Question

Engineering question. Please provide your work. Please explain how you got each number in your work. Please do not copy your work and answers from other people's links.

4. Superheterodyne receiver For ALL cases given here, the receiver's local oscillator (LO) frequency is GREATER THAN the incoming radio frequency (RF) Image Frequency Incoming RF Receiver's LO Frequency Intermediate Frequency (IF) 455 kHz 455 kHz 10.7 MHz 10.7 MHz 630 kHz 920 kHz 92.3 MHz 101.5 MHz (a) Does any image frequency fall within the (US) AM broadcast band of 530 - 1710 kHz? If so, identify. (b) Does any image frequency fall within the (US) FM broadcast band of 88.1 -107.9 MHz? If so, identify

Answer 1

We will use following formulaes to fill the table

We will use following formulas to fill the table F_LO = IF + Fs here FLO: Local oscillator frequency IF: Intermediate frequency Fs: RF Signal frequency And F_si = F_s + 2IF where Fsi = Image frequency a). Yes, 1540kHz image frequency lies in US AM broadcast band. b).Yes, 112.5MHZ image frequency lies in US FM band.

here FLO: Local oscillator frequency

IF: Intermediate frequency

Fs: RF Signal frequency

And

wher Fsi= Image frequency

Incoming RF: Fs	Reciever LO: FLO We will use following formulas to fill the table F_LO = IF + Fs here FLO: Local oscillator frequency IF: Intermediate frequency Fs: RF Signal frequency And F_si = F_s + 2IF where Fsi = Image frequency a). Yes, 1540kHz image frequency lies in US AM broadcast band. b).Yes, 112.5MHZ image frequency lies in US FM band.	Intermediate Frequency: IF	Image Frequency
630kHz	1085kHz	455kHz	1540kHz
920kHz	1375kHz	455kHz	1830kHz
92.3MHz	102.4MHz	10.1MHz	112.5MHz
101.5MHz	111.6	10.1MHz	121.7MHz

a). Yes, 1540kHz image frequency lies in US AM broadcast band.

b).Yes, 112.5MHZ image frequency lies in US FM band.

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