Feed-Forward Equalization

Figure 1: FFE creates a number of delayed versions of the
input signal that are then added back to the signal with
proper weights

In addition to continuous time linear equalization (CTLE), another means of improving signal quality at the receiver end of a high-speed serial data link is known as feed-forward equalization (FFE). In terms of implementation, FFE is not unlike the pre-emphasis filtering that is done on the transmitter side. An FFE implementation looks for all intents and purposes like a digital finite impulse response (FIR) filter.

Automotive Ethernet Compliance: Tests in Detail (Part IV)

Figure 1: The specified pass/fail mask for the
transmitter power spectral density test

We've been making our way through a detailed accounting of the compliance tests for Automotive Ethernet, and in our last post, we covered the distortion test. Now we'll wrap up the tour of the compliance test suite with the test of transmitter power spectral density.