3D1X3 Self Test Questions Vol. 1 Unit 4

Front 1

What is the frequency range of the HP 8640B RF signal generator?

Back 1

500 kHz to 512 MHz (450 kHz to 550 MHz with over-range).

Front 2

What extends the HP 8640B range from 20 Hz to ultra high frequencies?

Back 2

A variable audio oscillator can extend the output range of the generator down to 20 Hz and a doubler can
extend it to 11,000 MHz. This, together with a calibrated output and modulation, permits complete radio
frequency and intermediate frequency performance tests on virtually any type of high frequency, very high
frequency, or ultra high frequency receiver.

Front 3

What is the function of the oscillator section?

Back 3

To produce a signal that can be set accurately in frequency at any point within the range of the generator.

Front 4

What is the function of the modulator?

Back 4

To produce an audio modulating signal to superimpose on the radio frequency signal produced in the
oscillator

Front 5

What types of modulated signals are possible with the radio frequency generator?

Back 5

Either sine waves, square waves, or pulses of varying duration.

Front 6

What does the output circuit of the radio frequency signal generator usually contain, and what are
their functions?

Back 6

A calibrated attenuator and an output level meter. The attenuator lets you select the amount of output
required. The output level meter provides an indication and permits control of the generator output voltage.

Front 7

List some applications of the radio frequency generator.

Back 7

(1) Verify transmission within designated frequency ranges by comparing transmitter outputs with known
radio frequencies.
(2) Align a receiver by injecting the system with range-standard modulated radio frequency.
(3) Check transmission lines and antenna systems for proper operation.

Front 8

The decibel is part of what larger unit of measure?

Back 8

Bel.

Front 9

A power ratio of 10,000:1 can be represented by how many bels?

Back 9

Four.

Front 10

What’s the most commonly used industry standard power reference level?

Back 10

The 1-milliwatt standard.

Front 11

How is the answer to question number 3 expressed?

Back 11

As decibels referenced to a 1-milliwatt standard or dBm.

Front 12

Rewrite these sentences so they use the term dB correctly.
(a) This TWT has 25 dB of output power.
(b) The final amp is pumping out a 30 dB package.

Back 12

(a) This TWT has a power gain of 25 dB.
(b) The final amp is pumping out a package that’s 30 dB more than its input.

Front 13

What will every 3 dB increase in gain do to the power level?

Back 13

Roughly double it.

Front 14

How many dB of gain does an amplifier have if there are 10 watts in and 80 watts out?

Back 14

There’s a gain of 9dB.

Front 15

You have installed an in-line 3 dB attenuator between a power source and the power sensor of a
power meter. How will this affect the power level displayed by the power meter?

Back 15

It will cut it in half.

Front 16

What two power characteristics are reflected by the term dBm?

Back 16

(1) Gain level.
(2) Power level.

Front 17

How do the terms dB and dBm differ?

Back 17

Because dBm is always referenced to a 1-milliwatt standard, it can be used to reflect a power level, in
addition to gain or loss. The term dB can’t reflect a power level; instead, it can only reflect gain or loss
because it’s purely a ratio.

Front 18

How much more power is available at 6 dBm than at 3 dBm?

Back 18

Twice as much.

Front 19

What power levels are indicated by these measurements?
(a) 3 dBm.
(b) 9 dBm.
(c) 12 dBm.
(d) 36 dBm.

Back 19

(a) 2 mW.
(b) 8 mW.
(c) 16 mW.
(d) 4,096 mW (approx 4.1 watts).

Front 20

List at least three of the units that can be displayed by the HP 436A power meter.

Back 20

(1) Watts.
(2) Milliwatts.
(3) Microwatts.
(4) Nanowatts.
(5) dBm.
(6) Relative dB.

Front 21

Briefly explain how to use the relative power measurement mode for frequency response testing.

Back 21

After the input is connected, press dB(REF) to lock in this frequency level as the reference, then tune the
transmitter to other frequencies and observe any changes up or down in the power level.

Front 22

What is the 4391M RF Power Analyst designed to measure?

Back 22

The 4391M RF Power Analyst is an RF Directional Thruline Wattmeter designed to measure power flow,
load match, and AM in 50 ohm coaxial transmission lines.

Front 23

What are the two switches on the front panel of the instrument used for?

Back 23

Two switches on the front panel of the instrument are set by the user to correspond to the power range of
the forward element.

Front 24

If only the forward element is used, what is filled in the other socket?

Back 24

If only one element is used, the other socket should be filled with a dust plug or a higher power element.

Front 25

Why are the elements clamped into place by the hold-down catches on the face of the line
section?

Back 25

These catches must be used to avoid error due to the element not contacting the bottom or seating plane of
the socket.

Front 26

When powered up, which mode is the 4391M wattmeter always goes into?

Back 26

When powered up, the 4391M wattmeter always goes into the forward CW power mode.

Front 27

When reading forward power, what will be displayed if the applied power exceeds 120 percent of
the range?

Back 27

If the applied power exceeds 120 percent of the range, two right facing arrow heads will be displayed.

Front 28

Where is the reflected CW reading taken?

Back 28

Readings are taken from the element in the socket marked “reflected.”

Front 29

Between what power ranges will a SWR be displayed?

Back 29

SWR will be displayed if the average forward power is between 10 percent and 120 percent of the full scale
and the average reflected power is less than 120 percent of the reflected element range.

Front 30

What is the difference between the readings CW and PEP?

Back 30

Readings are displayed directly as peak power in PEP. To formulate CW power, the wattmeter measures
peak and minimum square root of power and combines them.

Front 31

How is over-modulation displayed on the wattmeter?

Back 31

Over-modulation will be indicated as 99.9 percent.

Front 32

What must be added to the dBm reading when the range is in kilowatts?

Back 32

30 must be added to all dBm readings when the range is in kilowatts.

Front 33

When measuring return loss, what does a reading of 21.6 indicates?

Back 33

The measurement of return loss reading of 21.6 indicates that reflected power is 21.6 dB down from
forward power.

Front 34

In order to recall the maximum reading, what key do you press?

Back 34

To recall the maximum reading, hold the MAX or MIN key down.

Front 35

How do you clear the minimum and maximum register?

Back 35

To clear the minimum and maximum register, the mode key must be pressed again or a new selected.

Front 36

Which mode is useful for making adjustments to optimize any of the parameters which the
wattmeter measures?

Back 36

Peaking aid.

Front 37

What is a major difference between the oscilloscope and the spectrum analyzer?

Back 37

The oscilloscope displays frequency information in the time domain, whereas the spectrum analyzer
displays frequency information in the frequency domain.

Front 38

Describe how the spectrum analyzer displays information in the frequency domain.

Back 38

By complex signals (i.e., signals composed of more than one frequency) that are separated into their
frequency components, and the power level of each frequency is displayed.

Front 39

What functions does the spectrum analyzer perform?

Back 39

(1) Locate and identify signals over a wide frequency spectrum.
(2) Magnify parts of the spectrum for detailed analysis with stable, calibrated sweeps and resolution.
(3) Minimize display clutter for spurious responses within itself.
(4) Furnish wide dynamic range and flat frequency response.

Front 40

What advantage do the spectrum analyzer’s sensitivity and wide dynamic range provide?

Back 40

A way to measure low-level modulation.

Front 41

List some uses of the spectrum analyzer.

Back 41

(1) Measure AM, FM, and pulsed radio frequency.
(2) Measure long- and short-term frequency stability.
(3) Measure parameters such as subcarrier oscillator outputs, channels of complex signals.
(4) Measure frequency drift during system warm-up.

Front 42

What is the frequency range of an electronic frequency counter?

Back 42

Low audio frequencies up to 550 MHz. Some methods are available to extend the frequency range of
counters to more than 20 GHz.

Front 43

What provides the time reference for the precise timing and where does this function take place?

Back 43

A quartz-crystal oscillator inside the counter.

Front 44

What is a CSM?

Back 44

The CSM is a microprocessor controlled, digitally synthesized test set which combines the operations of
many different test instruments into a single, compact unit.

Front 45

How are meters on the major operations screens displayed?

Back 45

On the major operations screens, these meters display as bar graph display and digital data or just as digital
data, depending on the oscilloscope/spectrum analyzer display size.

Front 46

What part of the CSM edits the operation screens to reflect changes in parameters imposed by the
operator?

Back 46

Microprocessor.

Front 47

How can the meter operation screens be accessed?

Back 47

The meter operation screens can be accessed through the mode operation screen that is being supported by
that specific meter operation or through the meter menu.

Front 48

When a specific mode of operation is selected, what operational parameters appear on the screen?

Back 48

Once a specific mode of operation is selected, the parameters shown reflect the parameters last entered in
that operation.

Front 49

Which screens can operator entry and edit of data is performed?

Back 49

Operator entry and edit of data is performed on the operation screen or on the setup menu.

Front 50

Once the parameter is accessed, how is data selected?

Back 50

Once the parameter is accessed, data can be selected with DATA SCROLL spinner or DATA SCROLL
keys or by using the alphanumeric DATA ENTRY keypad.

Front 51

What is a multi-task soft function keys?

Back 51

Multi-task “soft” function keys perform set up, edit and entry. Each operation screen defines soft function
keys to fit the specific needs for that operation.

Front 52

How many system configurations can the user store?

Back 52

Allows the user to store and recall up to nine system configurations.

Front 53

How many frequencies are allowed to be stored into a list for use when performing tasks that
require the same instrument setup to be utilized on many different frequencies?

Back 53

100.

Front 54

Name several function or operation of the communication service monitor?

Back 54

RF generator, AF generator, oscilloscope, deviation (peak) meter, SINAD meter, frequency error meter,
modulation meter, bit error rate meter, deviation (RMS) meter, cable fault detector, receiver, spectrum
analyzer, digital multimeter, distortion meter, AF meter, RF power meter, signal strength meter, phase
meter, and tracking generator.

Front 55

Which receiver access input point would you use for higher-powered signals?

Back 55

T/R connector.