help! about the analog phase detector phase gain

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dushan1

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+dbm +phase +detector +gain

I design a 10ghz frequency synthesizers with the skyworksinc spd spd1101-111,when i design the loop filter, i find i can't know the phase gain. anybody can help me ,thanks a lot.
 

how to find phase detector gain

The best thing to do is to test it. Send in a fixed frequency RF signal, say 1 GHz at 0 dBm. Then send in a drive LO signal at a slightly different frequency, like 1.01 GHz (if using subharmonic drive, use something like 101 MHz). Then look at the beat note peak to peak voltage coming out of the PD. That beat note peak to peak voltage is the voltage you get for +/-π degrees. So that is your PD constant.
You need the beat note frequency to be below any R-C lowpass filtering corner frequency you designed.

My guess for a 0 dBm input, is that you will get +/- 0.2 volts, so your PD constant will be around 0.2/π [volts per radian]



Rich
www.MaguffinMicrowave.com
 

thanks for you answer. but the acqusition capability of the spd is not 2pi. why we
divide the beat voltage by 2pi?
 

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