"shift my signal by 90 degrees" So, what is your signal? Where does it come from. I just assume it is a digital signal, is it?
And what is the reason you do not want to use a FF.
Thank you, Bob, for your reply!
Correct, It's a digital square wave signal coming out of the comparator and entering into the LO input of the Mixer.
I am avoiding using flip flop because, in my full schematic design, I get half of the frequency at the output of the flip-flop.
I was thinking about shift register but I am not sure how should I use it. Maybe a shift register with the not gate? What do you think could be the best thing i can do about it?
Looking for your reply!
You could try to measure signal high and low time (or frequency and duty cycle) and generate a 90 degrees shifted signal using a PWM.
This could be possible but I would not be flexible if my input frequency would change for some reason.
I thought for a constantly measure of a single cycle input signal and controlling the PWM. Can probably done with a 100kHz signal. What are the precision restrictions you have got? And: What is the lowest frequency to handle?