What is noise figure? What is indicates?

Ans. The noise figure (F) is defined as the ratio of the signal-to-noise power supplied to the input terminals of a receiver or amplifier to the signal to- noise power supplied to the output or load resistor.

Noise figure (NF) and noise factor (F) are measures of degradation of the signal-to-noise ratio (SNR), caused by components in a signal chain. It is a number by which the performance of an amplifier or a radio receiver can be specified, with lower values indicating better performance.

What are the problem in the recovery of the baseband signal?

Ans. Suppose that the auxiliary signal used for recovery differ in phase from the auxiliary signal used in the initial translation. If this phase angle is ɵ, the recovered waveform will be proportional to m(t) cos ɵ i.e., amplitude attenuates. Suppose that the recovered baseband signal is not precisely at frequency fc but is instead at fc + ∆f then the recovered baseband signal will be proportional to m(t) cos 2 π∆ ft, resulting a signal which will wax and wane and thus the recovery of the message signal won’t be possible. 

Keep the following in mind when dealing with conversion of parameters in two port networks. These are useful tricks to remember when solving questions for GATE EC or GATE EE.

In series type connections, Z parameters get added.

In parallel type connections, Y parameters get added.

In cascaded type connections, ABCD parameters get multiplied.

In series–parallel type connections, h parameters get added.

In parallel–series type connections, g parameters get added.