What are the principal frequencies that appear at the output of a mixer?
Two and four times the input frequency
The square root of the product of input frequencies
The two input frequencies along with their sum and difference frequencies✓Correct answer
1.414 and 0.707 times the input frequency
Explanation
A mixer multiplies two signals, and multiplication of two sine waves produces their sum and difference frequencies. In a practical mixer some of both input frequencies also appears at the output, so a filter selects the wanted product.