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conditioning devices that can modify or condition a signal include amplifiers, current loops, and
filters, and these were also presented. Because all of these devices are widely used, often in
combination and often masked within more complicated circuits, the reader should strive to become
familiar with the workings of each.
The important issue of loading error was presented. Loading errors, which are due to the act of
measurement or to the presence of a sensor, can only be minimized by proper choice of sensor and
technique. Loading errors that occur between the connecting stages of a measurement system can be
minimized by proper impedance matching. Such impedance matching was discussed, including
using the versatile voltage follower circuit for this purpose.
REFERENCES
1. Hickman, I., Oscilloscopes, 5th ed., Newnes, Oxford, UK, 2000.
2. Bleuler, E., and R. O. Haxby, Methods of Experimental Physics, 2nd ed., Vol. 2, Academic,
New York, NY, 1975.
3. Lacanette, K., A Basic Introduction to Filters: Active, Passive, and Switched-Capacitor
Application Note 779, National Semiconductor, Santa Clara, CA, 1991.
4. Stanley, W. D., G. R. Dougherty, and R. Dougherty, Digital Signal Processing, 2nd ed., Reston
(a Prentice Hall company), Reston, VA, 1984.
5. DeFatta, D. J., J. Lucas, and W. Hodgkiss, Digital Signal Processing, Wiley, New York, 1988.
6. Lam, H. Y., Analog and Digital Filters: Design and Realization, Prentice-Hall, Englewood
Cliffs, NJ, 1979.
7. Niewizdomski, S., Filter Handbook—A Practical Design Guide, CRC Press, Boca Raton, FL, 1989.
8. Bowick, C., C. Ajluni, and J. Blyler, RF Circuit Design, 2nd ed., Newnes, Oxford, UK, 2007.
NOMENCLATURE
c
damping coefficient
e
error
f
frequency (t
-1 )
f c
filter cutoff frequency (t
-1 )
f m
maximum analog signal frequency (t
-1 )
h E i t
ð Þ
f
g function
k
cascaded filter stage order
^
k
unit vector aligned with current flow
l
length (l )
^ n
unit vector normal to current loop
q
charge (C)
r
radius, vector (l )
t
time (t)
u R
uncertainty in resistance R
A
cross-sectional area of a current-carrying
loop; attenuation
A o
operational amplifier open-loop gain
E
voltage (V)
E 1
open circuit potential (V)
E i
input voltage (V)
E m
indicated output voltage (V)
E o
output voltage (V)
F
force mlt
À2
ð
Þ
G
amplifier closed-loop gain
G(s)
transfer function
I
electric current C-t
À1
ð
Þ
I e
effective current C-t
À1
ð
Þ
I g
galvanometer or current device current
C-t
À1
ð
Þ
K
static sensitivity
L
inductance (H)
M( f )
magnitude ratio at frequency f
N
number of turns in a current-carrying loop
R
resistance (V)
R B
effective bridge resistance (V)
R g
galvanometer or detector resistance (V)
Nomenclature 253
11:55:7 Page 253
conditioning devices that can modify or condition a signal include amplifiers, current loops, and
filters, and these were also presented. Because all of these devices are widely used, often in
combination and often masked within more complicated circuits, the reader should strive to become
familiar with the workings of each.
The important issue of loading error was presented. Loading errors, which are due to the act of
measurement or to the presence of a sensor, can only be minimized by proper choice of sensor and
technique. Loading errors that occur between the connecting stages of a measurement system can be
minimized by proper impedance matching. Such impedance matching was discussed, including
using the versatile voltage follower circuit for this purpose.
REFERENCES
1. Hickman, I., Oscilloscopes, 5th ed., Newnes, Oxford, UK, 2000.
2. Bleuler, E., and R. O. Haxby, Methods of Experimental Physics, 2nd ed., Vol. 2, Academic,
New York, NY, 1975.
3. Lacanette, K., A Basic Introduction to Filters: Active, Passive, and Switched-Capacitor
Application Note 779, National Semiconductor, Santa Clara, CA, 1991.
4. Stanley, W. D., G. R. Dougherty, and R. Dougherty, Digital Signal Processing, 2nd ed., Reston
(a Prentice Hall company), Reston, VA, 1984.
5. DeFatta, D. J., J. Lucas, and W. Hodgkiss, Digital Signal Processing, Wiley, New York, 1988.
6. Lam, H. Y., Analog and Digital Filters: Design and Realization, Prentice-Hall, Englewood
Cliffs, NJ, 1979.
7. Niewizdomski, S., Filter Handbook—A Practical Design Guide, CRC Press, Boca Raton, FL, 1989.
8. Bowick, C., C. Ajluni, and J. Blyler, RF Circuit Design, 2nd ed., Newnes, Oxford, UK, 2007.
NOMENCLATURE
c
damping coefficient
e
error
f
frequency (t
-1 )
f c
filter cutoff frequency (t
-1 )
f m
maximum analog signal frequency (t
-1 )
h E i t
ð Þ
f
g function
k
cascaded filter stage order
^
k
unit vector aligned with current flow
l
length (l )
^ n
unit vector normal to current loop
q
charge (C)
r
radius, vector (l )
t
time (t)
u R
uncertainty in resistance R
A
cross-sectional area of a current-carrying
loop; attenuation
A o
operational amplifier open-loop gain
E
voltage (V)
E 1
open circuit potential (V)
E i
input voltage (V)
E m
indicated output voltage (V)
E o
output voltage (V)
F
force mlt
À2
ð
Þ
G
amplifier closed-loop gain
G(s)
transfer function
I
electric current C-t
À1
ð
Þ
I e
effective current C-t
À1
ð
Þ
I g
galvanometer or current device current
C-t
À1
ð
Þ
K
static sensitivity
L
inductance (H)
M( f )
magnitude ratio at frequency f
N
number of turns in a current-carrying loop
R
resistance (V)
R B
effective bridge resistance (V)
R g
galvanometer or detector resistance (V)
Nomenclature 253