Hardware interview practice
Compare TX Emphasis, CTLE, and DFE
A lossy serial channel attenuates high-frequency content and creates post-cursor intersymbol interference. The link can use transmitter FIR emphasis and receiver CTLE/DFE. Which comparison is correct?
Choose one
Answer choices
- A. TX emphasis pre-shapes transitions before the channel; CTLE boosts high frequencies but also boosts high-frequency noise; DFE subtracts estimated post-cursor ISI from prior decisions and can propagate errors when a decision is wrong.
- B. TX emphasis operates only after the receiver slicer, while CTLE changes transmitted symbol amplitudes at the source.
- C. Pre-emphasis, de-emphasis, CTLE, and DFE are interchangeable names for identical circuitry with no adaptation or power tradeoffs.
- D. DFE is a purely linear analog filter that boosts all channel noise by the same amount as CTLE and never uses prior decisions.