a Sample and hold circuit model

[Manivannan]

Hi,

i am trying to model a Sample and hold device for a ADC, using
VHDL-AMS on Cadence.I used the Zero Order Hold attribute ('zoh()) to
sample the inputs. The code had no problems running on Mentor Graphics
System Vision, but when i ported the code to Cadence it did not. I
seems that the 'zoh() function is not yet built into Cadence VHDL-AMS
Simulator.
Now my question is that is there any equivalent function for 'zoh() ?

I have posted this query in comp.lang.cad.Cadence , but no reply as of
now!

will be happy if somebody could clear this..

Cheers
Manivannan