Receivers

Explanation of question 8

A superheterodyne receiver having an IF of 9MHz is tuned to a frequency of 14.3MHz. The local oscillator frequency is greater than the signal frequency. The frequency of the local oscillator will be

1. 23.3MHz
2. 11.65MHz
3. 5.3MHz
4. 3.7MHz

The answer is :- 1

The local oscillator frequency can be either 23.3 MHz (14.3 MHz + 9 MHz) or 5.3 MHz (14.3 MHz - 9 MHz). But the local oscillator frequency is greater than the signal frequency, i.e. 23.3 MHz.