- on RF (radio)
- Published in issue 7/2010 on page 40
AM Receiver with Quadrature Mixer
(Summer Circuits 2010 article)
This circuit is for a superheterodyne receiver where the image frequency is suppressed without the use of an input filter. Instead, it uses two NE(SA)612 type mixer ICs that each work 90( out of phase. With a quadrature front-end, the image frequency is rejected and the noise associated with it disappears. In theory, this increases the sensitivity of the receiver by 6 dB.