Difference between revisions of "Quadrature Phase Shift Keying"

From LinuxTVWiki
Jump to: navigation, search
 
Line 1: Line 1:
A [[Modulation Scheme]] where the [[Phase]] of the modulated signal is modified by an angle of -135°, -45°, +45° or +135°. Thus 4 states (a two-digit binary symbol) can get expressed in every transition.
+
A [[Modulation Scheme]] where the [[Phase]] of the modulated signal is shifted depending on the incoming bitstream by an angle of -135°, -45°, +45° or +135°. Thus 4 states (a two-digit binary symbol) can get expressed in every transition.
  
 
In order to minimize the used [[Bandwidth]] allocated on the transponder the outgoing signal is usually filtered using digital [[FIR Filter]]s with smooth roll-off so that the high-order noise of the sudden state changes gets removed.
 
In order to minimize the used [[Bandwidth]] allocated on the transponder the outgoing signal is usually filtered using digital [[FIR Filter]]s with smooth roll-off so that the high-order noise of the sudden state changes gets removed.
  
  
''let's place a picture here...''
+
''let's place the famous four-modulation-point-phasediagram-picture here...''

Revision as of 22:53, 13 September 2004

A Modulation Scheme where the Phase of the modulated signal is shifted depending on the incoming bitstream by an angle of -135°, -45°, +45° or +135°. Thus 4 states (a two-digit binary symbol) can get expressed in every transition.

In order to minimize the used Bandwidth allocated on the transponder the outgoing signal is usually filtered using digital FIR Filters with smooth roll-off so that the high-order noise of the sudden state changes gets removed.


let's place the famous four-modulation-point-phasediagram-picture here...