Topic: Communications
If two tones f_1 and f_2 are amplified by a non-linear amplifier, which frequency components would be present in output?
- A. f_1, f_2
- B. f_1, f_2, f_1 + f_2, f_1 - f_2
- C. f_1 + f_2, f_1 - f_2
- D. nf_1 ± mf_2, where n and m are integers
Answer: D. nf_1 ± mf_2, where n and m are integers
Explanation: As input frequencies f_1 and f_2 are passed through non-linear filter so output signal is of the form V_o = (A_1 cos 2π f_1 t + A_2 cos 2π f_2 t). So, there will be multiple harmonics of frequencies depending on value of β. ∴ Output frequency = nf_1 ± mf_2 where n and m are integers.