EE 391 (All Sections) Midterm Examination Tuesday, November 2,2004 7:00 PM Time Allowed: 2 Hours Materials allowed: Laboratory Notebooks, Calculators Instructions: Answer all questions in the space provided (use page backs for rough work if necessary) State your assumptions; show all relevant work. Box, circle or otherwise highlight your answers where appropriate. For multiple choice, circle the correct answer. Put your name and student number on each page; (we may separate them for marking purposes) Refer to the last page for relevant product data when required Weighting for each question is indicated in the left margin (Total marks: 120) Name: ~ Y J !,AJ&s~ Student Number: 4610( 6 (Marker 's use only.) Fourier I20 2ndOrd I20 S. L. 120 BJT I1 5 Op A 120 FET I1 5 Total 14-40
Answer all questions in the space provided (use page backs for rough work if
necessary)
State your assumptions; show all relevant work. Box, circle or otherwise highlight
your answers where appropriate. For multiple choice, circle the correct answer.
Put your name and student number on each page; (we may separate them
for marking purposes)
Refer to the last page for relevant product data when required
Weighting for each question is indicated in the left margin (Total marks: 120)
Name: ~ Y J !,AJ&s~
Student Number: 4610( 6
(Marker 's use only.)
Fourier
I20
2ndOrd
I20
S. L.
120
BJT
I1 5
Op A
120
FET
I1 5
Total
14-40
EE 391 Midterm Examination Nov. 2,2004
Timing in Sequential Logic
Ql.1) Analyze the following circuit made from two 7400 TTL logic chips (Note: some potentially useful information in the Appendices).
average propagation delay, tp, for the NAND gates used
d Sketch the approximate waveform at the output on the 'scope screen at right. Be sure to label the axes and their scales. Show any supporting calculations you may need to make.
' rhi3 2
in this
+iFr)
circuit?
0d) Desim a simole astable oscilla~ w tor using a single 4069 CMOS Hex-inverter chip so that it ' could be use2 as a clock source for a counter circuit. Show the necessary wiring connections
on the drawing below. Design for a $lock frequency of 5MHz (Assuming "typical" ,
operation). - 2 -- @J,~s ; as- B
A , % ~ ~ V\I~WJ-LJ Me 614 6 &e4'cf-*&fl8
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I
Name: kyl LMS Student #I " I i i n / b Page 2 of 16
EE 391 Midterm Examination Nov. 2,2004
Consider the basic inverter circuit shown below driven by a 10kHz TTL square wave from the signal generator.
+ 5 v + 1 o v
$330 1 3 3 0 Output Wavefom -
w v (to 'scope Ch 2) Signal 7400 4 2N4124
Generator - -
The oscilloscope trace of the input and output f' aveforms are shown at right. Determine the values of the following parameters if shown, and label them on the 'scope figure.
151 i) ~ P H L ~ ~ S - S ~ O C C , ~ ii) ~ P L H 6" iii) ~ T H L -YS- iv) ~ T L H f i & 9 n 5 Y J
Input Wavefom (to 'scope Ch 1)
41.4) A piece of electronic Laboratory equipment is labeled "74C7". Describe briefly, but specifically, where this piece of equipment should be stored.
121 You, S ~ O ~ U A g,,r+zn Awn pc7T k~7Lt ~ ~ I J s yo cc h >+5p~odd 9kw be PIQ& h $b %If 3
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i?. ri7 ~~~k 7& Y b m +ei)syo~c ~ 0 ) 1 ~ r t > n k
; k 5 h o d d qB4
Name: kulejJtgj student # / 101 6 Page 3 of 16
EE 391 Midterm Examination Nov. 2,2004
BJT Amplifiers 8 Q2.1) 24' Determine whether the following circuit is biased properly for use as an amplifier. State
any assumptions that you make. [41 k 4 - 0 0 ~ e s ~ 3
1 o v &=5wrr .z&
I e o u t
pi55 -a'& ) h p ~ t h u d k 3 e o c ~ - e s R c Q L l r d ~ E %n* O w is - - ' v e ~ ^ , c?
+I-& &-5.~h~iu:ii L Lla~&yhpriy, CXJ IdJ;s the transistor operat~ng in: [ cutoff, active region saturation ? (circle one)
Q ) What is the general expression for the output resistance of the following circuit? f
Name: kv 1~ P Q A ~ student # 9 6 /0/ 6 Page 4 of 16
EE 391 Midterm Examination Nov. 2,2004
. 42.3) The following circuit was designed for use in the EE 391 BJT laboratory. The nominal operating characteristics of the circuit were B 150, Av = -25, ZoUT = 1 OkR, VCE = 4V, and f = 5kHz. The values shown are approximate.
A 4uF capacitor was then placed across the RE= 358R resistor. What changes, if any, must be made to the circuit in order to measure the voltage gain, Av , of the circuit at f = 5kHz? ,
Name: h/& ~ G G Student # q ~ I O / 6 Page 5 of 16
Midterm Examination Nov. 2,2004
Second Order Svstems
I(S) Ql.l)/r(;or the circuit shown in the figure, derive the transfer function H(g=- E(S)
(Assume: Internal resistance of the source is Rs and that of the inductor is RL)
d w r i t e the Characteristic equation for the circuit in terms of R, L and C (where R is the total / ' resistance of the s y s t e m 4 . .
Derive the equations for: i) Undamped natural frequency ii) Damping factor and iii) Damped natural frequency
Name: kre I b% Page 6 of 16
EE 391 Midterm Examination Nov. 2,2004
43 .2 ) The following diagram shows a frequency response curve for a second order system.
a)Hetermine the followings from the diagram: ower and upper cut-off angular frequencies (a, & a2)
of the system in Hz
/ (i) 8- Frequency, Hz
Bw; 1 % 0 - 6 a
j$ If the circuit has a capacitance of 100pF, what are the values of the other passive elements?
l31 k5q& f J-~$LL~I? d w n f d 4 6 h i S
at should the response look like if the resistance of the system is lowered? [Draw it on the same diagram]
l11
10-1 10' 1 o5 v
Frequency, Hz
Name: IS-VILWS Student # Q h i o l b Page 7of16
EE 391 Midterm Examination Nov. 2,2004
the followings from the given diagram: ercentage overshoot
$ Damping factor
[Oscilloscope setting for this diagram is Horizontal setting : 0.1 msldiv Vertical setting : 1 Vldiv]
)What should the value of the resistance be if the values of capacitance and inductance of the !/ system are 100nF and 100mH respectively?
J
R 3
Name: [/I eW8 Student # 4hor 6 Page 8 of 16
Midterm Examination
Fourier Analvsis
FREQUENCY
7 I INTENSITY
0 SWEEP
I I
RESOLUTION BANDWIDTH FREQ SPAWDIV DISPUY smmffi
69 @ Y I I I I U VEWER
INPUT SENSITIVITY INPUT DISPLAY POWER AMPLITUDE MODE AMPLITUDE REF LEVEL
Consider the input waveform and circuit shown above (the input waveform is connected to the Spectrum analyzer which is set as shown):
.
; .
+----
0
at is the value of Vp? 141 5 p ~ + ~ WOJY w r w p dt- 9 h c ~ k & q r/J*
h p so hp ;B & 10 SO ? d B
What is the periodic time 121 \ 1 - -
J
-v, cso
VP a a
Name: kyL V ~ S
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Student # 4110! 6 Page 9 of 16
- - - - -+ ei . t CI 11 0.01 ILF
m Sec. imw a
the transfer function
Midterm Examination
E,(s)/Ei(s) for the circuit shown above. _L
Nov. 2,2004
of the output waveform in
161
I
Name: kl/\ L NVS Student # %(@I 6 Page 10 of 16
EE 391 Midterm Examination Nov. 2,2004
Operational Amplifiers n
Q5.1) Refer to the oscilloscope trace shown above. Channel 1 is the input waveform; Channel 2 is the output. / /
qarOgH d FO - - 2a.a~H3 at is the frequency of the signals?
I [ll
/
of the system in db,? -!S,q dbV [31
3 / w-
613 b X / O -3) ul-po~r - - )+ - 141,~~1'6
/ Ga;.n dB-
/) What is the phase shift (in degrees) of the Channel 2 signal with respect to the Channel 1 signal?
[31
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1 / J$,%% ,3SJI ~ Y C ~ L 3aao Assume you are designing an op-amp circuit that requires a sinusoidal output signal of 20Vp.p at a maximum frequency of 300kHz. What is the minimum slew rate specification for the op amp? (Note: there may be some useful information in the Appendix.)
op amp shown in the figure has a Unity Gain bandwidth of 3MHz and a negligible offset voltage. If an output of +0.63V is observed, what is the magnitude and direction of the input bias current?
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d
5
Name: kyle Student # 4 b / 6 / [ Page II of 16
EE 391 Midterm Examination Nov. 2,2004
FET Am~lifiers r \ Q6.1) The following circuit was used in your FET lab. The nominal operating characteristics of the
circuit were grn =; 0.2S, I, = 50rnA, and Rin > 1 Ok. The values shown are appropriate.
6 . 8 ~ I +------ eout
is the unloaded gain of the circuit from gate to dr 121
/ 12B - Av: ---- -81 - - - -4/$S 4a vRs - h @ b t 14
1.5kHz input voltage source is adjusted to give 1V p-p at eout. The following circuit was then connected to eout. What is the p-p voltage across RL?
151
Name: kvl , . e Y ~3 Student # 76 (01 Page 12 of 16
EE 391 Midterm Examination Nov. 2,2004
P The 1.5kHz input voltage source was replaced by a properly calibrated and buffered pectrum analyzer (as done in the EE 391 laboratory) in order to measure the frequency
response from 1 OHz - 1 OlcHz (the CL-RL load on eout is still connected). Is the value of the input capacitor appropriate for this measurement? DO NOT CALCULATE THE VALUE. CONSULT YOUR EE 391 LABORATORY LOG BOOK FOR THE CORRECT VALUE. Circle one answer below and supply the correct value.
PI
Yes No (too small) No (too big)
Assuming a correct value of C1 is used and with reference to spectrum analyzer front panel below, what are the settings for the following controls if the frequency response from 10Hz - / 10kHz is to be measured and the screen display is to be appropriate.
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