CTC Union EOC-20, Руководство пользователя

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10. EOC Design For Coaxial
10.1 Rate vs. Attenuation rule of thumb
The expected rate between Master to Slave stations is determined by various elements:

Transmission power

Total attenuation between transmitter and receiver

Noise floor at the receiver

ISI of channel (Inter Symbol Interference -> Multi Channel System)
In general, the frequency response of the coax network components is nearly flat in the EoCNA
band (in some cases the specified frequency range of the components is not suited for EoCNA and
their behavior in the EoCNA band should be measured empirically). If the frequency response of the
channel is assumed to be flat, the ISI term vanishes and the effect of the channel is reduced to
attenuation. Assuming that the receiver's internal noise is the dominant noise and knowing the
transmission power, it is possible to estimate the expected line rate between two stations according
to the "link budget" – the sum of all attenuations in the signal path. Table 1 lists the measured line
rate for varying attenuation values for Coax
MUX Coax application (RG59)
Path attenuation [dB] Line Rate [Mb/s]
0-8 128
9-16 128
17-46 128
47-51 112
52-54 96
55-59 80
60-62 64
63 No connectivity
Table 1: Rate vs. Attenuation for Coax
a.) Recommend Each Master to CPE Modem attenuation range be less than 52dB.
b.) RG 59@20
°°°°
C operation @30MHz , Common Cable loss reference is 4.954dB/100 meters