Nothing has been said about a frequency range in the original post. Thus I would suggest an active all-pass circuit. It can be easily adjusted to achieve 90° for a given frequency by varying a single resistor. https://en.wikipedia.org/wiki/All-pass_filterA 741 cannot do this alone. It can invert which is almost the same as 180 shift but not any other angle. The trouble with phase shifting is the amount of shift depends on frequency so wideband circuts are difficult to build.
The "polyphase" network shown earlier is probably the best you will find. You can use a 741 to produce the anti-phase input the network requires and to buffer the outputs.
It's all in the wikipedia link.general circuit design with there equation to complete my design ,,,,that's what i need ????
The phase shift in the Wikipedia circuit is +90 degrees, not -90 degrees, at the RC corner frequency. If you need the opposite phase shift, just interchange R and C.firstly thanks for your replay,,,,,,,, but in the wikipedia link the phase shift circuit was -90 degrees phase shift at output as in attached picture ,,,,,,,,, and this mean i need second phase shift ???!!! ,,,,,,,,,,,, I need to enter sine wave to give me at output cosine wave , thanks .View attachment 81460
firstly thanks for your replay,,,,,,,, but in the wikipedia link the phase shift circuit was -90 degrees phase shift at output as in attached picture ,,,,,,,,, and this mean i need second phase shift ???!!! ,,,,,,,,,,,, I need to enter sine wave to give me at output cosine wave , thanks .View attachment 81460
The output will need to be amplified.
The phase shift in the Wikipedia circuit is +90 degrees, not -90 degrees, at the RC corner frequency. If you need the opposite phase shift, just interchange R and C.
Why not simply use an inverting Miller integrator? I think it will introduce a phase error that is considerably lower if compared with all the other methods (due to parts tolerances).
Integrator change the amplitude of input signal according to frequency ,,,,,,,,,,,,, Thanks for your replay
Don't know what you are talking about. What is "incorrect result"? What would be the correct result?I simulated it in many program and gives the same result -90 degree phase shift , and if i interchanged R & C gives incorrect result ,,,,,,,, thanks for your time
What do you really need? A 90 deg phase shift with a constant amplitude for a certain frequency band ?
Don't know what you are talking about. What is "incorrect result"? What would be the correct result?
yes this which i need A 90 deg phase shift with a constant amplitude for a certain frequency band ,,,,,,,,, thanks
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and the correct result which i need it is A +90 degrees phase shift with a constant amplitude at certain frequency ,,,,,,,,,,, thanks a lot
I wonder how you read a phase shift from a single waveform? You possibly know the input waveform, but we don't.I mean that gives no phase shift as in picture.
In your own interest, you should try to describe your problem without such contradictions.
I wonder how you read a phase shift from a single waveform? You possibly know the input waveform, but we don't.
P.S.: Guessing a bit about the missing information, it seems like the input waveform is a sine with 0 degree phase shift, switched on at t=0, and the output is a cosine. You have been possibly confused by the initial transient and missed to measure the actual phase shift.
As a matter of fact, by exchanging R and C, the discussed allpass circuit covers a full phase range of 0..360 degree. Thus I wonder how you managed not to get the intended phase shift. I guess, either your circuit is wrong or you misunderstood the results.ahha ,,,,, the input wave form is sine wave and I mean the exchange between R and C gives not exactly phase shift which I need
As a matter of fact, by exchanging R and C, the discussed allpass circuit covers a full phase range of 0..360 degree. Thus I wonder how you managed not to get the intended phase shift. I guess, either your circuit is wrong or you misunderstood the results.
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