electricalstudent Latest Questions
Problem #I Linear Amplifiers (40 pts) (SHOW ALL WORK) In the Problem, all resistor values are in ohms, voltages are volts and currents are amps. Amp “A” is voltage-to-current, Amps “B” and “C” are current-to-voltage. Use /1 = 0.01(V1), v2 = 100(/2) and V3 = 50(/3). Use Vin shown in the table. Find all the values listed in the table. Hint: Observe that R3, R4 and R5 are m parallel.
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)
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)
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)
Asked: October 6, 2022In: electrical machines