Delay Lines

Delay lines are used to insert a very precise delay into the path of a signal.  A wide variety of delay lines are available.  Some produce a fixed delay, often with multiple tap points, while others produce a delay that may be adjusted by an analog voltage or digital control word.  Adjustable delay lines are a critical component of certain clock synchronization circuits such as a delay locked loop (DLL) or a synchronous mirror delay (SMD).  The performance of an adjustable delay line is usually defined by linearity, which describes how precisely the delay tracks the control signal.