is it possible to create an analog circuit which provides 90 degrees phase shifted signal from input sine signal of 100v amplitude and 100v dc offset, over a frequency range of 10hz - 300hz. I tried using all pass filter of first order for fixed frequency 1khz for trial then moved onto cascaded all pass filters but i am unable to design the circuit to get the intended 90 degrees phase difference

 

You can do it for a fixed frequency. In order to do it at different frequencies, you would have to determine the input frequency and then use a tuneable filter.

Or you can use an MCU to measure the frequency and then apply the shift in a bucket brigade or in software.

 

You can do it for a fixed frequency. In order to do it at different frequencies, you would have to determine the input frequency and then use a tuneable filter.

Or you can use an MCU to measure the frequency and then apply the shift in a bucket brigade or in software.

thank you for your response
Regarding the tunable filter (digital potentiometer) approach, is it practical to design and simulate such a filter in LTspice, or would you recommend using a different software package for this type of design and optimization?

 

Technically you could shift a signal 90° with respect to itself with an integrator but would also have to deal with the output amplitude being frequency dependent. Another way is create two new output signals that are 90° apart with respect to each other over the 10-300Hz range.

As for the 100V AC amplitude and 100V DC offset, cut the DC, attenuate the amplitude to a more practical value, introduce 90° phase shift and after that amplify back to 100V AC and add original DC offset.

 

Is this for a single frequency at a time, or a wide-band signal containing simultaneous multiple frequencies.