Function of RF mixer & Selectivity of a receiver
Function of RF mixer is
a.) Addition of two signals
b.) Multiplication of two signals
c.) Rejection of noise
d.) None of the above
Correct Answer: b) Multiplication of two signals
Explanation:
RF mixer translates the frequencies of the two incoming signals from one band to another by multiplying them. When the two incoming signals are mixed, the new frequencies obtained are the sum and difference of incoming signal frequencies .i.e., if the two input signal frequencies are f1 and f2, then the output of the mixer will have signals at frequencies (f1+f2) and (f1-f2).
If a receiver has poor capacity of blocking adjacent channel interference then the receiver has
a.) Poor selectivity
b.) Poor Signal to noise ratio
c.) Poor sensitivity
d.) None of the above
Correct Answer: a) Poor selectivity
Explanation:
Frequency selectivity means to separate out closely lying components of frequency. If the receiver has poor selectivity, it has poor capacity of blocking adjacent channel interference.
