Eq Channel Capacity Density (Channel Quality)
is the expected capacity density of the channel after equalization is applied in the transmitter (predistortion). It is computed as c(f) = log2(1 + SNR Signal-to-Noise Ratio(f)) bits/sec/Hz.
The X unit of this trace is tones and can be changed to Hz by setting Trace > DigDemod > Frequency Unit to Hz.
The channel capacity is affected by noise/interference. This can come from the transmitter’s noise figure (related to thermal noise, which is uncorrelated with the data) or from distortion (correlated with the data).
The longer the analysis interval, the more coherent averaging will reduce the contribution of uncorrelated noise on the channel capacity.
The optimal equalizers are available in the Inverse traces.
The non-averaged Eq Channel Capacity Density is shown in the Inst Eq Channel Capacity Density trace.
See Also
