Fracarro KTX Mode D'emploi page 7

Signal-to-Noise Ratio (SNR) estimation
In order to obtain a given SNR with the K-series optical link (KTX and KRX), the following table should be
used. For each value of optical attenuation, the output level and the corresponding SNR at each possible
input level are displayed. The last row is used to determine the maximum input power per channel vs. the
number of channels.
Example 1: If the optical link has 5dB optical attenuation and 32 PAL channels need to be transmitted, the
last line shows that the maximum input level per channel is 93dBµV. If this power is applied the result is an
SNR of 52.5dB and an output level of 88dBµV per channel.
KRX
KTX
Example 2: If the optical link has 8dB optical attenuation and 13 PAL channels need to be transmitted, the
last line shows that the maximum input level per channel is 97dBµV. If this power is applied the result is an
SNR of 52dB and an output level of 86dBµV per channel. However, if the input power is lower than 97dBµV,
for example 93dBµV, to find the output level and the SNR you need to select the column two to the left which
shows 93dBµV. Then select the optical attenuation of 8dB within the column which gives an SNR value of
48dB and therefore an output level of 82dBµV per channel.
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