Terminator3
Advanced Member level 3
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I came across this page https://www.radiowave.co.uk/007.jpg and found interesting looking microstrip design. At the top of the image we can see LMX2325 that maybe used as prescaler (coupling to Fin pin), and two mixing diodes. But this thing does not look like balanced mixer. Why using two diode pair in such configuration? I can't understeand where RF comes from. Bottom of the image is oscillator (maybe) with quarterwave finger with vias to GND and similar quarterwave finger filter to provide LO to mixer. This receiver uses nice substrate, so i am almost sure it is microstrip parallel feedback. Although other stubs pretty confusing, especially gold-colored screw (bottom of the image). If anyone can explain where RF coming from in this mixer it would be very nice.