What principal frequencies are produced at the output of a mixer circuit?

A mixer circuit is designed to combine two input signals to produce an output that contains new frequencies, specifically the sum and the difference of the original frequencies. When two signals at different frequencies are mixed, the mixer generates two new frequencies: one that is the sum of the two original frequencies and another that is the difference between those frequencies. This property is crucial in various applications, such as in radio frequency (RF) communications, where it is used in modulation and demodulation processes.

The original frequencies themselves are often still present in varying amounts due to the nature of the mixing process, but the key output of interest are the resulting sum and difference frequencies. Therefore, understanding this fundamental behavior of mixer circuits is essential for anyone working with RF technology or signal processing.