Question

In a balanced mixer, the output _________

(a) contains equal amount of all input frequencies

(b) does not contain the input frequencies

(c) contains the input frequencies

(d) is a non-linear mixture of input signals

The question was posed to me during an interview.

The origin of the question is Noise in Pulse Modulated System topic in section Phase Locked Loop & Pulse Modulation of Analog Communications

Answer 1

The correct choice is (b) does not contain the input frequencies

Best explanation: Mixer is a device that multiples two signals. In a balanced mixer, the output does not contain the input frequencies. And if it contains the frequency then mixer becomes imbalanced.