yes this the same circuit from same source from I linked it here.
Your link only took me to the home page.
so you are suggesting I should use 393???
Yes, if you need it to go to 5 volts and operate at a fairly high frequency. Or use a much faster rail to rail op amp.
there is something that i want to asked >> how should I increase the input frequency. because there is only 150KHz range( in the above circuit) ...
If tou want the frequency higher you need a faster comparator than the 393. It will probably run higher if your signal will always be a square wave like you get from the 555, but if you plan on a sine wave it will need to be faster since the comparator only turns on right at the peak.