What degree of selectivity is desirable in...

Question 1 / 27070kjiJDTmyvCADYm4hbugk

Question 1 of 27070kjiJDTmyvCADYm4hbugk

What degree of selectivity is desirable in the IF circuitry of a wideband FM phone receiver?

Question 1 of 27070

What degree of selectivity is desirable in the IF circuitry of a wideband FM phone receiver?

🔍 Key Concepts

• Wideband FM voice signals typically occupy more bandwidth than SSB (single sideband) or CW (Morse) signals • The IF (intermediate frequency) filter bandwidth must be wide enough to pass the whole FM signal but not so wide that it adds extra noise • Compare these values (1 kHz, 2.4 kHz, 4.2 kHz, 15 kHz) with the normal audio and deviation range of wideband FM phone

💭 Think About

• Which of these bandwidths would be far too narrow to pass a normal FM voice signal without severe distortion? • Which bandwidth is closest to the channel spacing and occupied bandwidth commonly used for standard wideband FM voice communication? • How does making the IF filter too wide affect noise and adjacent-channel interference?

✅ Before You Answer

• Eliminate any bandwidths that are clearly narrower than typical FM deviation and audio range • Think about common FM channel spacing used in marine/VHF services and pick the bandwidth that would comfortably fit that signal • Choose the value that balances enough bandwidth for clear audio with not so wide that it increases noise and interference

Question 1 of 27070

What degree of selectivity is desirable in the IF circuitry of a wideband FM phone receiver?

1 kHz.

2.4 kHz.

4.2 kHz.

15 kHz.