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# La regola di S. Benedetto - Monachesimo - Appunti - Storia del diritto medievale e moderno , Appunti di Giurisprudenza. Pontificia Università degli Studi San Tommaso d'Aquino

## Giurisprudenza

Descrizione: Approfondimanto monachesimo per storia del diritto medievale e moderno

Name (Last, First) UNIVERSITY OF CALIFORNIA College of Engineering Electrical Engineering and Computer Sciences Department EECS 145M: Microcomputer Interfacing Laboratory Spring Midterm #2 Monday, April 21, 1997 • • • Closed book- calculators OK Many equations are listed at the back of the exam You must show your work to get full credit PROBLEM 1 (50 points) Design a computer controlled system for the automatic testing of 12-bit A/D converters. You are provided with the following: • A microcomputer equipped with a 16-bit parallel input port, and a 16-bit parallel output port. • A 16-bit D/A converter with ±1 LSB absolute accuracy. You may assume the following: • The 16-bit parallel output port is in “transparent” mode. A 16-bit word A written to the output port using the command outport(1, A ) immediately appears on the output lines. • The 16-bit parallel input port requires a low-to-high edge on a “strobe” input line for external data to be latched onto the 16 bit registers. The program can read these registers using the command B = inport(1). • The parallel input port has an “input data available” line that can be asserted high or low by an external device and read by the program using the command C = inport(2). • The parallel input port has an external “ready for input data” line that can be set high using the program command outport(2,1), and set low using outport(2,0). • The A/D converter requires a “start conversion” low-to-high signal and after conversion provides a “data ready” low-to-high signal that goes low when “start conversion” goes low. • The A/D reference voltages are Vref– = 0.0000 V and Vref+ = 4.095 V • The D/A reference voltages are Vref– = 0.0000 V and Vref+ = 4.096 V EECS145M 1997 Midterm #2 Page 1 Derenzo Name (Last, First) 1 a. [25 points] Draw a block diagram of the major components, including the A/D circuit being tested. Show and label all essential components, data lines, and

control lines. 1b. [10 points] How would you measure the maximum absolute accuracy error of the A/D? (Explain the procedure in steps or with a flow diagram.) EECS145M 1997 Midterm #2 Page 2 Derenzo Name (Last, First) 1 c . [5 points] How would you measure the maximum linearity error? 1d. [5 points] How would you measure the maximum differential linearity error? 1 e . [5 points] With what accuracy could this system measure the quantities in parts b . , c . , and d. in units of 1 LSB of the A/D? PROBLEM 2 (50 points) Design a microcomputer-based system for using the FFT to analyze the harmonic content of musical instruments. The design requirements are: • The instruments have a fundamental frequency (first harmonic) ranging from 50 Hz to 2 kHz. • The system must sample the waveform with an amplitude accuracy of ±1% over all frequencies of interest. • The system must compute harmonic magnitudes from the 1st to the 15th harmonic with an accuracy that is 0.2% of the largest harmonic. (You may assume that at and above the 15th harmonic, the magnitudes decrease with increasing frequency.) • Neighboring Fourier coefficients correspond to frequencies differing by 0.5 Hz. EECS145M 1997 Midterm #2 Page 3 Derenzo Name (Last, First) 2 a. [10 points] How does your design avoid aliasing? Give details. 2b. [10 points] What is the minimum sampling frequency required? 2 c . [5 points] What is the minimum time needed to take all the required samples? 2d. [5 points] What is the minimum number of samples required? EECS145M 1997 Midterm #2 Page 4 Derenzo Name (Last, First) 2 e . [5 points] Would a Hanning window be useful in your design? Explain your reasoning. 2 f . [5 points] To what frequency does the first FFT coefficient H1correspond? 2 g . (10 points] For a musical instrument with a first harmonic frequency of 500 Hz, which FFT magnitudes would you expect to be non zero? Equations, some of which you might find useful: G(a ) =  1  a −µ 

2   exp  −   2 σ   2 πσ2 1 1 µ ≈ a = m ∑ ai i =1 m  1

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