In a superheterodyne receiver, when 2 signals at frequencies 550
In a superheterodyne receiver, when 2 signals at frequencies 550 kHz and 1050 kHz are mixed together, new signals are generated at frequencies
A. 550 kHz
B. 1050 kHz
C. 1000 kHz
D. 1600 kHz
Please scroll down to see the correct answer and solution guide.
Right Answer is: D
SOLUTION
The signal that is picked up by the antenna of the superheterodyne receiver is passed to the mixer.
There are three signal ports on the mixer: signal, local oscillator and IF as shown:
The mixer action is to multiply the instantaneous levels of the two signals together. The non-linear action of the mixer generates signals at frequencies equal to the sum and difference of the incoming signals as shown:
Application:
Given f1 = 550 kHz and f2 = 1050 kHz
The new signals are generated at frequencies:
Upper frequency = f1 + f2
Lower frequency = f1 - f2
fupper = 550 + 1050 kHz
fupper = 1600 kHz
flower = |550 - 1050| = 500 kHz
