Answer to Question #110649 in Electric Circuits for HH

Question

In case of a receiver explain the following terms with the help of graphs: (i) sensitivity, (ii) half power point, (iii) linearity and (iv) fidelity. What should be their ideal behaviour/value?

Answer 1

i)The receiver sensitivity level tells us the weakest signal that a receiver will be able to identify and process. It can be improved by reducing the noise level and bandwidth of the receiver. A typical range for receiver sensitivity for RF modules is below -50 to -100 dBm.

the input signal has some frequency offset and if the receiver does not use a frequency offset correction mechanism, the sensitivity level will be degraded

ii) The half-power bandwidth is the point at which the output power has dropped to half of its peak value; that is, at a level of approximately -3 dB. In filters, optical filters, electronic amplifiers, the half-power point is a commonly used definition for the cutoff frequency.

iii) The linearity of the receiver is best summarized in the concept of Equivalent Input Intercept Point of the receiver . This parameter takes into consideration the effect of non-linearity of every stage in the receiver, including amplifiers, mixers, and filters.

iv) The steepness of the response curve at the tuned frequency indicates the selectivity of the receiver. Fidelity The fidelity of a receiver is its ability to accurately reproduce, in its output, the signal that appears at its input.