Cross talk & Image frequency
Cross talk is -
a) The disturbance caused in the nearby channel or circuit due to transmitted signal
b) Adjacent frequency rejection
c) Generation of closely lying side bands
d) None of the above
Correct Answer: a.) The disturbance caused in the nearby channel or circuit due to transmitted signal
Cross talk is the disturbance caused in the nearby channel or circuit due to transmitted signal. Cross talk is usually caused by undesired coupling of capacitors or inductors from one channel to another. Electromagnetic interference (EMI) causes cross talk in the circuits or the channels. In crosstalk, the signals traveling closer to each other interfere with each other and cause disturbance in the signal.
In terms of signal frequency (fs) and intermediate frequency (fi), the image frequency is given by
a) fs + fi
b) fs + 2fi
c) 2fs + fi
d) 2( fs + fi)
Correct Answer: b.) fs + 2fi
The image frequency is defined as the signal frequency added to twice the value of intermediate frequency. It is the undesirable frequency generated at the receiver which also gets amplified with the message signal. The image frequency causes interference and therefore two or more stations or sources may be received simultaneously at the receiver output.