MC1496
Double Balanced Modulator

A mixer is a nonlinear element that combines two signals. A mixer has three ports: F1 receives low level signal; F2 is high level signal (local oscillator) and F3 is the resultant mixer product.

The output of the mixer contains number of different frequencies that obey the relationship   Where m and n are integers 0, 1, 2, 3,...

There are three types of mixers: single-ended, single balanced and double balanced. Double Balanced Mixer (DBM) suppresses F1 and F2 components of the output signal leaving only the sum and difference frequencies. Double Balanced Mixer provides superior suppression of the local oscillator and RF signals in the output leaving only the sum and difference frequencies. This is known as port to port isolation