I want to make one circuit in which i need to vary the frequency with voltage and also have to produce 90 degree phase shifted same square pulse.
That phase shifted pulse must also change it's frequency with first wave's frequency.
Not getting how to do exactly.
Thanks

 

Hi,
What you are describing sounds like a square wave quadrature generator.???
Look at this link, it may do what you are asking.
What frequency range and pulse level voltages are required.?

http://forum.allaboutcircuits.com/b...-gen-2-phase-non-overlapping-clock.654/unread

http://forum.allaboutcircuits.com/attachments/quadscope1-gif.72766/

E

 

Frequency range 1-10KHz and voltage level 0 - 15V
Thanks

 

If the linked project meets your requirement, it would be easy to raise the 5V voltage level output from the PIC to 15V by using a couple of general purpose transistors.
[you would obviously require a 15V power supply]

 

You start by generating a double-frequency 50% duty-cycle square-wave.
Have one toggle flip-flip trigger off the rising edge.
Have a second toggle flip-flop trigger off the trailing edge.
The output from the two flip-flops is two signals at the desired frequency with a 90° shift between them.

 

Thank you very much for your concern
It will be better if that circuit will not based on any micro-controller and will consist of normal opams, transistors and some ICs.

 

In case of using Flipflops, I will not need any micro controller for any other thing right ?

 

In case of using Flipflops, I will not need any micro controller for any other thing right ?

Correct. You just need a square-wave generator, flip-flops, and an inverting gate to invert the clock to the second FF.

 

i need to vary the frequency with voltage

Do you mean a voltage controlled pulse generator.?