Re: AD8302: What is the maximum allowable difference in signal amplitudes in order to obtain a phase measurement?

Hi Joel,

Thanks for your reply. I just have a quick follow up question regarding 8302 I saw in the FAQ section. It is pasted below. My question is: What is the output phase voltage of AD8302 when one of the input signal is smaller than -60dBm? Will the phase output voltage still be around 0.9V or will it just oscillate like crazy between 0 to 1.8V?

thanks

Andy

Q.

What is the output voltage of the AD8302 gain/phase detector when there are no signals present on the inputs?

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A.

With no input signal, the AD8302 compares the noise on the two inputs.  The noise on the input is generally the same level, so the magnitude output is approximately 0.9V.  Due to an internal 90 deg phase shift, the Phase output is also approximately 0.9V.