Need suggest on phase detector

Hi, everyone

I am an undergraduate student in microwave engineering. and i am hunting for a kind of phase detector to compare the phase difference of two channel signals.and Phase resolution of the phase detector
Can reach 0.022°，200MHz. Could u please give me some suggestions? which device can meet those demand?


Thanks a lot!

regards

Well, many analog phase detectors have that "resolution", because they are....analog. The problem is that they have built in errors. A simple microwave mixer with a DC coupled IF port will give you a good phase detector output over a +/- 45 degree range. There will be some built in offset DC voltage (that will change vs power input) that you have to calibrate out, so the "accuracy" is not as good as you want.

There are I/Q mixers that will put out two signals that, combined, will give you the phase difference over the full 360 degree range. Those mixers tend to have DC offsets on both I/Q outputs, have difference "gains" for the two outputs, and might have some non-monotonic effects due to rf reflections inside of the device. These all effect the accuracy.

There are digital phase dectors that detect over a +/-360 degree range. They are more linear, but might have a dead zone somewhere in the range where the two input signals are almost the same phase.
Products - Hittite Microwave Corporation

IF you want to eliminate the errors, you will have to have some sort of calibration routine.

You could take any of the above schemes, use frequency multipliers on both signals first, and then do the phase detection. For example, use a X8 frequency multipliers on both signals, and then do the phase detection. You would have a smaller phase detection range, though. But your resolution would look like it was 8 times greater.

If you want much fewer errors, you will want to digitally sample the signal and do the phase detection in a DSP circuit. If it is a limited bandwidth input, you can downconvert the two signals with a common LO, and digitally sample it at a lower rate.

Hi,biff44
thank u very much!

thank u for your good suggestion.
I read a paper about SAR rencently, in this paper, the author mentioned, "The phase detector had an output phase resolution of 0.022 ", so i am interested in it , Which type of phase detector can realize what kind of phase accuracy ? How to do it?

That paper is followed:

I guess the 0.022 is realized in digital domain. Anyway it is difficult.

digital domain? I do not understand, can u say it in detail?

thanks!

digital domain is used ADC for both I and Q channel, as I think.
Then the processor use FFT/IFFT to get the phase information from these sampling data.

Dranetz 305C: "0.01 degree resolution", whatever that means:

Dranetz 305C Phase Gain Meter - Advanced Test Equipment Rentals

thanks, but the this equipment is too large, and can u recommend several MMIC chips? And its phase error resolution and working frequency can meet the demand. i read the Products - Hittite Microwave Corporation , it seems that its resolution at 200MHz could not meet the requirements for the project .

thank u very much!

best regards!

Analog Devices AD8302 maybe?

Keith

Before asking for more detailed suggestions, you should clarify your requirements. You didn't tell yet, if you're intending the high resolution for a restricted phase difference or over a full 0-360° range. There's also a large difference between resolution and accuracy.

Keith and Fvm,

Thank u for all!

Yes, i wann to compare the phase defference between signals in two defferent channel. and i hope there are a high resolution of 0.022° at 200MHz, in my project, the requirements is the same with that which is mentioned in the paper above, So i wann to test and verify what the author mentioned in his paper. He only said in the paper that "The phase detector had an outpout phase resolution of 0.022 and ....", and the type of the phase detector was not mentioned. I am looking for the phase detector which was applied in the author's project.

Thank u for all. and i hope all that give me some advice about the phase detector, type in better!

John

I have used the AD8302 in a laser rangefinder at 300MHz, so it is worth looking at.

Keith.

thanks , i 'll try it !

John