Premier Mounts Modem CDM-600 사용자 설명서

CDM-600 Satellite Modem 

Revision 7 

ESC++ 

MN/CDM600.IOM 

13–2 

At the lowest data rates, the 11.76% overhead may not allow all baud rates. The 
following table shows available rates: 
 
Data rate 

 

 

Baud rates available 

64 to 127.999 kbps 

 

1200, 2400, 4800 

128 to 191.999 kbps 

 

1200 to 9600 

192 to 255.999 kbps 

 

1200 to 14400 

256 to 383.999 kbps 

 

1200 to 19200 

384 to 511.999 kbps 

 

1200 to 28800 

512 kbps and above 

 

1200 to 38400 

 
 

To use this mode, the user should select ESC++ from the CONFIG, MODE menu. The 
baud rate and async character format are then selected from the CONFIG, MISC, 
HIGH-RATE ESC menu. This is described in Chapter 6 (Front Panel Operations). 
 
 

Because, particularly at lower data rates, where the percentage overhead is large, the 
increase in transmitted data rate will cause a decrease in the Eb/No performance. 
Therefore, all of the published data concerning BER versus Eb/No needs to be modified 
according to the table below: 
 
Data rate 

 

 

Overhead ratio (percentage)        Eb/No degradation       

64 kbps to < 768 kbps   

19/17 (11.76%)  

 

0.48 dB 

768 kbps to 1.5 Mbps   

12/11 (9.09%)   

 

0.38 dB 

> 1.5 Mbps to 2.5 Mbps    

29/27 (7.4%)   

 

0.31 dB 

> 2.5 Mbps to 7 Mbps   

19/18 (5.56%)   

 

0.23 dB 

> 

7 

Mbps 

  64/63 

(1.58%) 

  0.07 

dB 

 
The degradation is simply 10 * log (Overhead ratio) 
 
The Eb/No displayed by the modem (MONITOR, RX-PARAMETERS) takes this into 
account in the value that is calculated.