ECE 563 HW6 F13

What local oscillator frequency would we use to tune

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Unformatted text preview: nt positive values of f 0 for which the system output has the form € y ( t ) = cos( 4000π t ) . b) Suppose that in an AM superheterodyne receiver design, we decide to put the IF BPF passband above the AM band – say that we set f IF = 1700 kHz. What local oscillator € frequency would we use to tune in a transmitted signal having a carrier frequency of 1200 kHz? What is the image frequency for that signal? c) Find the power and bandwidth of the AM signal € x ( t ) = 10 1 + 0.8 sin(100π t ) cos 2 × 10 5 π t . ( [ [ ) d) The AM signal x ( t ) = A 1 + a cos(2π t ) cos(20 π t ) is shown on the next page. Find the values of A and a . € € € € € € € € € 6. (This is an old exam problem.) Let x ( t ) and h ( t ) be bandpass signals, both having the same center frequency f 0 . a) Suppose that the Fourier Transform of the complex envelope of x ( t ) is € € € # f & . Find the in- phase and quadrature components of x ( t ) . X ( f...
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