By the late 1950s, for instance, the holdover designs of vacuum-tube TV sets forced new transistor-based models to receive only VHF signals until engineers could revamp the sets some years afterward.

• 举例来说，由于1950年代末，真空管电视机的设计过于老旧，新的电晶体机种被迫只能接收VHF信号，过了好多年，工程师才得以大幅修改电视机。