digital television system”, proc. IEEE, vol.94, pp.37-43, Jan, 2006.
www.atsc.org

2. AM Amplitude modulation
ASK Amplitude shift keying
ATSC Advanced Television Systems Committee
DSB Double sideband
DTV Digital television
FM Frequency modulation
PAM Pulse amplitude modulation
PM Phase modulation
PSK Phase shift keying
QAM Quadrature amplitude modulation
SC Suppressed carrier
SHD Superheterodyne
SSB Single sideband
VSB Vestigial sideband