why we don't consider about group delay in analog design?

[gunner_fan]

In RF design, there is a group delay specification. If delay is different in different frequency component, a serious wave distortion named as Phase Distortion comes out.
In analog design, such distortion exists as well. But it is neglected as i know. At least, it is not considered in Gray,Allen and Razavie's books.

why? why we don't consider about such distortion in analog design?
i hope somebody give me some advice.

Thanks very much!

 

[rickleicn]

hi,if the model of analog system is finite impulse response type,then the phase-response of this analog system is linear,as a result,the wave is just delayed and not distorted.