An analog delay line is a network of electrical components connected in series; where each individual element creates a time difference or phase change between its input signal and its output signal. An example is a bucket-brigade device.
It is a variant of a delay line

Delay line

Delay line may refer to:* Propagation delay, the length of time taken for something to reach its destination* Analog delay line, used to delay a signal...

and is capable of handling signals whose amplitude varies continuously.