Premier Mounts CDM-600 specifications Available Baud Rates, Effect on Eb/No performance

CDM-600 Satellite Modem	Revision 7
ESC++	MN/CDM600.IOM

13.3Available Baud Rates

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

13.4Configuration

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).

13.5Effect on Eb/No performance

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.

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