Help me choose a low pass filter design

I have to design and implement a pulse width modulated system to control remote a motor.
The specifications are the following
The control signal is a sine wave having amplitude A.
A can have integer values from 0 to 4.
and the frequency is 10Hz.
A triangular wave has a frequency of 1khz.

I use a comparator to get a train of pulses of varying widths. Now I have to design a low pass filter
my questions is
what filter design can I use?
any interesting links on low pass filter design?