 - Staggered quadrature phase-shift keying (SQPSK), also known as offset quadrature phase-shift keying (OQPSK), is a method of phase-shift keying (PSK) in which the signal carrier-wave phase transition is always 90 degrees or 1/4 cycle at a time. A phase shift of 90 degrees is known as phase quadrature.
In SQPSK, the data is placed alternately on two channels or streams called the I channel (for "in phase") and the Q channel ("phase quadrature"). A single phase transition can never exceed 90 degrees. This property contrasts SQPSK with conventional quadrature phase-shift keying (QPSK), in which the phase can sometimes change by 180 degrees (two 90-degree shifts in a single transition). The average magnitude of the phase transitions is smaller with SQPSK than with conventional QPSK. The result of the smaller average phase "jump" is an improved signal-to-noise ratio (SNR) and a reduced error rate.
SQPSK and QPSK are not the only methods of PSK in common use. In binary phase-shift keying (BPSK) there are two possible states for the signal phase: 0 and 180 degrees. In QPSK and SQPSK there are four possible states: 0, +90, -90 and 180 degrees. In multiple phase-shift keying (MPSK) there can be more than four possible states for the signal phase. An example is the use of eight phase states: 0, +45, -45, +90, -90, +135, -135 and 180 degrees. More than eight phase states are rarely used because that takes the signal complexity past the point of diminishing returns and the error rate actually increases.
 |
Learn more about Network Administration |
| Networking FAQ: These FAQs for networking will help you learn networking basics. |
| Network user management: Use this guide to learn how to manage problem users on your network -- from un-savvy Internet novices to toxic bosses -- to keep your network secure. |
| Troubleshooting -- 'Network Know-How' Chapter 17: Troubleshooting, Chapter 17 of 'Network Know-How,' shows tools and methods that identify and solve network problems. Use this chapter as a tutorial to fixing computer connections. |
| Network management frameworks: FCAPS and ITIL: Network management is a complex topic. Thus far, two frameworks exist that can be of some use for understanding and taming network management: FCAPS and ITIL. |
| Networking podcasts: Listen to our networking podcasts and learn more about technologies you need to know to keep your network running smoothly. |
| The IT Guy: Networking comics: In our networking comic series, the IT guy and his office coworkers encounter day-to-day network challenges. |
| LAST UPDATED: |
30 Jun 2007
|
 |
Do you have something to add to this definition? Let us know.
Send your comments to techterms@whatis.com
|
|
More resources from around the web:
|
 |
 |
| |
RELATED GLOSSARY TERMS
| Terms from Whatis.com − the technology online dictionary |
 |
AMTOR
(SearchNetworking.com)
|
|
availability
(SearchNetworking.com)
1) In a telephone circuit, availability is the ratio between the time during which the circuit is operational and elapsed time.
2) In a network...
|
|
|
Show me everything on 
