What occurs when an excessive amount of signal energy reaches the mixer circuit?

A mixer relies on a specific amount of non-linearity to properly produce the desired sum and difference frequencies. If the incoming signal energy is too high, it overdrives the mixer, pushing the component into deeper non-linearity or saturation. This excessive non-linearity generates high-order harmonics and unintended mixing products, commonly referred to as spurious signals or 'spurs.' These spurs can cause significant interference or create false signals in a receiver. The circuit does not automatically limit the signal cleanly; instead, it distorts it, creating these unwanted spurious emissions.