Hello Everyone. I'm new to these forums so please forgive me if this has already been discussed.
My senior design project for my Electrical Engineering degree is to build a discrete PLL that locks between 1kHz and 100kHz.
Everything must be made using discrete parts (no ICs, no op-amps). I also am not allowed to use a phase-frequency-detector (PFD) for the detection stage of the system.
Currently I am trying to tackle how to build the VCO. I have already thoroughly tested ring oscillators in the lab and have ruled them out because they oscillate too quickly (MHz range) and their peak-to-peak voltage changes with the control voltage which I can't have.
Does anyone have an idea of how to design a low frequency VCO which has a constant VPP of 5V? Ideally the output waveform is a square wave, but if not that is ok I can build a schmitt trigger to take care of that.
Any help is greatly appreciated. Thanks.
My senior design project for my Electrical Engineering degree is to build a discrete PLL that locks between 1kHz and 100kHz.
Everything must be made using discrete parts (no ICs, no op-amps). I also am not allowed to use a phase-frequency-detector (PFD) for the detection stage of the system.
Currently I am trying to tackle how to build the VCO. I have already thoroughly tested ring oscillators in the lab and have ruled them out because they oscillate too quickly (MHz range) and their peak-to-peak voltage changes with the control voltage which I can't have.
Does anyone have an idea of how to design a low frequency VCO which has a constant VPP of 5V? Ideally the output waveform is a square wave, but if not that is ok I can build a schmitt trigger to take care of that.
Any help is greatly appreciated. Thanks.