Intermediate frequency filter and amplifiers Broadband radio frequency bandpass filter Detector r(t) m~(t)Local Oscillator)2cos(tfLOπFig. 3-1 Suppose someone has designed a superheterodyne receiver (Fig.3-1) to receive radio stations that use the frequency band [2,1CCff] = [108 MHz, 157 MHz]. This superheterodyne receiver is designed to use low-side injection down conversion (i.e. the local oscillator frequency is less than the carrier frequency it is down converting; CLOff<) to the intermediate frequency IFf. (a)The initial design of the superheterodyne receiver used an intermediate frequency of 12=IFfMHz. Find the image frequency band (i.e. find [fimage1, fimage2], where fimage1is the image frequency for 1Cf= 108 MHz and fimage2
has intentionally blurred sections.
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