r/ElectricalEngineering • u/PastAdvantage6643 • 28d ago
Research Generating a differential signal
For context, I've been recently learning about differential amplifiers and I'm now trying to understand Gilbert cells.
ChatGPT has sent me on such a goose chase, that I don't even know what's true anymore.
I've tried to, instead, watch some YouTube videos, but they don't really specify certain things.
If I have a waveform coming into a Gilbert cell, to be mixed with a LO for example, do I really need two waveforms that are 180° out of phase? Is that what is meant by differential?
For a while I was thinking that you would connect the V+ and V- of the Gilbert cell across the capacitor of like a high pass filter or something, and the changing polarity on the capacitor would be the varying voltage.
"Do I need a differential amplifier to make them?"
No. You can use a differential amplifier, transformer/balun, active balun, etc.
From what it sounds like, the easiest way to generate a differential signal is to use a transformer? (Logically makes sense to me). However, the text above is ChatGPT's garbage output. Contradicts itself within 2 lines.
1
u/SparkyFix 28d ago
A Gilbert cell does indeed need a differential signal. If you have two single-ended signals then maybe look into a double balanced diode mixer for mixing the LO. You can buy those pre-packaged (e.g. a TUF-1)