analog and digital communication systems Archives - electricalstudent

Sign Up

Sign In

Forgot Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

Username* Please type your username.

E-Mail* Please type your E-Mail.

Question Title*

Please choose an appropriate title for the question so it can be answered easily.

Category* Please choose the appropriate section so the question can be searched easily.

Tags Please choose suitable Keywords Ex: question, poll.

Details*

Type the description thoroughly and in details.

Ask Anonymously

Captcha* Captcha Click on image to update the captcha.

Please briefly explain why you feel this question should be reported.

Please briefly explain why you feel this answer should be reported.

Please briefly explain why you feel this user should be reported.

Search

Ask A Question

Category: analog and digital communication systems

analog and digital communication systems question and answers solved

Anonymous

Asked: October 7, 2022In: analog and digital communication systems

3. This problem is on the quantization and encoding. Answer to the following: Assume round-off rule for uniform quantization. We have 10 samples from the analog signal and their quantization error qε are found to be distributed as, qε =[0.33, 0.36, -0.38, 0.22, -0.4, 0.07, 0.4, -0.18, -0.25, 0.38] (a) Decide the suitable value of quantization step size ∆. Give reasoning for your answer (3) (b) We assume that qε are uniformly distributed with its probability density function f ∆ (∆) =1 /∆ for the interval [-∆/2, +∆/2]. Calculate the quantization noise power Pqε for the value of ∆ you found in part (a). (3) (c) Per the quantization noise power you calculated in part (b), calculate the signal power S [Watt] if output Signal to Q-zation noise power ratio SNRo = 30 dB. (3) (d) If we encode the quantizer output with binary code with length ‘n’(integer), decide the minimum code length ‘n’ based on the condition given in part (c) (1)

Anonymous

Asked: October 7, 2022In: analog and digital communication systems

2. This problem is about the system response, spectral density and average signal power. Assume you have input signal x(t) to the system h(t), whose magnitude/phase response plots are shown below. From system we expect output signal y(t). (a) Calculate the power spectral density (PSD) of the input x(t), Sx(f), where x(t)= 1 Cos 12πt + 2Cos 26πt (2) (b) Assume input to system h(t) is also x(t)= 1 Cos 12πt + 2Cos 26πt. Write out the Output signal y(t) in the most compact form and calculate the maximum value of its autocorrelation function Ryy(0) (if needed, assume 1ohm load). (5) (c) Do we have power gain or loss ? Specify the amount by calculate the average Power Ratio, Pout/Pin in dB (assume 1 ohm load for input and output) when input x(t) is processed by system h(t) to yield y(t)). (3)

Anonymous

Asked: October 7, 2022In: analog and digital communication systems

1. The time domain signal x(t) = 2 Cos 2π 20 t + 2 Cos 2π 40 t is subject to ideal sampling. (a) Sketch the magnitude spectrum X(f) (show magnitude and frequencies) (1) (b) Identify the minimum sampling frequency fsmin (in Hz) (2) (c) By using fsmin of part (b), Sketch the Sampled spectrum Xs(f) up to the center frequenc of ±1 fsmin (4) (Do show precise magnitudes and all frequencies up to around ±1 fsmin ) (d) In case when you use sampling frequency of 90 Hz, decide the width of the guard band in [Hz], if you have. (3)

Anonymous

Asked: October 6, 2022In: analog and digital communication systems

3. This problem is on the AM-DSB modulation using single tone message m(t) using carrier c(t), where, m(t) = 2Cos(20πt) and C(t)= 10Cos(100πt). The Modulated Signal is generally written as S(t)=Ac[1+kam(t)] Cos2πfct. Hence Ac =10, and fc=50Hz from C(t) given above. (a) For Ka =0.1, decide the value of modulation index. (2) (b) Decide the maximum value of Ka to avoid envelope distortion. (2) (c) In case of (a), decide the maximum and minimum absolute values of the envelope of the signal S(t). (2)

Anonymous

Asked: October 6, 2022In: analog and digital communication systems

2. (a) For the time domain signal x(t)= 4Cos(2π200)t +8 Sin2 (2π200)t, Find All Complex (Exponential) Fourier Series Coefficients Cn . (5) (b) For the given signal x(t) in Part (a), Find X(f), then Sketch its Magnitude Spectrum in frequency domain.[Sketch both positive and negative frequencies too] (3)

Anonymous

Asked: October 6, 2022In: analog and digital communication systems

1. Find the most compact form of Fourier Transform X(f) of the time-domain signals x(t) below (both part (a) and (b)) using Fourier Integral. [Should show the result by the calculation of Integral !]

hwmadeeasy

Asked: September 30, 2022In: analog and digital communication systems

The op amps are ident and operating in the linear region.

Anonymous

Asked: September 21, 2022In: analog and digital communication systems

Problem 8 Consider a superheterodyne receiver for standard AM radio. a. Sketch a block diagram of the superheterodyne receiver showing the major blocks. b. If you wish to receive a radio station at 1600 ��, what local oscillator frequency is needed? (Let �� = 455 ��) c. What is the “image station” we need to watch out for using this local oscillator frequency? d. Sketch example spectra to illustrate how the local oscillator effectively shifts a transmitted signal spectrum centered at 1600 �� to on that is centered at 455 ��.

Anonymous

Asked: September 21, 2022In: analog and digital communication systems

Problem 7 Consider a single sideband amplitude modulation suppressed carrier (SSB-SC). Let the message spectrum be that shown in Problem 6 and let a. Sketch a block diagram of the SSB-SC transmitter system showing a mixer, filter, and antenna. Label the signals at the different stages of your transmitter. b. Sketch the frequency response �(�) of the minimum bandwidth filter needed by your transmitter to generate proper SSB-SC. Note you may use an upper side band or lower sideband filter (your choice). c. Sketch the spectrum of the signal at the antenna of your system. Label the spectrum in a manner consistent with your notation in a.

Anonymous

Asked: September 21, 2022In: analog and digital communication systems

Problem 6 Consider a carrier, , that is periodic with period 0 = 100 and Fourier series coefficients of

1 2 … 53