Paradise P300 specifications 12.4 Eb/No Explanatory Diagram, Summary

8.12.4Eb/No Explanatory Diagram

	Spectrum Analyser
1 Measure:	(C+N) / N dB
Carrier + Noise
Noise	Carrier+Noise
	Noise

	Symbol
From Satellite	Rate
Es = Signal / noise expressed
No	at the symbol rate

DEMOD

		Transmitted
		Bit Rate
Et	=	Signal / noise expressed
No		at transmitted bit rate

FEC

DECODER

Vit / Seq / TCM / Turbo

		FEC Decoded
		Data Rate
EDEC	=	Signal / noise expressed at
No		FEC decoder output rate

RS

DECODER

		Composite
		Information Rate
Eb	=	Signal noise expressed at
No		composite information rate

Rx Data

DEFRAMING

2Calculate ratio of Carrier power Noise power

	to
Carrier power	Noise power
	oC+N / Np

Each symbol represents several transmitted bits depending on the modulation:

BPSK = 1 Transmitted bit / symbol

QPSK / OQPSK = 2 Transmitted bit / symbol 8PSK = 3 Transmitted bit / symbol

FEC decoder reduces data rate

&corrects errors. Data rate reduced by FEC code rate:

1 / 2 Rate = 1 Decoded bit / 2 transmitted bits 3 / 4 Rate = 3 Decoded bits/ 4 transmitted bits 7 / 8 Rate = 7 Decoded bits / 8 transmitted bits 2 / 3 Rate = 2 Decoded bits / 3 transmitted bits

RS decoder reduces data rate & corrects errors. Data rate reduced by RS code rate:

k

Code rate n expressed as (n,k,t)

(126,112,7) = 112 Information bits / 126 Decoded

(219,201,9) = 201 Information bits / 219 Decoded

(225,205,10) = 205 Information bits / 225 Decoded

Bandwidth change due to framing is ignored in INTELSAT definition of Eb/No as Eb refers to the composite data rate.

o	C	p dB = 10 Log 10	o10		-1 p
				10
	N

3Determine Es No

Es	=	Energy per symbol	=		C
No		Noise power density		N

Summary

4

5

6

Es

- 10 Log (#Bits / Symbol) i

Et

Et

- 10 Log (FEC Code Rate) i

EDEC

EDEC

- 10

Log (RS Code Rate)i

Eb

No

No

No

No

No

No

BPSK

i

- 0 dB

1 / 2

Rate

i

+3 dB

(126,112,7)

i

+0.51 dB

QPSK / OQPSK

i

- 3 dB

3 / 4

Rate

i

+1.25 dB

(219,201,9)

i

+0.37 dB

8PSK

i

- 4.77 dB

7 / 8

Rate

i

+0.58 dB

(225,205,10)

i

+0.40 dB

2 / 3

Rate

i

+1.76 dB

1

2

oC+N / Np

3

4

5

6

Measure

i 10 Log10 o10

-1 p i o

C

Es

p- 10 Log (#Bits / Symbol)i

Et

Et

EDEDEC

EDEDEC

k

Eb

(C+N)/N

10

=

- 10 Log (FEC Code Rate) i

- 10 Log (

)

i

N

No

No

No

n

No

No

No

Example

i o5.40dBp - 3dB

6.5dB

i 2.40dB

2.40dB + 1.25dB

i3.65dB

3.65dB + 0.51dB

i 4.16dB

(QPSK)

(3 / 4 Rate)

(126,112,7)

P300H P300 Series Modem Installation and Operating Handbook Page 161