90 degree
90 degree
(OP)
Hi,
I have an incoming frequency that is set to 60 Hz. I will call this my sync signal. I also have a 60 Hz signal that varies in phase and amplitude, which I will call my modulated signal. This signal is from the same source as my sync signal. Although the sync signal is not modulated.
I need to be able to demodulate the modulated signal. I already have an in phase component which is my sync signal. I need to be able to generate a signal that is a square or sine wave that is 90 degree out of phase from my sync signal.
If it helps to solve the problem, I can also change the phase of my sync signal. What is important is that I have two signals that have a 90-degree phase relationship and are phase locked to the sync signal. I will use these two signals to demodulate my modulated signal.
In addition, I would like to have this circuit work if I change my frequency from 60 Hz to 50 Hz.
Thank you for any help you can give me.
I have an incoming frequency that is set to 60 Hz. I will call this my sync signal. I also have a 60 Hz signal that varies in phase and amplitude, which I will call my modulated signal. This signal is from the same source as my sync signal. Although the sync signal is not modulated.
I need to be able to demodulate the modulated signal. I already have an in phase component which is my sync signal. I need to be able to generate a signal that is a square or sine wave that is 90 degree out of phase from my sync signal.
If it helps to solve the problem, I can also change the phase of my sync signal. What is important is that I have two signals that have a 90-degree phase relationship and are phase locked to the sync signal. I will use these two signals to demodulate my modulated signal.
In addition, I would like to have this circuit work if I change my frequency from 60 Hz to 50 Hz.
Thank you for any help you can give me.





RE: 90 degree
RE: 90 degree
I am not sure how to apply the quadrature encoder to my problem. I don't generate the 60 Hz signal. I just need to synchronize to it. Then generate both in phase and quadrature signals that are synchronized to the incoming signal.
Thanks,
RE: 90 degree
RE: 90 degree
with AC hysteresys. Phaselock to it a 120Hz PLL and
reclock with it the sqw twice.
<nbucska@pcperipherals.com>
RE: 90 degree
try a RC filter with a cutoff of 5 hz. This
will give a phase shift of around 85 deg.
Then feed this to a AC coupled comparator to
recover the full strengh phase shifted signal.
Otherwise nbucska has a good solution.
Generate a 120 Hz squarewave with a voltage controled
oscillator then divide it by two and feed a
phase lock loop to sink it with the 60 hz reference.
And cbarn24050 is correct that it is a simple program
for a small CPU. If your circuit allready has a CPU
this is the way.
Rodar
RE: 90 degree
Thank you all for your suggestions. I will need a 90 +/- 1 degree quadrature signal. I do not have a CPU in my circuit. I must also admit that I am not sure how to use a CPU to accomplish a 90 degree phase from my sync signal.
I used the phase locked loop concept, I think my 90 degree signal was noisy even though it was phase locked and looked like it should work. I believe this because when I used an RC filter to get close to my 90 degree phase difference, I was able to demodulate my modulated signal without noise showing up in it. However I did not have the 90 +/- 1 degree accuracy I needed. When I used the phase locked loop concept, I had a lot of noise in my demodulated signal that I did not see when I used the RC filter. I know I need to do some more work on this. I am not sure why I am getting this noise in my phase lock loop circuit. Any additional suggestions are appreciated. Thanks again to all of you who offered suggestions.
sparkyyyyy
RE: 90 degree
RE: 90 degree
RE: 90 degree
This product will go into production.
RE: 90 degree
RE: 90 degree
Thank you for your input. I will try to see if I can find someone to program a PIC for me. I have not done this myself. Thanks again.
RE: 90 degree
RE: 90 degree
RE: 90 degree
RE: 90 degree