simulation pwm ads

Hello guys,
Could any please help me to build a simple macro model for a PWM converter on ADS?
What I want is to convert a sine wave to PWM signal for system level simulation purposes.
Thanks anyway,
WM3

I don't know any PWM model available but you can create a PWM with a comparator and a ramp signal.
by comparing this 2 inputs you get a PWM signal.