Tài liệu tham khảo toán học bằng tiếng anh Problems_ Chapter 1, dành cho các bạn sinh viên đại học. | Problems – Chapter 1 Determine the energy spectral density of a square pulse x(t) = rect(t/T). Calculate the normalized energy Ex in the pulse. Find the average normalized power in the waveform x(t) = 10cos10t + 20cos20t. Determine which, if any, of the following functions have the properties of autocorrelation functions. Why? Determine which, if any, of the following functions have the properties of power spectral density functions. Why? The Fourier transform of a signal x(t) is defined by X(f) = sinc f. Find the autocorrelation functions of signal x(t). Given the PSD: . Find the value of signal bandwidth using the following bandwidth definitions: (a) Half-power bandwidth (b) Null-to-null bandwidth (c) 99% of power bandwidth (d) Bandwidth beyond which the attenuation is 35dB (e) Absolute bandwidth. The two-sided PSD S(f) = 10-6f 2, of a waveform x(t) is shown in Figure 1. (a) Find the normalized average power in x(t) over the frequency band from 0 to 10 kHz (b) Find the normalized average power contained in the frequency band from 5 to 6 kHz Questions – Chapter 1 Describe the differences between analog and digital signals Identify three reasons why digital communication systems are better than analog communications systems
