Write short note on the following: i. Radio transmitter ii. Radio receiver iv. Automatic gain control v. Automatic frequency response – NABTEB QUESTION

i. Radio Transmitter: is to generate radio-waves for transmission into space

ii. Radio receiver: is a device that picks up electromagnetic waves sent out by a transmitter amplifiers them, detest them, so that they can be hard and amplifiers them to normal listening level, in order ward. A radio receiver: is a device that picks up all electromagnetic wave present to space, it select the
wanted radio wave and reject others, it extract the intelligence contained in the modulated signals and produces an audio frequency output of sufficient power to operate the loud speaker or other receiving device such as (CRT, GSM screen e.t.c)

iii. Selectivity in a record set: The selectivity of a receiver is it’s ability to reject unwanted signals. In order word is the ability of a receiver to separate the signals of the desires station from the signals of the other station?

iv. Automated gain control: AGC is a method of automatically turning the volume to loud when the signal becomes weaker and to soft when the signal becomes stronger. AGC is needed to keep the output of the detector steady since the receiver carriers Varies in strength through fading. It also protect the I.F from overlapping which causes various forms of distortion.

v. Automated frequency control: is used in FM radio. As well as TV receivers, to ensure a stable intermediate frequency.