The following non-coherent demodulator is used to demodulate an AM signal given by XAM(t) = [A+m(t)]...
When the message signal m (t) =cos (2π fmt) and the carrier signal is c(t)=cos (2π fct) , fm<< fc, The modulated DSB-SC signal SDSB-SC=m(t)cos(2πfct) is generated, and only the upper sideband To generate and transmit the SSB signal. As shown in the figure below, the receiver is a local oscillator cosine signal to the received signal and passes it through a low-pass filter. Answer the following questions. (a) Draw the waveform of DSB-SC modulated signal SDSB-SC(t) (b)Find the result...
1. DSC-SC Modulation. Consider a message signal m(t) = 3 sinc(10t) this is applied to a product modulator with a carrier wave c(t) = 2 cos(100nt). (a) (5 points) Find and plot the Fourier transform S(f) of the DSB-SC modulated signal s(t). (b) (5 points) What is the bandwidth of s(t)? (c) (5 points) The signal s(t) is next applied to filter h(t), the output of the filter is named y(t). Now assume that I $2/300, If|< 30, H(f) =...
Q1. A single-tone FM signal which can be expressed as, s(t) = 4, cos[2oft+ß sin(21f „t)] is applied to a square-law device with output voltage v2 related to input voltage vi by vz(t)= av (t) where a is a constant. a. Determine analytic expression of the output signal. b. Explain how such a device can be used to obtain an FM signal with a greater frequency deviation (Af) than that available at the input. Q2. The spectrum of a message...
1. Given the following AM rectifier detector circuit and its input and output signals: a t m()] cos RIr) LA + m(o) ? m(1) Low-pass A + m()) cos m(t) a. [40 points] Find Va(t), the modulated input signal into the low-pass filter. b. [10 points] Show that (1/T)m(t) is the signal across the output resistor R.
PROBLEM 12 The message signal m(t) is a rectangular pulse of unit amplitude and duration T (centered about the origin). The radio-frequency (RF) pulse defined by s(t) = {4_cos(wt), -āsts 1 0. Otherwise a) Drive a formula for the spectrum of s(t) and v(t) assuming that WT. >> 211 b) Sketch the magnitude spectrum of s(t) for w.T. = 20 The below figure describing the modulation and the demodulation of the m(t) signal. VO mo Product modulator Product modulator Low-pass...
The input r(t) to a DSBSC receiver is a DSB signal s(t) = A m(t)cos (21fet) corrupted by additive white Gaussian noise with two-sided power spectral density N,/2, where No = 10-12 W/Hz, m(t) is a message signal bandlimited to 10 kHz. Average power of m(t) is Pm = 4 W and Ac = 2 mV. The block diagram of the receiver is shown below. Note that the receiver has filters which have slightly larger bandwidths than a typical DSB...
2. Consider the signal f(t) = 20 cos(5t) + cos(9t) sin(5t) - 7 (a) What is the highest angular frequency present in this signal? What is the highest numerical frequency present in this signal? (b) What is the Nyquist frequency? rate for this signal? Did you use the angular or the numerical (c) If you sample this signal with sampling period T, which values of T may you choose to be in accordance with the Nyquist rate? Choose and fix...
The message signal m (t) = Am cos (2nf, t) is used to generate the VSB signal ( 1-α)AμΑ, aAm A cos [2T(fe+fm)t]+ 2 cos [2T(f-m)t], where 0<a< 1. s(t) 2 Find the expression of s(t), where s(t) is the baseband representation of s(t) The message signal m (t) = Am cos (2nf, t) is used to generate the VSB signal ( 1-α)AμΑ, aAm A cos [2T(fe+fm)t]+ 2 cos [2T(f-m)t], where 0
1. The system shown is used for scrambling audio signals. The output signal, y(t) is the scrambled version of the input m(t). Find the spectrum of the scrambled signal y(t): Y(f) Mf) m(t) vt) Low-pass filter 0-15 kHz - (Scrambled output) - 15 kHz | 15 kHz f kHz 2 cos 30,000 t
#2 The following figure shows the block diagram of an AM modulator. mx m()+c) Nonlinear ) y(0) s(0) filter device c)A, cos(2r 1,0) The nonlinear device has an input-output characteristic of the form y() a x(0)+b ) where a and b are constants. Assume that the message signal is m()-A, cos(2, and (a) Determine the signal y). (b) Determine the AM signal s). (c) What kind of the filter is required in the above figure? (d) What is the amplitude...