HomeworkAssignment02Solution

Using an excell then further

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Unformatted text preview: | | ⁄ ⁄ ) ⁄ ⁄ . Thus, the CMMR is ( 11 ) 55:041 Electronic Circuits. The University of Iowa. Fall 2011. Question 1 1 With inputs With inputs expressed in dB. (5 points) , and , the output is , a difference amplifier has output . Determine the CMRR, Solution The differential input voltage is ⁄ is With , and the differential-mode gain ⁄ the common-mode voltage gain is The common-mode rejection ratio is | | | Expressed in dB 12 | 55:041 Electronic Circuits. The University of Iowa. Fall 2011. Question 1 2 (J&B 6 th, P11.84) The multimeter in the figures below has a common-mode rejection specification of 80 dB. What possible range of output voltages can the meter indicate? (6 points) Solution The difference voltage is , and the common-mode voltage is ( ⁄ A common-mode rejection specification of 80 dB means that the multimeter will suppress by a 80 dB, which is equivalent to a factor The contribution of the common-mode ⁄ error is thus . However, the sign is unknown. Thus, the multimeter could display anything in the range 13 55:041 Electronic Circuits. The University of Iowa. Fall 2011. Question 1 3 (J&B 6 th, P11.85) We would like to measure the voltage in the circuit below with a voltmeter. What is the value of , and what is the common-mode voltage associated with ? What CMMR is required of the voltmeter if we are to measure to within 0.01%? Express you answer in dB. (8 points) Solution The current through the resistance is therefore 3.75 V. Further, is then ( ⁄( . The voltage across the , and resistor is The common-mode voltage ( The error must be less than or or 3.75 V, which is 0.375 mV. Thus, the multimeter must suppress the 7.5 V common-mode voltage to less than 0.375 mV. In other words, the CMMR must be at least This is equivalent to 86 dB. 14 55:041 Electronic Circuits. The University of Iowa. Fall 2011. Question 1 4 Suppose the amplifier below has a differential-mode gain of 2,500 and a CMMR of 80 dB. What is the output voltage if , and ? What is the error introduced by the finite CMMR, expressed as a % of the differential input voltage? (5 points) Solution The differential-mode gain is 2,500 and the common-mode gain is 80 dB less, which corresponds to a ⁄ ⁄( factor . Thus, the common-mode gain is . The output voltage is ( ( ( The error is 15 ( 55:041 Electronic Circuits. The University of Iowa. Fall 2011. Question 1 5 A current source has an output impedance of . Design a current-to-voltage converter with an output voltage of when the signal current is . (6 points) Solution The following circuit is a current to voltage converter, with output voltage ( 16...
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This note was uploaded on 10/26/2013 for the course ECE 55:041 taught by Professor Kruger during the Fall '11 term at University of Iowa.

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