Almost all (in fact, all of the many that I've used) ASK RF receivers have a dataslicer just before the digital output. The dataslicer uses a comparator (as I explain at http://davehouston.org/RFTipsTricks.htm). Adding another comparator might be useful for educational purposes but is of little practical value (IMO). In this case, the only output from the receiver is digital so the noise pulses will have the same amplitude as the data and the duration of the noise pulses are likely to be nearly the same as the bit period. What kind of comparator circuit are you planning?

It is far simpler to use a relatively wide sync pulse followed by the data. The receiver can look for the sync pulse and only after receiving it, look for the data. The data can use almost any protocol desired, including RS232 with or without manchester coding. The single, wide sync pulse works much better than multiple $55 sync bytes. I also recommend sending 3 or more copies of each packet, including the wide sync pulse.