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MINOR 3 (2012)
(EEL375) EMBEDDED SYSTEMS
Time: 1 Hours 20 minutes Max. Marks:
20------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
NAME: Entry
No.-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
N. B.: Do the calculations on continuation sheet provided. This
is open book/notes examination,but transferof notes to each other
is strictly prohibited. I T INCLUDES BONUS QUESTION AS WELL .
Q1:-A piezo-electric sensor is attached to steam turbine, which
has constant pressure as well as a
cyclic (fluctuating) pressure. The circuit diagram for
processing the output of the pressure sensor
prior to digitization is given in Figure below. The above sensor
which is attached to this circuit has asensitivity of approximately
1 mVper mili-bar and can tolerate up to maximum 30mili-bars.
The
outputs Vband Vfare the constant pressure signal and the
fluctuating signal respectively. (4)
Given: R1= 10 K. Ohm, R3= 50 K. Ohm. R5= 10 K. Ohm, C6= 47
Nano-Faradand noise is 50Hz and higher.
(a) Both the second stage outputs are digitized and to minimized
the cost of manufacture they will both bedigitized by the same
device (A/D converter) which has a 06 Vinput range. Given that the
observedfluctuations are up to 3milli-bars (at the input). What
overallgains should the twobranches (Vband Vf
branches) of the circuit have?
CALCULATION AND ANSWER:
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(b) The first stage should have a gain of 25. What value should
R2be set to?
CALCULATION AND ANSWER:
(c) What is the purpose of C4? What value should it and
R4therefore be set to given the decisions made so
far?
CALCULATION AND ANSWER:
(d) The second stage for Vfis configured as a passband with an
upper cut off of X Hz. What purpose doesthe capacitor C5serve? What
value should R6be set to (If C5= 100micro farad)? Give 2
ndstage gain for
branch Vf. What is lower and upper cut off frequencies of this
branch?
CALCULATION AND ANSWER:
Q2:- In an intensive care unit (BP) blood pressure (Diastolic,
in mm Hg) and (T) body temperature
(In degrees Fahrenheit) are monitored continuously to control
the (F) flow rate (In liters per hour) of
medicines mixed in saline.
Triangular membership for each fuzzy set is assumed for
composition:
BPLOW (60, 80, 100)
BPMEDIUM (80, 100, 120)
BPHIGH (100, 120, 140)
[Hint:BPHIGHimplies that for crisp value of BP the grade of
membership is 0 at 100 and 140
whereas it is 1 at 120 and the shape is triangular.]
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For temperature:
TLOW (95, 97, 99)
TMEDIUM (97, 99, 101)
THIGH (99, 101, 103)For flow rate:
FLOW (0.9, 1.1, 1.3)
FMEDIUM (1.1, 1.3, 1.5)
FHIGH (1.3, 1.5, 1.7)
If the two fuzzy rules are as:
(a) If ( BP is BPLOW ) OR ( T is TMEDUM ) then (F is FLOW)
(b) If ( BP is BPMEDIUM ) OR ( T is TMEDIUM ) then (F is
FMEDIUM)
(c) If ( BP is BPMEDIUM) AND ( T is THIGH) then (F is FHIGH)
If the temperature is 99.50F and BP = 85 mm Hg, Find the
approximate crisp value of F
using any two methods. Discuss the results and selection of
method. (3)
CALCULATION AND ANSWER:
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Q3:- Using operational amplifiers and AD590 design a Celsius cum
Fahrenheit thermometer
having two outputs OP1and OP2with the given guidelines.
(4)(1)
To convert from Celsius to Fahrenheit: multiply by 1.8and add
32.
F = 1.8 C + 32 AND K = C + 273.
(2) AD590gives a change of one micro ampere per degree
Kelvin.
(3) Resistances available in laboratory are all standard values
between 10 K. Ohm and 1 M.Ohm.
(4) The circuit should give 2.12volts for boiling water
temperature at OP1and 1.00 volt at
OP2. At freezing temperature (water) it should be respectively
0.32 volts and 0.00 voltsat OP1and OP2.
(5) Mention gain of each stage and highlight add/subtract
voltages as well.
(6) Draw the circuit neatly below. Use 1 K. Ohmresistor in
series with AD590 to get
voltage.
Answer:
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Q4: - Consider the fuzzy cruise control problem in a car where
the car speed is to be kept at a
desired value. The inputs are Speed and Accel (short for
acceleration or rate of speed change), and
the output (control action) is amount of Fuel. Assume that
higher fuel increases the car speed. The
shape of membership functions for Speed, Acceleration and Fuel
are the same as given below, butthey have different values of a, b,
c, d, e. The fuzzy sets are LO (low), MD (medium) and HI
(high).
For Speed, (a, b, c, d, e) = (15, 30, 45, 60, 75), for Accel,
(a, b, c, d, e) = (-4, -2, 0, 2, 4), and forFuel, (a, b, c, d, e) =
(10, 20, 30, 40, 50). (5)
Suppose we have the following 4 rules:
1. If Speed is LO and Accel is MD then Fuel is HI
2. If Seed is LO and Accel is HI then Fuel is MD
3. If Speed is MD and Accel is MD then Fuel is MD
4. If Speed is MD and Accel is HI then Fuel is LO
(a): Write a reasonable rule for the case where Speed is HI and
Accel is LO.
(b): Write a reasonable rule for the case where Speed is HI and
Accel is MD.
(c): Suppose the rule base consists of six rules (4 given plus
the two you wrote for (a) and (b)above). Suppose also that the
current speed is 30, and the current acceleration is 3.
(C1) What rule is (are) fired, and what is the truth value(s) of
the antecedents of the fired rule(s)?(C2) Very carefully and neatly
draw the total aggregate plot for the fuel, clearly show all
the
important membership values on the plot. Do notperform the
defuzzification.
Answer:-
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Q5:-For the circuit given in figure (3) below answer the
questions. (4)
Here 3M3implies 3.3M. Ohm and similarly others.
(a) - What is the D.C. gain of the input stages (excluding the
rightmost op-amp stage)?
Answer:
(b) - If C1= 2 microfarad what is the lower cutoff frequency of
this circuit?
Answer:
(c) - If C2= 0.0047 microfarad what is the upper cutoff
frequency of this circuit?
Answer:
(d) - What is the overall gain of the circuit at the midband
frequency?
Answer:
