i dont understand your problem clear. for a digital signal, if the delay is interge times of the orignal signal, for example, y(n), the to get y(n-2), only add two zeros before the seq. of y(n). if the delay is fractional, we can use the fractional filter, the lagrange interpolator is a simple one. if the bandwidth is constrained, such interpolators can be found in the tranditional book or paper. for the all-pass filter with only an expected group delay, it seems harder. for a continuous signal, you can add a delay in the time index.
your signal is an fm signal whose spectrum can be cal or sim by matlab, so you can choose the fitted filter.

hello everyone.. im stephanie a graduating student..and im doing a
>thesis about echo cancellation in communication by a neural network
>using the LMS algorithm...i just want to ask help from you guys about
>how to delay a voice signal???how to delay this signal..
>
>s=(1+0.2*sin(2*pi*fa*t)).*sin(2*pi*f*(1+0.02*cos(2*pi*fm*t)).*t); and
>then may i ask also an example of the matlab program for this
>