Difference between unbalanced, single and double balanced mixers

In wireless communication mixers/modulators are used to convert low frequency information signal into higher frequency carrier signal. There are many methods of constructing a mixer/modulator. Some mixer/modulator are constructed using diodes and other using BJT or FET transistors(JFET, MOSFET). One of the important classification of mixer/modulator is whether it unbalanced mixers, single balanced mixers or double balanced mixers. The difference between these mixers type is based on the output signal content.

Unbalanced Mixer/Modulator
If the output signal contains both the modulating signal and carrier signal along with the desired modulated signal then it is called unbalanced mixer. An example of such unbalanced mixer is Single Diode Modulator Circuit.

Single Balanced Mixer/Modulator
If the output signal contains either the modulating signal or the carrier signal along with desired modulated signal and the other is suppressed then such mixer/modulator is called single balanced mixer. An example of single balanced mixer is Two Diode Single Balanced Mixer.

Double Balanced Mixer/Modulator
A double balanced mixer/modulator is one that suppresses both the modulating signal and carrier signal at the output. An example fo double balanced mixer is Double Balanced Diode Ring Mixer.