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Unformatted text preview: EE-655 HW Problem 1. Write a Matlab script to simulate the phase lock loop shown below. In this problem the input signal to the pll is a sinewave at frequency f1 for N samples then at f2 for N samples. i Phase Acc um ulator e
exp(j--) ji(n) z -1 i(n) e j(n) (n) KP Loop Filter AT AN Ki *
DDS e j(n)
exp(j--) z (n)
Phase Acc um ulator -1 z -1 (n) DDS Use theta_0=2*pi/100; eta=sqrt(2)/2 for loop filter. Let dphi_i= 0.05 for n=1:100 and 0.1 for n=101:200; Generate figures a. Time series of two phase profiles, phi_1, and phi_2 on same plot; use two colors b. Time series of del_phi and Time series of dphi_o on two subplots c. Time series of real parts of exp(j*2*pi*phi_i) and real parts of exp(j*2*pi*phi_o) 2. Write a Matlab script to simulate the phase lock loop shown below. In this problem the input signal to the pll is a phase rotated and then a phase rotating QPSK modulated time series. Shaping Filte r LUT b its SQRT Nyquist F ilter 1-to-4 Pha se Accumulator Ma tched F ilter SQRT Nyquist Filter 4-to-1 Detec t e j(n) *
Phase Accumulator 1-to-4 e
exp(j--) ji(n) e 4 samp le s/sym AT AN (n) i z -1 i(n) j(n)
Loop Filter (n) z -1 DDS (n) DDS Ki z -1 Use theta_0=2*pi/500; eta=sqrt(2)/2 for loop filter, alpha =0.5, and generate 400 input QPSK symbols. For part A have input spinner be constant phase 2*pi/20. For part B have phase spinner be ramp phase with slope 2*pi*0.0001 per sample. Generate figures a. Eye-diagram and constellation at output of Shaping filter. b. Eye-diagram and constellation at output of channel spinner before loop is engaged. c. Eye-diagram and constellation at output of matched filter before loop is engaged. d. Eye-diagram and constellation at output of matched filter after loop is engaged. e. Phase error, loop filter output, and phase profiles of two accumulators (2-colors) ...
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This note was uploaded on 05/10/2010 for the course ECE 655 taught by Professor F.harris during the Spring '10 term at San Diego State.
- Spring '10