Q1. Prepare the sketch the Fourier transform of a rectangular pulse of amplitude 10 V and width 0.1 second that is centered on the zero time axis. Show the amplitude at dc and for the first spectral peak. Also show the frequency of the first spectral peak and points of zero amplitude.
Q2. The signal exp(-3t) u(t) is delayed 0.1 seconds and subtracted from itself. Evaluate the Fourier Transform of the output signal? Show a block diagram of the system. What is the Transfer Function of the system, H(f)?
Q3. Determine the autocorrelation function of a rectangular pulse with an amplitude of 5 volts that exists between t = 0 and t = 10 seconds? Show your answer (a graphical solution is OK).
Q4. A signal, x(t) = 2 sin (10π 106 t), is applied to the input of an RC lowpass filter with a cutoff frequency of 1 MHz. Determine the output signal? How many dB is the output signal relative to the input signal?
Q5. Evaluate the instantaneous frequency of a signal v(t) = 5 cos (10πt + cos 5πt) at t = 10 seconds.
Q6. A 100 MHz carrier is frequency modulated by a 1 kHz sinusoidal signal and has a peak frequency deviation of 2 kHz. Draw the spectrum of this signal. Show the frequency and amplitude (relative to the unmodulated carrier level) of at least the first 2 sidebands.
Q7. Sketch the constellation patterns (magnitude and phase) of a BPSK, a QPSK and an 8PSK digitally modulated signal. If all three kinds of signals occupy the same bandwidth, what is the ratio between their relative maximum information transmission rates?
Q8. Show that a Hilbert transform of a Hilbert transform of a signal is the negative of itself.