- Can You Solve This Question 1 (123.39 KiB) Viewed 23 times
Can you solve this question?
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answerhappygod
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Can you solve this question?
Can you solve this question?
Question 2. (25 points) The baseband signal m(t) = ux(t) is amplitude modulated (AM) on a carier wave with frequency f. = 1000 kHz, with x(t) = 2 cos 1500xt+3 cos 4500zt (which has a peak value of 5), and modulation index μ. The amplitude of the unmodulated carrier wave, i.e. when m(t) = 0, is equal to 4 = 200 V. a) Write down the fully worked out mathematical expression that describes the AM modulated bandpass signal and show, based on this expression, that this AM bandpass signal consists of a number of discrete frequency components. Provide the frequencies (in Hz) of these components. b) Calculate the modulation-index u for which the ratio between maximum and minimum amplitude of the transmitted signal is 3. Now the modulation index is set to u = 0.15. c) Calculate the following parameters of the transmitted AM bandpass signal: 1. the average transmitted power Pav (in dBV²), 2. the normalized peak envelop power (PEP) PPEP (in dBV²). d) Draw a detailed graph of the single-sided power spectrum of the transmitted AM signal. Take as horizontal axis the frequency range from 995 - 1005 kHz and clearly indicate the values on the vertical axis in dBV2/Hz or dBV², as required.
Question 2. (25 points) The baseband signal m(t) = ux(t) is amplitude modulated (AM) on a carier wave with frequency f. = 1000 kHz, with x(t) = 2 cos 1500xt+3 cos 4500zt (which has a peak value of 5), and modulation index μ. The amplitude of the unmodulated carrier wave, i.e. when m(t) = 0, is equal to 4 = 200 V. a) Write down the fully worked out mathematical expression that describes the AM modulated bandpass signal and show, based on this expression, that this AM bandpass signal consists of a number of discrete frequency components. Provide the frequencies (in Hz) of these components. b) Calculate the modulation-index u for which the ratio between maximum and minimum amplitude of the transmitted signal is 3. Now the modulation index is set to u = 0.15. c) Calculate the following parameters of the transmitted AM bandpass signal: 1. the average transmitted power Pav (in dBV²), 2. the normalized peak envelop power (PEP) PPEP (in dBV²). d) Draw a detailed graph of the single-sided power spectrum of the transmitted AM signal. Take as horizontal axis the frequency range from 995 - 1005 kHz and clearly indicate the values on the vertical axis in dBV2/Hz or dBV², as required.
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