Question

Q2. (a) Determine the Fourier transform of a Hann (sometimes called a raised cosine) window function h(t) of width T, defined + cos 2 0 (b) Sketch the form of a sinusoidal waveform of frequency vo as observed on a spectrum 4] analyser with the Hann window function enabled. Assume voT> 1. Q3. A television receiver uses the superheterodyne detection system to translate signals to an intermediate frequency of 44 MHz. Terrestial digital television broadcasts in the U.K. since 2012 have a carrier frequency in the range 470 to 790 MHz. (a) What range of frequencies for a local oscillator is necessary to be able to receive 4] signals across this band? If there is a strong mobile telephone signal transmitted at a frequency of 817 MHz, what[4] is the frequency of the television broadcast that would be susceptible to interference by this image frequency in superheterodyne detection? (b)

Answer 1

CA 0 ( 2 20 (20 (20