Department of Electrical & Computer Engineering
ECED - 3203 Assignment 1
Measurement Systems
Due date and time: May 13, 2010, 12:00 noon
in the E&CE Department Oﬃce
1. There are many types of measurement. An understanding of these is useful in the design of measurement
and instrumentation systems. For the following four measurement tasks, identify the type of measurement
required and explain why. The measurement tasks are as follows:
(a) A system to ﬁnd the median potato in a truckload of potatoes.
(b) A system to determine the variation in potato sizes as a percentage of the mean potato size.
(c) A system to determine what percentage of the potatoes are between 100 grams and 150 grams.
(d) A system to inspect potatoes to determine their type.
2. This question will take a little thought. There are many aspects to a measurement task. There are
considerations with respect to:
•
the functional requirements of the measurement, i.e., is a passive quantity being measured such as
an impedance or is it an active one such as a current (I would rather think of this as an aspect of
the source characteristics);
•
the signal characteristics, i.e., periodic signals, transient signals, stochastic signals, continuous sig-
nals, discrete signals, and combinations of these;
•
the spatial organization of the measurements, i.e., how many sensors, where they are situated in the
“space” to be measured, etc. Clearly there is a diﬀerence between measuring temperature, pressure
and acceleration at one point and measuring temperature at 25 points in a furnace 100 metres long;
•
the degree of autonomy provided by the measurement system, i.e., does it require continual human
intervention, or is there a supervisory control system “orchestrating” a large number of measure-
ments?
Now we get to the question. Think of a measurement system of your experience and explain it in terms
of the four categories above. Example measurement systems can be found in:
•
microwave oven (what do these measure?),
•
regular ovens (what do these measure?),
•
many systems in a car (consider the engine speed, car speed, oil pressure, coolant temperature, fuel,
. . . ),
•
an orchestra, rock band or jazz band (explain this one if you want a bit of a challenge; what is
measured, and by whom?),
•
your class (another neat one to explain; again, what is measured, and by whom?),
•
a cell phone (look at it carefully.
. . ).
3. Question 1.3
4. Question 1.8
5. Question 1.9
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