Construct the schematic for the CMOS comparator. Include in your schematic an op amp that is configured as a non-inverting amplifier that: has a resistor (R2) connected between the op amp's positive input and the op amp's output has a resistor (R1) with one end connected to the positive input of the op amp and the other end connected to the input signal source your comparing. Also include a positive reference voltage source (that your comparing the input signal to) that is connected to the negative input of the op amp.
Define the maximum and minimum voltage levels of the input signal that will drive the input of your op amp. For this example, assume that a maximum voltage level of 6 Volts and a minimum voltage -6 Volts.
Establish a lower threshold voltage for the comparator for the input signal to be below to switch the output of the comparator to ground (0 Volts). For this example use 4 Volts for the positive threshold votlage. Establish a upper thresshold votlage for the comparator to produce an output voltage equal to the supply voltage. For this example use -4 Votls for the lower threshold voltage.
Divide the positive threshold voltage (4 V) by the minimum voltage level (6 V) to obtain the ratio of the feedback resistors (R1/R2) as 2/3. Multiply this ratio by 1000 and use a value of 2000 ohms for R1 (the input signal resistor) and value of 3000 ohms for R2(the feedback resistor).
Simulate your circuit on a SPICE simulator to verify that your op amp switches positive and negative.