EE 2212

PROBLEM SET 2

S. G. Burns

Due: Wednesday, 1 February 2017

Note 1: Again, a reminder that some of the WEB browsers such as Firefox and shareware versions of Internet Explorer and Chrome and its derivatives may not display or print SYMBOL and ADOBE fonts correctly. There are also some issues with iOS. Also, shareware versions of WORD and WORD without the embedded symbol font may also have issues in this regard. For example, 1 kW should show as k followed by Greek upper case omega. If it displays or prints as 1 kW you have an issue with all Greek symbols! This could lead to errors with units since micro ”μ” will read as “m” and so forth which yields an error of 10⁹!!! Be careful.

Note 2: Unless otherwise stated, assume all operational amplifiers are ideal. Therefore you should use the summing point constraints to significantly minimize algebraic complexity.

1. Figures P12.3, P12.5, P12.6, P12.9, 12.14, and P12.17 (pages 759 and 760) are cascaded operational amplifier circuits. Compute the voltage gain, = v_O/v_I for each circuit. Believe it or not, when you use summing point constraints and the circuit topologies we discussed in class Monday and Wednesday of this week, the voltage gain computation for each circuit can be done in ONE line! Also for added practice, compute the voltage gain in dB for each circuit.

2. Adapted from an old quiz. A 4-Bit DAC circuit is given. Text 1.42 is useful as guidance to work this problem.

Refer to the graphs for V1, V2, V3, and V4.Assume the digital pulse amplitudes are all 1 volt.

(a) Specify a set of self-consistent values for R2, R3, R4, and Rf. Note that R1 = 16 kW.

(b) Sketch and label the DAC output voltage, Vout, on the set of axes provided.

(c) Consider the following design issue. Suppose I wanted to continue this approach to the design of an 8-bit DAC

(Digital-to-Analog Converter). Is this circuit design approach a good idea? Why or why not? To guide you in your

answer, consider the resistor ratios and resistor accuracy required of these ratios for achieving an accurate 8-bit DAC.

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3. Active Analog Filter Topologies

You already know from our class discussions that Circuit 1 is an active analog Low-Pass Filter. For each of the remaining three circuits, state whether the circuit will function as a low-pass or high-pass filter. Each of your answers must be accompanied by a brief explanation and justification incorporating the frequency dependent characteristics of the reactive circuit elements. That is you should look at the asymptotic impedance of the L and C if the input signal the frequency is very low or very high. No equations are required!

3. You decide to have a loud noisy party this weekend with great music instead of studying EE 2212 or at least delay your studying until the next day or whenever you recover. Suppose your 300 watt audio system yields an 80 dB signal as measured by the police in response to a noise ordinance complaint by a neighbor who you should have invited to your party. http://www.industrialnoisecontrol.com/comparative-noise-examples.htm

(a) If the noise ordinance limit is supposed to be 65 dB at the lot line, at what power level should you run your system?

(b) Suppose you suggest to the police , politely of course, so that you can avoid getting a minor for other possible infractions at your party, that the noise measurement be taken further away than the lot line. As an engineering student doing well in EE 2212, how much further away should the noise measurement be taken? You may assume that measured audio power is proportional to 1/r² where r is the distance from your speakers to the point of measurement. Your answer will be a distance ratio.

Many municipalities prohibit sustained noise that exceeds a certain decibel level. The decibel limits are set according to the time of day and the neighborhood zoning. When a neighbor complains, police place decibel level monitoring equipment on an estimated property line and take a reading.

4. Similar to Problem 2 in the design approach. Since I have been taking guitar lessons (I am not very good which means I should practice more). Again use summing amplifier design ideas for guidance to design the electronic preamplifier for an electric guitar.

There are six strings on an electric guitar and their frequency and musical note relationships are shown in the table. Each of the magnetic pickups for the six strings will be modeled as six signal sources v₁(t), v₂(t), v₃(t), v₄(t), v₅(t), and v₆(t).

DESIGN an operational amplifier system (guitar preamp/audio equalizer ) such that the resultant output, which you would listen to as the sum, meets the individual string amplitude specifications given in the last row of the table. .

Again, assume an ideal operational amplifier which allows you to use summing point constraints, however resistor values must be compatible with a mA 741, that is all resistors > 2kW. Your design must include a detailed, well-labeled circuit diagram showing six inputs; one for each string’s magnetic pickup transducer.

String 1 High E	String 2 B	String 3 G	String 4 D	String 5 A	String 6 Low E
v1(t)	v2(t)	v3(t)	v4(t)	v5(t)	v6(t)
f1 >	f2 >	f3 >	f4 >	f5 >	f6
14 dB	20 dB	6 dB	-6 dB	26 dB	30 dB Nice bass boost

5. From an old quiz. For each of the two separate circuits shown below, obtain an expression for the voltage gain defined by . Assume ideal operational amplifiers. Use summing point constraints. Also observe that Circuit 1 is best solved by using a Thevenin equivalent circuit for the input network, node defined by R1, R2, and R3.

These cartoons obtained from a friend raiding a secret stash of cartoons at a well known laboratory instrument company.

UNITS ARE ALWAYS AN ISSUE TO REMIND YOU OF THE BASIC CIRCUIT ELEMENT DEFINITIONS

This may help with your understanding of DACs and ADCs

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BTO SUPPORT YOUR UNDERSTANDING OF dB AN IMPROVED PHYSICS I LAB

And more from my files of good stuff:

And last but not least. General wisdom of the ages because I am not a fan of the

continual pain in the butt requests to update something or other in WINDOWS.