I'm new here so I'm going to make is as simple as it can get.. How can I bias a Gilbert cell with bjt transistors like this one: What methods can I use to bias the transistors? Is there any example schematic where they show how biasing resistance are put and calculated?
I've tried many methods but I got stuck, because I suck at dealing with transistors since uni days.. For instance, I could bias the diff amps with base resistance method, like this one:
but got stuck in biasing tail transistor since it's its collector is linked to the upper diffs emitters rather than +vcc like in this example:
I may have done my research in the wrong way, but I've looked in many articles, files etc even in different languages, but all I can find is basic gilbert cell theory and that's it, I managed to find only one practical example so far.
Please, I'm getting really desperate, I've been stuck with this for a very long time now, the place where I live, electronic devices are really limited, I can't find mixers in any shape or form, IC mixers, or even toroid to make a diode ring mixer since it's simpler. All I have is only 2N2222A transistors that could operate up to 300 MHz, so they're my only way. I appreciate any type of help, advice or information you can give me.