EE 541 University of Southern California Viterbi School of Engineering J. Choma. Final Examination Solutions 1 Fall Semester, 2010 UUUniversity of SSSouthern CCCalifornia USC Viterbi School of Engineering Ming Hsieh Department of Electrical Engineering EE 541: Final Examination 14 December 2010 (SOLUTIONS) 11:00 -to- 1:00 Problem #1: Solution — — — — — — — — (25%)The circuit shown in Figure (E1) is a simplified model of a MOSFET technology amplifier that combines shunt peaking via the inductance L1with series peaking through induc-tance L2to achieve a broadbanded network. The two inductances utilized in the circuit are un-coupled. The input signal is the voltage, Vs, while the output response to this signal is voltage Vo. It can be demonstrated that the input/output voltage transfer function, Hn(p), normalized to the voltage gain realized at zero frequency is of the form, 2n221kQpH (p),1pQp+=++where “p”is complex frequency “s”normalized to the uncompensated circuit bandwidth, say Bu. Specifically, Burepresents the radial 3-dBbandwidth that is realized when L1= L2= 0. g VmsL1L2RLCLVoFigure (E1) (a).Determine parameter “k”in terms of the two inductances, L1and L2. The input/output (I/O) transfer function, H(s) = Vo/Vs, is easily confirmed to be ()()()1L1LoLmmL2sLL12LL12L1sLRsL1sCVRH(s)ggR,1V1sR CsLLCRsLsLsC⎡⎤⎛⎞⎡⎤++⎢⎥⎜⎟⎢⎥⎝⎠⎢⎥⎢⎥== −= −⎢⎥⎢⎥++++++⎢⎥⎢⎥⎣⎦⎢⎥⎣⎦(E1-1) where the zero frequency value, say H(0), of the I/O voltage gain is clearly seen to be –(gmRL). Moreover, we note that when L1= L2= 0, the transfer relationship in (E1-1) reduces to 12LL0LLH(0)H(s),1sR C===+(E1-2) which clearly projects an uncompensated 3-dBbandwidth, Bu, (i.e. the bandwidth of the circuit with the inductors replaced by short circuits) of
has intentionally blurred sections.
Sign up to view the full version.