Phase Detection

[D101]

Hi

I have a 5v sine wave the frequency can be varied between 20kHz and 130kHz I need to detect zero crossing and 90 degree's
Can anyone help
Many thanks
David

 

[230842]

Zero crossing detection is possible using a voltage comparator whith low offset characteristics loaded in the output whith a C-R series with a time constant lower than 1 microsecond (1 nF + 470 ohms, for instance)
You can get a reliable and simple 90 degree's crossig detection by mean of an integrating device previous to a zero detector. Integrator can be performed through the voltage of a capacitor connected in series to a resistor, an both to the 5 volts source (100 nF + 4.7 kohms, f.i.) Julian

 

[nbucska]

It is more usual to use a differentiator. (R to GND and series C)

Other : Delay line differentiator : Compare original with delayed signal.

Both usually qualified by level detectors.

More accurate : Phase lock 2,4, etc. times Fr. loop to 0-crossing, divide and qualify with level detectors.

How much accuracy needed? Amplitude ? <nbucska@pcperipherals.com>

 

[mustafagerz]

u can use eather comparator or some ICs. There are some spetial ICs for zero cross detecton. and These ICs possibly gives you better solutions...