Test & Measurement Challenges: Answers and Winners, 2010

Here are the answers to Test & Measurement Challenges that concluded in 2010. The answers are presented in chronological order, with the most recent challenge appearing first. Back to the main Challenge Page.

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Instrumentation Challenge: Oscilloscope Eye Diagrams, September 2010

Question
Eye diagrams make it possible to characterize the jitter that is present on serial-bus digital signals.
Which of the following statements best describes the relationship of an oscilloscope to an eye diagram?

a) The eye diagram is a frequency-domain representation and cannot be displayed by an oscilloscope.
b) The eye diagram is a frequency-domain representation that you can obtain by performing a fast Fourier transform (FFT) on data captured by a digital storage oscilloscope.
c) An oscilloscope can display an eye diagram directly.

Answer
The correct answer is c.

Winner
The winner of the $100 American Express gift check, courtesy of Test & Measurement World, is James Migliaccio, Greensboro, NC.

 

Data-Acquisition Challenge: Triggering

Question
Which statement accurately describes data-acquisition-system triggering? (Choose the best answer.)

a) In a post-triggered acquisition, such as a crash test, a trigger event occurs and then the system collects the data you want.
b) A pretriggered acquisition can collect data before and after a trigger event occurs.
c) Statements a and b are both true.
d) Neither statement a nor statement b is true.

Answer
The correct answer is c.

Winner
The winner of the $100 American Express gift check, courtesy of Test & Measurement World, is Tom Wehn, Mayfield, OH.

Instrumentation Challenge: Oscilloscope X-Y Mode

Question
Why might you employ an oscilloscope's x-y mode? (Choose the best answer.)

a. To display voltage vs. time.
b. To display Lissajous patterns that indicate two waveforms' phase differences.
c. To generate I-V curves.
d. All of the above.
e. None of the above.
f. Statements a and b.
g. Statements b and c.
h. Statements a and c.

Answer
The correct answer is g.

Winner
The winner of the $100 American Express gift check, courtesy of Test & Measurement World, is Jeff Pegram, Richmond, VA.

Communications Challenge: RF Signal Analyzers

Question
Which of the following contributes to an RF signal analyzer's dynamic range? (Choose the best answer.)

a) Third-order intercept level. 
b) Displayed average noise level. 
c) Phase-noise performance. 
d) All of the above. 
e) Statements a and b. 
f) Statements b and c. 
g) Statements a and c.

Answer
The correct answer is d.

Winner
The winner of the $100 American Express gift check, courtesy of Test & Measurement World, is Eric Hakanson, Morgan Hill, CA.

 

Data-Acquisition Challenge: ENOB, August 2 to September 6, 2010

Question
Which of the following degrades a measurement system's ENOB (effective number of bits)? (Choose the best answer.)

a) Noise from gain-setting resistors within the instrumentation amplifier
b) Sample-and-hold amplifier bandwidth errors
c) Channel-to-channel offset
d) Input multiplexer channel crosstalk
e) Nonlinearity of an analog-to-digital converter
f) All of the above
g) Answers a and d only

Answer
The correct answer is f.

Winner
The winner of the 6GB iPad,courtesy of Data Translation (the contest sponsor), is Chris Brenizer, Jefferson City, MO.

LTE Challenge, March 1 to March 31, 2010

Question
Which of the following is an uplink pilot signal used in LTE?

a) Demodulation reference signal: This signal is sent by the user terminal along with the uplink transmission; it assists the network in estimating the channel impulse response for the uplink bursts so as to effectively demodulate the uplink channel.

b) Uplink reference signal: This signal is sent by the user terminal; it assists the network in determining the location of the mobile and determining the channel resources to be allocated.

c) Demodulation sounding signal: This signal is sent by the user terminal; it assists the network in estimating the channel impulse response for the uplink bursts so as to effectively assign subcarriers.

d) Uplink reference signal: This signal is sent by the user terminal along with the uplink transmission; it assists the network in estimating the frequency response of the channel and ensures that the correct subcarriers are assigned.

Answer:
The correct answer is a.

Winner:
The winner of the Amazon Kindle, courtesy of Anritsu (the contest sponsor), is Mark Bushnell, Garland, TX.

Instrumentation Challenge: Interfaces (January 25 through February 22, 2010)

Question
How many pins are on a GPIB connector?

a) 37
b) 10
c) 25
d) 24
e) 9

Answer: The correct answer is d.

Winner: The winner of the $100 American Express gift check (courtesy of Test & Measurement World) is Donald Peate, Columbia, MD.

Instrumentation Challenge: Ethernet (January 19 through February 16, 2010)

Question
Which is the IEEE standard for 100-Gbps Ethernet?

a) 802.11n
b) 802.11g
c) 802.3ba
d) 802.3az
e) 802.3aj

Answer: The correct answer is c.

Winner: The winner of the $100 American Express gift check (courtesy of Test & Measurement World) is Brian Boeshans, Carrington, ND.

Compliance Challenge: Anechoic Chambers (January 11 through February 8, 2010)

Question
Why are anechoic chambers used for EMI (electromagnetic interference) testing typically lined with cones?

a) The cones minimize reflections by absorbing radiated emissions above 1 GHz.
b) The cones shield outside signals from entering the chamber.
c) The cones reflect signals above 1 GHz.
d) The cones reduce the usable area inside the chamber.
e) The cones provide a uniform temperature inside the chamber.

Answer: The correct answer is a.

Winner: The winner of the $100 American Express gift check (courtesy of Test & Measurement World) is Patrick D Nee, Salt Rock, WV.

 

Instrumentation Challenge: Thermocouples (January 4 through February 1, 2010)

Question
Which type of thermocouple cannot be used below 0°C?

a) Type N
b) Type K
c) Type T
d) Type E
e) Type J

Answer: We inadvertently omitted the correct answer from the list of choices—all of the thermocouples work below 0°C. Because of this, everyone who submitted an answer and complied with the eligibility guidelines was eligible for the prize.

Winner: The winner of the $100 American Express gift check (courtesy of Test & Measurement World) is Clark Stremke, Waukesha, WI.

Programming Language Challenge: Syntax (December 17, 2009, through January 13, 2010)

Question
The command string "MEAS:VOLT:DC" is an example of what syntax?

a) VISA
b) SCPI
c) Visual Basic
d) Tcl
e) C++

Answer: The correct answer is b.

Winner: The winner of the $100 American Express gift check (courtesy of Test & Measurement World) is Allan Rosenzweig, Brooklyn, NY.



Oscilloscope Challenge: Bandwidth (December 8, 2009, through January 5, 2010)

Question
You need to make a measurement and you know your signal's 10% to 90% rise time. What is the minimum oscilloscope analog front-end bandwidth required?

a) Bandwidth = 1 divided by the maximum rise time of the signal you want to measure.
b) Bandwidth = 1 divided by the minimum rise time of the signal you want to measure.
c) Bandwidth = 0.35 divided by the maximum rise time of the signal you want to measure.
d) Bandwidth = 0.35 divided by the minimum rise time of the signal you want to measure.

Answer: The correct answer is d.

Winner: The winner of the $100 American Express gift check (courtesy of Test & Measurement World) is Dan Fettner, Poway, CA.