Mixer Circuit Help

excetara2

Member
2006-06-12 1:03 am
I have a simple RF section where I am trying to mix a 100Khz and a variable signal. Ranging around 98-102Khz. I need to build a mixer to get the difference of these frequencies. I wasn't sure what would be the best design or what to use? I was thinking about using Fets. I am new to this game so don't know a lot. The output will be fed to a low-pass filter to get rid of the addition of the two signals. I couldn't find any simple designs on the boards. Any help would be great.
 

MaxS

Member
2006-03-25 7:02 am
France

unclejed613

Member
2006-12-28 12:19 am
super simple answer: diode ring mixer. 4 schottky diodes and two easy to make toroid transformers. unit has 2 input ports and 1 output port. output port contains sum and difference frequencies, and a simple filter lets you select sum or difference. also known as a double balanced mixer.

a bipolar transistor or jfet would give you a mixer with gain, but requires a bit more finesse to design properly. the diode ring is a wideband design, the transistor mixer usually requires tuned circuits at the inputs and output.