Modulation scheme: Difference between revisions

From LinuxTVWiki
Jump to navigation Jump to search
No edit summary
(add dtv demod signal processing link)
(3 intermediate revisions by 3 users not shown)
Line 16: Line 16:
! [[Frequency Modulation]]
! [[Frequency Modulation]]
|-
|-
! style="background:#efefef;" | [[Wikipedia:Phase_modulation||PM]]
! style="background:#efefef;" | [[Wikipedia:Phase_modulation|PM]]
! [[Wikipedia:Phase_modulation|Phase Modulation]]
! [[Wikipedia:Phase_modulation|Phase Modulation]]
|-
|-
Line 52: Line 52:
! 8-state [[Vestigial Side Band Modulation]]
! 8-state [[Vestigial Side Band Modulation]]
|-
|-
! style="background:#efefef;" | [[Orthogonal frequency division modulation|OFDM<br>DMT]]
! [[Orthogonal frequency division modulation|Orthogonal frequency division modulation<br>Discrete multitone modulation]]
|}
|}



If you interested in the inner workings and the theory behind demodulators
for digital TV, there are some signal processing tutorials
at http://www.complextoreal.com/.

[[Category:Technology]]

Revision as of 23:30, 1 February 2006

The Modulator converts an input signal into a form suitable for RF transmission. The Demodulator recovers the original signal. Since the RF signal is a based sine wave oscillating around the transmission frequency, the Modulator has to modulate this sine wave in a way so that all information is transmitted and well-recoverable but only as little Bandwidth as allowed is allocated.

The more the Modulation Scheme modifies the original sine wave the more the Frequency of the RF sine wave will vary -- the higher the Bandwidth will be.


Analog Modulation Schemes
Shortform Name
AM Amplitude Modulation
FM Frequency Modulation
PM Phase Modulation


Digital Modulation Schemes
Shortform Name
BPSK Binary Phase Shift Keying
QPSK Quadrature Phase Shift Keying
QAM-16 16-state Quadrature Amplitude Modulation
QAM-32 32-state Quadrature Amplitude Modulation
QAM-64 64-state Quadrature Amplitude Modulation
QAM-128 128-state Quadrature Amplitude Modulation
QAM-256 256-state Quadrature Amplitude Modulation
8VSB 8-state Vestigial Side Band Modulation
OFDM
DMT
Orthogonal frequency division modulation
Discrete multitone modulation


If you interested in the inner workings and the theory behind demodulators for digital TV, there are some signal processing tutorials at http://www.complextoreal.com/.