3D1X3 Self Test Questions Vol. 1 Unit 3

Front 1

Which control do you use to select the meter’s different measurement functions?

Back 1

The rotary switch.

Front 2

List the four types of information presented in the multimeter’s display section.

Back 2

(1) Digital display.
(2) Visual annunciators.
(3) Analog bar graph.
(4) Range indicator.

Front 3

Which information in the display section shows the absolute value of the input?

Back 3

Analog bar graph.

Front 4

Describe the function of the range push button.

Back 4

Lets you manually select the measurement range.

Front 5

What is the purpose of the touch-hold push button?

Back 5

Locks the measurement into the display for viewing and automatically updates the display when you take a
new measurement.

Front 6

List the multimeter’s four input jacks.

Back 6

(1) Amperes.
(2) Milliamps/microamps.
(3) Volts/ohms/diode.
(4) Common.

Front 7

When does the 8025A perform a power-up self test?

Back 7

When you move the rotary switch to any position from the OFF position.

Front 8

What two ranges of DC voltages can you measure using the 8025A multimeter?

Back 8

(1) −1,000 to +1,000 volts DC.
(2) −320 to +320 millivolts DC.

Front 9

What is the maximum amount of continuous AC current that you can measure with the
multimeter?

Back 9

10 amps.

Front 10

When using the Fluke 8025A, how do you know you’re in the resistance measurement function?

Back 10

The Ω annunciator is showing in the display.

Front 11

How do you determine if you’re testing a “good” diode with the 8025A?

Back 11

Placing the leads across a “good” diode produces “OL” in the display while reversing the leads produces a
continuous audible tone.

Front 12

What type of display does the oscilloscope present?

Back 12

Amplitude vs. time.

Front 13

On which axis of an oscilloscope is voltage, time, and depth information presented?

Back 13

Voltage = vertical axis, time = horizontal axis, and depth = intensity.

Front 14

What is the purpose of the delay line at the input of the vertical amplifier?

Back 14

It allows the sweep generator circuitry time to start a sweep before the signal reaches the cathode ray tube
vertical deflection plates. This enables you to view the leading edge of the signal waveform.

Front 15

What position of the input coupling switch is used to view digital-type or square wave signals?

Back 15

DC coupling.

Front 16

What is the basic purpose of the oscilloscope probe?

Back 16

To provide isolation for scope inputs and prevent circuit loading.

Front 17

List four types of probes?

Back 17

(1) The high resistance.
(2) Passive divider and x1 probes.
(3) Active (field effect transistor).
(4) Current probes.

Front 18

What is the typical input impedance of most oscilloscopes?

Back 18

One megaohm shunted by 20 pF of capacitance.

Front 19

When making an amplitude measurement and the source impedance is unknown, greatest
accuracy is achieved when the probe’s Z is what?

Back 19

Highest (maximum).

Front 20

What is the biggest difference between digital storage oscilloscopes and analog scopes?

Back 20

Digital storage oscilloscopes digitize the input signal for storage or display.

Front 21

What is the function of charged coupled devices in the digital storage oscilloscope’s signal
sampling process?

Back 21

Charged coupled devices accept fast-changing data and send it to the analog-to-digital-converter at a slower
rate for more accurate data collection.

Front 22

Define the following waveform storage terms:
a) Waveform points.
b) Waveform record.
c) Record length.

Back 22

(a) Sampled data points stored in the digital storage oscilloscopes memory.
(b) Stored waveform points that make up the waveform record.
(c) Number of waveform points used to make the waveform record.

Front 23

What advantage does retrieving data from memory have on the cathode ray tube?

Back 23

It allows the cathode ray tube to receive data at a slower rate as opposed to keeping up with some of the
high frequency signals fired directly on a cathode ray tube in an analog scope.

Front 24

List two digital storage oscilloscope sampling techniques.

Back 24

(1) Real-time.
(2) Repetitive-sampling.

Front 25

Define interpolation.

Back 25

This is a process that estimates what the signal will look like between samples and “fills in the blanks”
between data points.

Front 26

What are the two types of interpolation?

Back 26

(1) Linear.
(2) Sine.

Front 27

What is the difference between sequential and random sampling?

Back 27

Sequential sampling takes a sample at a predetermined time after the trigger in a progressive order until
there are enough data points to reconstruct several periods of the signal. Random sampling takes samples at
an undetermined point on a signal and stores them.

Front 28

What is a common cause of aliasing?

Back 28

Undersampling due to having the time base turned down too low, thus reducing the sample rate for a
frequency that is too high for a given setting.

Front 29

Describe the three types of acquisition modes.

Back 29

(1) In sample mode, the digital storage oscilloscope creates a record point by saving the first sample in a
collection of sample points.
(2) In peak detect mode, the digital storage oscilloscope saves the highest and lowest points in a
collection of samples.
(3) In averaging mode, the digital storage oscilloscope shows a record that is a collection of several
acquisitions of a repeated signal that is averaged over time.

Front 30

What is the function of the acquisition controls?

Back 30

To set the digital storage oscilloscope’s sampling rate, determine what type of processing will occur and
how many record points can be shown.

Front 31

What is the range of record points that the Tektronix 2230 digital storage oscilloscope can
acquire?

Back 31

1,000 (1K) to 4,000 (4K) points.

Front 32

Which control sets up acquisition either before a trigger or at the beginning of a waveform?

Back 32

PRETRIG/POST TRIG switch.

Front 33

What happens to the NORM and P-P AUTO trigger modes while in ROLL mode?

Back 33

These triggers are disabled allowing the digital storage oscilloscope to continuously acquire and display
incoming signals.

Front 34

In the NORM trigger mode, how are the pretrigger waveform and post trigger scan updated?

Back 34

By the trigger and post trigger scan from the trigger position to the right.

Front 35

In the SAVE mode, what happens to the acquisition and display update in progress?

Back 35

It stops.

Front 36

What types of measurements in the STORE mode are made with CURSORS controls?

Back 36

Delta volts, delta time, one over delta time, and delay time measurements.

Front 37

Which switch establishes the function of the CURSORS position control?

Back 37

POSITION/CURS/SELECT WAVEFORM switch.

Front 38

Explain how a 4K record length is shown on the display.

Back 38

A 4-bar graph on the screen indicates which portion of the record you are viewing. A 4K record length
displays 1K samples at a time. You have to look at four different screens to see the entire record length.

Front 39

In the SELECT WAVEFORM mode using the SELECT C1/C2 (cursor-select) switch, what
happens when the C1/C2 switch is pressed?

Back 39

It moves the cursor set between displayed waveforms.

Front 40

What is the purpose of the MEMORY and menu controls?

Back 40

They control the MENU operation while the MENU is displayed, and they control the storage and display
of the SAVE reference waveforms when the MENU is not displayed.

Front 41

What is the purpose of the BERTS?

Back 41

To provide a bit error detection system that can determine the received data quality.

Front 42

What type of test can the BERTS perform?

Back 42

Bit error analysis, timing analysis, or delay measurements. Also the BERTS is a source of PCM data used
to test a communications data link or a bit synchronizer output. Many BERT can generate command test
patterns, telemetry PCM formats, and bit coding patterns at telemetry data rates.

Front 43

What is the purpose of the internal clock generator?

Back 43

To provide an internal clock reference—usually selectable from the front panel.

Front 44

What is the purpose of the voltage controlled oscillator, and how is it calibrated?

Back 44

As the basic clock generator, it provides all clock phases. It is periodically frequency calibrated by a
crystal-controlled oscillator in the AUTO-CAL section.

Front 45

What is the purpose of the countdown section of the internal clock generator?

Back 45

To divide the voltage controlled oscillator clock and provide a frequency equal to the bit rate selected.

Front 46

What is the purpose of the digital-to-analog converter and the decode range splitter, and for what
purpose does this section use the binary coded decimal information?

Back 46

To use the binary coded decimal information to control the voltage controlled oscillator center frequency,
and to control the range the countdown circuits will decode. They use the binary coded decimal information
to control the voltage controlled oscillator center frequency, and to control the range the countdown circuits
will decode.

Front 47

What is the purpose of the pattern simulator?

Back 47

To accept either the external or internal clock and generate either a pseudo-random noise pattern or a 48-bit
pattern you program from the front panel.

Front 48

Which pattern simulator section controls the clock selector and selects either the external clock or
the internal clock for processing?

Back 48

Data/clock selects encoder.

Front 49

What is the purpose of the pseudo random noise generator?

Back 49

To receive the internal clock from the clock selector and generate a 2,047 bit long pseudo-random pattern.

Front 50

What is the purpose of the pseudo random noise blanking generator, and what are the blanking
periods?

Back 50

To provide a blanking period at the start of the 2,047 bit pseudo random noise frame (under the control of
the blanking selector switch). The blanking period can be 0, 32, 64, 96, or 128 bits long.

Front 51

What is the purpose of the 48-bit register and 8-bit word display?

Back 51

To accept six 8-bit words, one word at a time, from the data entry switches and stores them in a 48-bit
register.

Front 52

What controls the data/clock select encoder, and what does it generate?

Back 52

The pattern select and clock select switches; it generates a data select code and a clock select code.

Front 53

Which pattern simulator section selects either pseudo random noise data, external data, or 48-bit
data—depending on which data select code is received?

Back 53

Data/sync selector.

Front 54

What is the purpose of the code converter?

Back 54

To convert the NRZ-L data into the desired coding, such as NRZ-M.

Front 55

What is the purpose of the clock drivers and the data drivers, and where are their outputs sent?

Back 55

The clock drivers convert the selected clock signal to a system compatible level and a buffered TTL level,
and the data drivers convert the encoded data signal to a system compatible level and a buffered TTL level.
The outputs are input to the pattern synchronizer and error counter data/clock receivers block.

Front 56

What is the output from the output amplifier?

Back 56

After mixing the three input signals linearly, it provides a front panel adjustable offset and output level for a
low impedance load.

Front 57

What is the purpose of the pattern synchronizer and error counter?

Back 57

To receive the selected pattern, automatically synchronizes on the pattern, and determine the bit error rate
induced after transmission through the system.

Front 58

What are the inputs to the data/clock receivers?

Back 58

Either system-compatible data or buffered TTL data from the clock drivers and the data.

Front 59

Which pattern synchronizer and error counter sections combine the system compatible and TTL
signals together so only one signal will be present at one time?

Back 59

Data/clock receivers.

Front 60

To what sections are the outputs from the data/clock receivers sent?

Back 60

To the 48-bit synchronizer/comparator, the pseudo random noise synchronizer/comparator, the external
data synchronizer/comparator, and the error rate counter and display sections.

Front 61

What is the purpose of the 48-bit synchronizer/comparator?

Back 61

To accept the received clock and data, and synchronize on the pattern when it’s equal to the 48-bit parallel
input.

Front 62

What is the purpose of the pseudo random noise pattern synchronizer/comparator?

Back 62

To accept the received clock and data, from the data/clock receivers, and will synchronize with the pattern
when it’s equal to its own 2,047 bit pseudo random noise pattern.

Front 63

What is the purpose of the external data pattern synchronizer/comparator?

Back 63

To accept the external data, delay it under the front panel control, and compare it with the received data
from the data/clock receivers.

Front 64

Where does the error/IN SYNC selector send the correct error and IN SYNC signals?

Back 64

To the error rate counter and display.

Front 65

When will the pattern synchronizer and error counter error/IN SYNC section provide an output to
the front panel display, and what will interrupt this output?

Back 65

At the end of the count cycle or when you push the reset switch. A reset pulse will interrupt this output.

Front 66

What is the primary means of measuring the quality of transmitted digital information?

Back 66

To compare the number of bits in error to the total number of bits transmitted. The ratio of the number of
bits in error to total number of bits transmitted.

Front 67

What is the basic quality measurement for a transmission channel?

Back 67

The bit error rate.

Front 68

What is the difference between random distribution of errors and an error rate with a clustered
distribution?

Back 68

In a random distribution, each bit is equally likely to be in error. In a clustered distribution, the errors occur
in clusters.

Front 69

What are the steps in the basic bit error rate testing procedure?

Back 69

(1) A known bit pattern, usually pseudo random, is generated at the sending end of the data channel or
equipment under test, and is transmitted through the channel.
(2) At the receiving end, an identical pattern is generated and synchronized with the incoming signal.
(3) The received signal is compared to the locally generated pattern in the receiving equipment.
(4) If any bit in the received signal is not the same as the generated bit, it is assumed the received bit is in
error.
(5) An error signal is generated and used to operate a counter.

Front 70

Although BERTSs use the same basic technique to count errors, how do you interpret the results
and display information?

Back 70

In many different ways. So, you must use and understand the technical manual for the particular test
equipment.

Front 71

What are some significant bit error rate test equipment parameters?

Back 71

(1) Bit rate and timing.
(2) Test patterns.
(3) Synchronization.
(4) Interface and data coding.
(5) Readouts and special features.

Front 72

How can the BERTS, with internal timing for a low or intermediate bit rate range, be used to
operate at higher bit rates?

Back 72

With external timing.

Front 73

What data circuit speed would normally use the shorter generated bit error rate test pattern
lengths, and what is the data circuit bit rate?

Back 73

Low to intermediate; 1,200 to 9,600 bps.

Front 74

What data circuit speed would normally use the longer pattern lengths, and what is the data
circuit bit rate?

Back 74

Higher speed circuits; 50 kbps to 64 kbps.

Front 75

What data circuit speed would normally use a 1,048,575 bit pattern length, and what is the data
circuit bit rate?

Back 75

Very high speed T–1 circuits; 1.544 Mbps.

Front 76

What bit rate would you use to test a 9,600 bps data circuit?

Back 76

A bit rate of 9,600 bps, or the closet bit rate available, to test the maximum output of the equipment.

Front 77

What bit rate would be used to perform a bit error rate test on a 64 kbps data circuit?

Back 77

64 kbps.

Front 78

What subsection in the receiving section of the BERTS must be synchronized with the received
pattern from either the bit synchronizer or the distant end?

Back 78

The pattern generator.

Front 79

What is one of the major problems encountered in making bit error rate tests?

Back 79

The detection of an “out-of-sync” condition by the test set receiver.

Front 80

What should you know about synchronization in order to interpret the bit error rate test data
correctly?

Back 80

You need to know how test equipment responds to the out-of-sync condition.

Front 81

What type of connectors do test sets, designed to operate with data modems, usually use?

Back 81

25-pin connectors, usually the EIA RS–232 type.

Front 82

What must you check to determine impedance and voltage levels before connecting the BERTS to
the point of test?

Back 82

The technical manuals.

Front 83

What information must be available to you from the BERTS readout or special features?

Back 83

Information to count the number of errors that occur in a specified number of transmitted bits.

Front 84

Why do we test ground?

Back 84

To verify the ground-resistance specification that the ground rod or grid must meet.

Front 85

What test equipment is used to identify poor ground?

Back 85

Earth ground tester.

Front 86

How many points of contacts are used in the Fall of Potential testing method?

Back 86

3.

Front 87

What is each point of contact called in the Fall of Potential testing method?

Back 87

The test ground, voltage probe, and current probe.

Front 88

What distance represents the closest value to the theoretical true resistance measurement?

Back 88

61.8% of the total distance.

Front 89

How is the earth stake placed in the soil?

Back 89

In a direct line away from the earth electrode.

Front 90

Which law is used to calculate the resistance of the earth electrode automatically with the earth
ground tester?

Back 90

Ohm’s Law.

Front 91

Where are the probes placed in order to achieve the highest degree of accuracy?

Back 91

Placed outside the sphere of influence of the ground electrode under test and the auxiliary earth.

Front 92

What is the recommended ground resistance value by the NFPA and IEEE?

Back 92

5 ohms or less.

Front 93

What are the primary capabilities provided by a protocol analyzer?

Back 93

Digital network diagnostics and software development.

Front 94

Explain the difference between a protocol analyzer NIC and other NICs.

Back 94

The NIC in a protocol analyzer is configured to process all frames.

Front 95

What function of the protocol analyzer excludes specific types of frames?

Back 95

Capture filters.

Front 96

List four types of specific occurrences that can be displayed by counters.

Back 96

Any four of the following:
(1) Packets transmitted.
(2) CRC errors.
(3) Undersize packets.
(4) Oversize packets.
(5) ARP requests.
(6) Collisions.
(7) Bit errors.

Front 97

What menu is best used to report errors that occur at the physical layer such as bad FCS, short
frames, and jabbers?

Back 97

MAC node statistics.

Front 98

What kind of information does the connection statistics menu provide?

Back 98

Connection statistics provide information concerning the bandwidth utilization and the number of
connections that are related to specific nodes.

Front 99

Identify the three types of active tests that are conducted with a protocol analyzer.

Back 99

(1) PING.
(2) Trace route.
(3) Traffic generator.