That’s the question that will trigger your amygdala’s fight or flight response as you encounter the many annoyances that PAM4 brings to your world. Since you’re in a lab rather than a jungle, that fight or flight response might translate into sarcastic cracks like: “Right, that higher BER requirement makes it all so much easier—not.” “Good old NRZ, those were some fine bits. Remind me why I asked for this?” And, “dear NRZ, I never knew how much I loved you until I lost you.”
