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LTC5549/5548 isolation of 3*LO (with doubler enabled)?

Question asked by rfwerk on Jun 23, 2018

I am investigating using these mixers for use with a 3.5GHz LO and the doubler leading to mixing with 7GHz.

 

When I examine a sweep IF from 0-3GHz I observe not only 2*LO+IF (7-10GHz) but also 3*LO-IF (10.5-7.5GHz).

The sweep is recorded here: https://drive.google.com/file/d/1UZsZ3OJ2wlv2pM1S-OPAInMlDN67kI3R/view

It looks like the mixing result of 3*LO-IF is only ~17dB lower than 2*LO+IF.

 

Is this expected?

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