continuous square wave generation from pulses required !!!

[Ow@i$]

Hi guys,
Referring to following simulation result:



I want a continuous square wave at output rather than several pulses ( Shown in green ),
as long as input ( the red signal ) is high above certain level...!!!

what should I do ?? like envelop detection or can i convert those pulses into a continuous square wave???

any help appreciated

 

[FvM]

A retriggerable monoflop can do it.

 

[rohitkhanna]

Its not really clear WHY you would need such perfect square waves - and i assume you mean a 50% duty cycle. But lets say it's absolutely necessary.

Here's an idea --

After your comparator at YOUR measurement level, put an RC on the output whose time-constant is just greater than 2/freq. Put in a trimpot for the 'R' to adjust. I.e. The output should stay high as long as your signal is greater than the threshold, but go low within 1 cycle if its not. Follow the RC with a schmitt - for cleaner signal switching.
Something like a retrigerable monoflop without the actual chip.

The result should be what you need.

 

[Ow@i$]

Thank you all for help... I actually tried an envelop detector (Diode, Capacitor, and a Resistor ) and it worked according to the need !!1 here is what is got !!!



and by the way this thing worked practically too!!