Question
What combination of a mixer’s Local Oscillator (LO) and RF input frequencies is found in the output?
Answer Options
- A) The ratio
- B) The average
- C) The sum and difference
- D) The arithmetic product
Correct Answer: C
Explanation
A mixer is a non-linear circuit that performs heterodyning by combining two input frequencies: the Radio Frequency (RF) signal and the Local Oscillator (LO) signal. Due to the non-linear multiplication of the two signals, new frequencies are created at the mixer’s output.
The output frequencies include the two original frequencies and the two key frequencies of interest: the sum and difference of the two input frequencies (F_{\text{RF}} + F_{\text{LO}} and F_{\text{RF}} - F_{\text{LO}}). These sum and difference frequencies are what are used as the Intermediate Frequency (IF) in receiver design.
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