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Discuss the factors that influence the choice of IF in superheterodyne receivers.
written 6.2 years ago by gravatar for teamques10 teamques10 ★ 64k modified 2.1 years ago by gravatar for DevarenjiniP DevarenjiniP • 3.1k
principles of communication network
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written 2.1 years ago by gravatar for DevarenjiniP DevarenjiniP • 3.1k

CHOICE OF INTERMEDIATE FREQUENCY

  • IMAGE REJECTION RATIO : Pick up due to local oscillator radiation from TV receiver

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  • Easy to separation modulating signal from IF carrier at the demodulator =

    Radio receiver IF frequency 455KHZ and audio frequency 5KHZ , in TV receiver higher modulating frequency 5MHZ and IF frequency 40 MHz

  • Image frequency should not lie in FM band =

    FM band 88MHZ to 110MHz Intermediate frequency 40MHZ ,

    Image frequency lower VHF band 121 to 148MHZ

  • Interface and direct pickup from band assigned for other service = Industry application frequency 21 to 27MHZ and intermediate frequency 40MHZ

  • Gain = Intermediate frequency 40MHZ 625 B signal adopt in India which picture IF 38.9MHZ , sound IF 33.4MHZ USA picture IF 45.75MHZ , sound IF 41.25MHZ
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