what is QPSK

[jcbender]

What is QPSK and can i get it on either 4dtv or coolsat pro? thanks for any info JAYCEE

 

[Mr Tony]

QPSK definition

Phase-shift keying - Wikipedia, the free encyclopedia

Coolsat can as most FTA is DVB QPSK...4DTV is DCII (Digicipher II)

 

[VinceT3]

it's a type of modulation also refered as DVB-S and all fta boxes in the us support that modulation if I'm not mistaken, there are few that support 8PSK also known as DVB-S2.. though not much is on that modulation..

 

[aegrotatio]

I was wondering about DCII modulation modes myself. It is a variant of QPSK but has enhancements that ended up being not compatible with DVB-S either because the DVB forum rejected them or didn't know about them.
I found really interesting background on 4DTV/DCII modulation techniques here:
North American MPEG-2 Information

 

[Satellite Expert]

DCII is a method of signal encryption. It has nothing to do with type of modulation used.

 

[digiblur]

it's a type of modulation also refered as DVB-S and all fta boxes in the us support that modulation if I'm not mistaken, there are few that support 8PSK also known as DVB-S2.. though not much is on that modulation..

Kinda... there's DVB-S2 QPSK and DVB-S2 8PSK too.

 

[updatelee]

DCII is a method of signal encryption. It has nothing to do with type of modulation used.

DGII can be encrypted, or it can not be encrypted.

DGII uses QPSK but its a different standard then dvb-s, same as dss can use qpsk but is a different standard then dvb-s

I use my genpix to tune non-encrypted streams like those on HITS 99.0w, other dvb tuners will not be able to tune these, even though they are qpsk and not encrypted, they dont use the dvb standard. but they are defn NOT encrypted.

 

[agers]

pls help me understand and explain in "lay mans term" the QPSK modulation and QAM? thanks in advance.

 

[brentb636]

That's different.
QPSK has one date point per quadrature transmitted.
16 QAM has 4 data points per quadrature.
64 QAM has 16 data points per quadrature.

Think of that as "data density" . 64 QAM has a lot more data per second than does QPSK, but it suffers badly from bad conditions in the field, like excessive distance, non line of sight, signal breakup issues, because all those data points are harder to control and get back in the correct sequence. If you DO find you can use it however, it yields a great amount of data, great shots of hi speed action ( where QPSK falls down, it doesn't contain the same data per second ) . It's a good encoding scheme for HD under well controlled circumstances, otherwise QPSK is used for it's greater robustness, even though there's less data throughput.

A good class that covers this and related subjects is telecast almost daily on 97W, PIT, the AZCAR test facility, 11779H 3979-3/4 . The class is for analog sat truck techs, upgrading to digital, and is very enlightening.

 

[tvropro]

GI's DC-II came out with there own twist on QPSK that don't comply to the standard. It was designed before there was any standard. Couple interesting things, Digicipher uses AC3 audio always unlike DVB and it's cousin is OTA ATSC.