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https://www.satsig.net/cgi-bin/yabb/YaBB.pl VSAT technology and installation >> iDirect Forum: hubs and terminals >> About option file value of MODEM_PARAMETERS https://www.satsig.net/cgi-bin/yabb/YaBB.pl?num=1404746341 Message started by Robert on Jul 7^th, 2014 at 4:19pm

Title: About option file value of MODEM_PARAMETERS
Post by Robert on Jul 7^th, 2014 at 4:19pm

Good Morning to all.
Refer to value MODEM_PARAMETER of Modem 3000 Series.
I would like to know how I have to do to check the values that correspond to each type of modulation? For example rx_modtype 1 = QPSK, 8PSK etc. rx_modtype 2 =.
What would be the command or arguments to see that each value has meaning?
From already thank you very much

Title: Re: About Value of MODEM_PARAMETERS
Post by fluffymassive on Jul 17^th, 2014 at 5:59am

0 QPSK Rate 1/4
1 QPSK Rate 1/3
2 QPSK Rate 2/5
3 QPSK Rate 1/2
4 QPSK Rate 3/5
5 QPSK Rate 2/3
6 QPSK Rate 3/4
7 QPSK Rate 4/5
8 QPSK Rate 5/6
9 QPSK Rate 8/9
10 QPSK Rate 9/10
11 8PSK Rate 3/5
12 8PSK Rate 2/3
13 8PSK Rate 3/4
14 8PSK Rate 5/6
15 8PSK Rate 8/9
16 8PSK Rate 9/10
17 16APSK Rate 2/3
18 16APSK Rate 3/4
19 16APSK Rate 4/5
20 16APSK Rate 5/6
21 16APSK Rate 8/9

Title: Re: About Value of MODEM_PARAMETERS
Post by Eric Johnston on Jul 21^st, 2014 at 9:43am

I am trying to help someone.
I have similar questions for new iSCPC system:

1.
Extract from options file:
tx_mode = 2
tx_modtype = 1
tx_clksource = 0
tx_fecrate = 15
tx_scram = 1
tx_diff = 0
tx_specinv = 0
tx_power_in_dbm = -35.000000
tx_spreading_factor = 1
tx_spread_enable = 0

What is the above modulation type and FEC ratio ?

============
2� �Another question
Extract from options file:
tx_mode = 2
tx_modtype = 0
tx_clksource = 0
tx_fecrate = 18
tx_scram = 1
tx_diff = 0
tx_specinv = 0
tx_power_in_dbm = -2.000000
tx_spreading_factor = 4
tx_spread_enable = 1

What is the above modulation type and FEC ratio ?

=================
Best regards, Eric

Title: Re: About Value of MODEM_PARAMETERS
Post by Eric Johnston on Jul 21^st, 2014 at 11:19am

I think I have solved it. I got them to look at the iSite screen.

tx_modtype = 0� � BPSK
tx_modtype = 1� � QPSK

tx_fecrate = 15� � FEC=0.793
tx_fecrate = 18� � FEC=0.495

Is that right ?

Title: Re: About Value of MODEM_PARAMETERS
Post by fluffymassive on Jul 22^nd, 2014 at 5:30am

Hi Eric,

Looking at iSite like you have I presume when you select the drop down box for the MODCOD it will be either 0,1,2 and then the FEC drop down is then dependant on the MODCOD selected. if you used a process of elimination by selecting each type you could create a MODCOD/FEC grid

I.e.
MODCOD� � 0� �� 1� �� 2
FEC� �� 12� � 17� � 22
� �� 13� � 18� �23