These FETs are not really 'biased' in the normal sense anyways because the drains are open circuit for DC so there is no bias current flowing. What you are doing is raising and lowering the potential of the whole channel. Variation in the device fabrication processes result in device to device variance in transconductance so perhaps in this strange circuit balance is more important??
On 28/02/2014 4:58 PM, Tayloe, Dan (NSN - US/Tempe) wrote:
That might change the balance of the mixer, but does not change the bias on each gate. - Dan -----Original Message----- From: minima-bounce@xxxxxxxxxxxxx [mailto:minima-bounce@xxxxxxxxxxxxx] On Behalf Of ext Sandeep Lohia Sent: Friday, February 28, 2014 2:56 PM To: minima@xxxxxxxxxxxxx Subject: [minima] Re: KISS Mixer Musings http://4.bp.blogspot.com/-fIABMtTpyUE/Ut9yfPotc0I/AAAAAAAAAUQ/IG6TveVonrw/s1600/under+R&D.jpg NOTE : not yet tested live...IF you have two separate bias pots, You could bias the two JFETs with separate pots and adjust for similar drain Just thinking about this. I remember that the transconductance of JFETS varies quite a bit so the fact that the signals are not symetrical might be due to an imbalance in the device characteristics?Please take a look at the link and then any volunteers who can try and explain this to me most welcome!
