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Unformatted text preview: Page 1 Score = EEL 4744C Dr. Gugel Print Your Last Name _____________________________________________________ Spring Semester 2010 Final Quiz Print Your First Name ____________________________________________________ Open book/open notes, 90 minute examination. Calculators are permitted. No laptops or cell phones. iPADs allowed. Page 1 17 points _________________ Page 2 17 points _________________ Pages 3 & 4 16 points _________________ TOTAL 50 points _________________ A/D & D/A Conversion You are given a microphone that has a maximum output span of 100mV . It is attached to a pre-amplifier that has split supply rails of +/- 9V (using standard 9V batteries) and a gain of 50 . Assuming that a 14 unsigned A/D will be used to digitize the signal coming from the pre-amplifier answer the following questions. 1. Assuming that the A/D converter is also powered from the two 9V batteries, what should the reference voltages be set to on the A/D converter assuming that the device is DC coupled? i.e. There is no large capacitor blocking DC between the pre-amplifier output and A/D converter? Assume we desire maximum accuracy when digitizing the analog signal. (2 pt.) 2. If the A/D voltage references have been set to +/- 6V (to have 3V headroom with respect to the power supply rails), what is the resolution and accuracy of the A/D system? (4 pt.) 3. If the A/D references have been set to +/- 6V, what digital value is expected (in decimal) for a +2.57V analog input? (3 pts.) 4. If the A/D references have been observed to have +/-5mV of noise on them, what is the dynamic range of the A/D and what is the new expected digital output range for a +2.57V analog input? (4 pts.) 5. If the A/D references are again +/- 6V and the span of the input analog signal on the A/D converter has been observed to be +/- 7V, how will the frequency content of the input signal be altered by the clipping? Be very specific in your answer for maximum points. Also, if there is no low pass filter on the input to the A/D how can this cause additional problems? (4 pt.) ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Page 2 Score = 6. You are given a Signed 14 bit D/A with a reference span set to 3.3V , what is the expected output for 0x3EEE ? (3 pts.) 7. Using the above D/A converter, what four values (samples) should be sent to the D/A to create a triangle wave that...
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- Spring '09