EXAMPLE1:DVB-S
Calculations for Bandwidth = 36 MHz, DVB-S, QPSK-7/8, Roll off Factor:
0.20
Symbol rate= BW/ (1+Roll Off)= 36/1.20= 30
Msps
Datarate= Sym. Rate X Modulation
Index X FEC X 188/204
=48.38 Mbps
Note:-
modulation Index – for QPSK is 2 and for 8PSK – 3 and for 16PSK -4
modulation Index – for QPSK is 2 and for 8PSK – 3 and for 16PSK -4
EXAMPLE2: DVB-S2
Calculations for 36 MHz, DVB-S2, 8PSK-7/8, Roll off Factor:
0.20
Symbol rate= BW/ (1+Roll Off)= 36/1.20= 30
Msps
Data rate, Mbps = Symbol rate X LDPC X BCH *modulation index because it uses BCH and LDPC (low-density parity check) for error correction.
roll-off factor – usually for DVB-S2 is 0.2
modulation Index – for QPSK is 2 and for 8PSK – 3
LDPC – the available LDPC values are: 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 8/9
BCH -- The value is approximately=0.98
Data Rate=30 X 7/8 X 0.98 X 3 = 77.175 Mbps
how can i calculate mux bitrate
ReplyDeleteaddition of all compressed(mpeg-4/mpeg-2) channels given to MUX +audio bitrate of all channels
DeleteWhat is user data? Data rate or Symbol rate?
ReplyDeletesymbol rate, also known as baud rate and modulation rate, is the number of symbol changes, waveform changes.The symbol rate is measured in symbols per second.
ReplyDeletesymbol rate= bandwidth(mhz)/1+roll off factor
Data rate = sy.rate * FEC * mod.factor * 0.92157
where mod.factor = 2 for DVB-S
Dta rate units is Mbps or KBPS or BPS(bits per second)
ReplyDeleteSymbol rate units is Msps or ksps or sps (symbols per second)