IC to Detct Phase Difference

Look at them on a 'scope!

Sorry...miss-read the Q....

Thought it was 'how do I ...'etc.

Whoops.

Sorry...no usefull answer.

This is done in phase locked loops, quite commonly. Look up the data for 4046 or 4064 CMOS chip. That chip incorporates two different phase detectors if my memory serves me well.

Greg

The easiest methods are to use an exclusive-or (or nor) gate and low-pass filter the result (this, for signals of 50% duty factor).

The other is to, as mentioned earlier, the phase detector of a CD4046 PLL--a very commonly available circuit. They contain both an edge detector for which the duty factor of the signals do not matter, and an exclusive-or.

The chips are made on the -B family which can work at up to 15v supply, and HC, which works on a maximum 6 volt supply.

Do you need linearity over a limited range - if so, any sort of multiplying mixer (including the XOR suggestion) followed by a smoothing capacitor) is fine. If you need a monotonic output, you'll need a phase-frequency detector arrangement such as is provided in many phase-lock-loop chips - but be aware that this can have discontinuities in the response around zero phase - and of course limits at about +/-180-degrees (depending on type).

If you want a larger range, it's probably easiest to divide both frequencies by two (or more) before detecting the phase.

I think there can`t be given a general recommendation - a qualified answer requires some more qualified specs ("kind of signal" and others) to get an optimized solution:

1. analog or digital ?
2. Amplitude-range ?
3. Frequency-range ?
4. Flexibility of Design ?
5. Cost-sensitive ?
6. Volume-production or home-brewed single piece ?
7. Resolution and accuracy ?

For digital signals with lower frequencies you can either use "ready" chips out of the well known 4000- or 74xx-series of digital logic or you can build a pll using the timer "555".

Another possibility is time- and period-measurement with a low cost CPU where you can display your result directly in degrees.

Hi frequency applications require special ICs, in this case you could have a look at Analog Devices.

Regards Uwe