请教各位高速信号的Lumps是什么意思，如何翻译？

今天看原版的《高速数字设计》，就算霍华德写的那本黑宝书，第二章61页提到“if the frequency response of a pathway is not flat up to Fknee, signals received at the far end of the pathway may have impaired rise times, lumps, overshoot, or ringing”,其中提到的lumps是什么意思，如何翻译？谢谢各位。