An AM radio station operating at 630 kHz is permitted to broadcast audio frequencies up to 6 kHz. The band pass filter in its modulation circuit can retain the frequencies

Options

A. 636 kHz , 624 kHz
B. 12 kHz, 6kHz
C. 1260 kHz, 6kHz
D. 1260 kHz, 630 kHz

Answer

A

Explanation

The band pass filter retains the frequencies `v_(c),v_(c)-v_(m)` and `v_(c) + v_(m)` and rejects the frequencies `v_(m),2V_(m)` and `2v_(c)`
Here `v_(c) = 630 kHz, v_(m) = 6 kHz`
`therefore ` The frequencies retained by the band pass filter are `v_(c) = 630 kHz`
`v_(c) - v_(m) = (630-6) kHz = 624kHz`
`v_(c)+ v_(m) = (630 + 6) kHz = 636 kHz`