popular slang for a homodyne with an extremely low pass filter, which making it very narrow band. Usually includes a frequency mixer, and not to be confused with bandpass filter.
"That lock-in is essentially shot-noise limited."
"I'm using the reference from that lock-in because I don't have a function generator."
"I'm using the reference from that lock-in because I don't have a function generator."
by novakyu November 25, 2007