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3D153 V1 - U4 SS
Radio Frequency Test Equipment
58
Communication
Professional
02/28/2012

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Term
026-1. What is the frequency range of the HP 8640B RF signal generator?
Definition
500 kHz to 512 MHz (450 kHz to 550 MHz with over-range).
Term
026-2. What extends the HP 8640B range from 20 Hz to ultra high frequencies?
Definition
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.
Term
026-3. What is the function of the oscillator section?
Definition
To produce a signal that can be set accurately in frequency at any point within the range of the generator.
Term
026-4. What is the function of the modulator?
Definition
To produce an audio modulating signal to superimpose on the radio frequency signal produced in the oscillator.
Term
026-5. What types of modulated signals are possible with the radio frequency generator?
Definition
Either sine waves, square waves, or pulses of varying duration.
Term
026-6. What does the output circuit of the radio frequency signal generator usually contain, and what are their functions?
Definition
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.
Term
026-7. List some applications of the radio frequency generator.
Definition
(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.
Term
027-1. The decibel is part of what larger unit of measure?
Definition
Bel
Term
027-2. A power ratio of 10,000:1 can be represented by how many bels?
Definition
Four
Term
027-3. What’s the most commonly used industry standard power reference level?
Definition
The 1-milliwatt standard.
Term
027-4. How is the answer to question number 3 expressed?
Definition
As decibels referenced to a 1-milliwatt standard or dBm
Term
027-5. 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.
Definition
(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.
Term
027-6. What will every 3 dB increase in gain do to the power level?
Definition
Roughly double it.
Term
027-7. How many dB of gain does an amplifier have if there are 10 watts in and 80 watts out?
Definition
There’s a gain of 9dB.
Term
027-8. 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?
Definition
It will cut it in half.
Term
027-9. What two power characteristics are reflected by the term dBm?
Definition
(1) Gain level.
(2) Power level.
Term
027-10. How do the terms dB and dBm differ?
Definition
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.
Term
027-11. How much more power is available at 6 dBm than at 3 dBm?
Definition
Twice as much
Term
027-12. What power levels are indicated by these measurements?
(a) 3 dBm.
(b) 9 dBm.
(c) 12 dBm.
(d) 36 dBm.
Definition

(a) 2 mW.
(b) 8 mW.
(c) 16 mW.

(d) 4,096 mW (approx 4.1 watts).

Term
028-1. List at least three of the units that can be displayed by the HP 436A power meter.
Definition
(1) Watts.
(2) Milliwatts.
(3) Microwatts.
(4) Nanowatts.
(5) dBm.
(6) Relative dB.
Term
028-2. Briefly explain how to use the relative power measurement mode for frequency response testing.
Definition
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.
Term
028-3. Match the power meter characteristics in column A with the HP 436A features in column B. Each feature in column B can be used once, more than once, or not at all.
Column A
____ (1) For receiving commands from a computer.
____ (2) Determines the frequency range.
____ (3) Ideal for monitoring peaking power.
____ (4) Provides hands free operation.
____ (5) Press SENSOR ZERO to activate.
____ (6) Can be used to stabilize the power source.
____ (7) Determines power measurement range.
____ (8) Provides a stable 1.00mW, 50 MHz output
____ (9) Output can be used to print graphs.
Column B
a. Auxiliary meter.
b. Power sensor.
c. Autorange.
d. Auto zero.
e. Recorder output.
f. Interface connector.
g. Calibrator output.
h. RF blanking output.
Definition
(1) f.
(2) b.
(3) a.
(4) c.
(5) d.
(6) e.
(7) b.
(8) g.
(9) e.
Term
029-1. What is the 4391M RF Power Analyst designed to measure?
Definition
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.
Term
029-2. What are the two switches on the front panel of the instrument used for?
Definition
Two switches on the front panel of the instrument are set by the user to correspond to the power range of the forward element.
Term
029-3. If only the forward element is used, what is filled in the other socket?
Definition
If only one element is used, the other socket should be filled with a dust plug or a higher power element.
Term
029-4. Why are the elements clamped into place by the hold-down catches on the face of the line section?
Definition
These catches must be used to avoid error due to the element not contacting the bottom or seating plane of the socket.
Term
029-5. When powered up, which mode is the 4391M wattmeter always goes into?
Definition
When powered up, the 4391M wattmeter always goes into the forward CW power mode.
Term
029-6. When reading forward power, what will be displayed if the applied power exceeds 120 percent of the range?
Definition
If the applied power exceeds 120 percent of the range, two right facing arrow heads will be displayed.
Term
029-7. Where is the reflected CW reading taken?
Definition
Readings are taken from the element in the socket marked “reflected.”
Term
029-8. Between what power ranges will a SWR be displayed?
Definition
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.
Term
029-9. What is the difference between the readings CW and PEP?
Definition
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.
Term
029-10. How is over-modulation displayed on the wattmeter?
Definition
Over-modulation will be indicated as 99.9 percent.
Term
029-11. What must be added to the dBm reading when the range is in kilowatts?
Definition
30 must be added to all dBm readings when the range is in kilowatts.
Term
029-12. When measuring return loss, what does a reading of 21.6 indicates?
Definition
The measurement of return loss reading of 21.6 indicates that reflected power is 21.6 dB down from forward power.
Term
029-13. In order to recall the maximum reading, what key do you press?
Definition
To recall the maximum reading, hold the MAX or MIN key down.
Term
029-14. How do you clear the minimum and maximum register?
Definition
To clear the minimum and maximum register, the mode key must be pressed again or a new selected.
Term
029-15. Which mode is useful for making adjustments to optimize any of the parameters which the wattmeter measures?
Definition
Peaking aid.
Term
030-1. What is a major difference between the oscilloscope and the spectrum analyzer?
Definition
The oscilloscope displays frequency information in the time domain, whereas the spectrum analyzer displays frequency information in the frequency domain.
Term
030-2. Describe how the spectrum analyzer displays information in the frequency domain.
Definition
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.
Term
030-3. What functions does the spectrum analyzer perform?
Definition

(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.

Term
030-4. What advantage do the spectrum analyzer’s sensitivity and wide dynamic range provide?
Definition
A way to measure low-level modulation.
Term
030-5. List some uses of the spectrum analyzer.
Definition
(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.
Term
031-1. What is the frequency range of an electronic frequency counter?
Definition
Low audio frequencies up to 550 MHz. Some methods are available to extend the frequency range of counters to more than 20 GHz.
Term
031-2. Match the description in column B with the correct function in column A. Items can only be used once.
Column A
___(1) Measurement totals number of input cycles over a period of time.
___(2) The average bit-to-bit time of the input signal in a digital system.
___(3) Measures the time between two points of a common event.
___(4) Provides a divided version of the input frequency.
___(5) Counts the number of bits in a pulse train.
___(6) Measures harmonically related signals.
Column B
a. Ratio.
b. Period.
c. Scaling.
d. Totalize.
e. Frequency.
f. Time interval.
Definition
(1) e.
(2) b.
(3) f.
(4) c.
(5) d.
(6) a.
Term
031-3. What provides the time reference for the precise timing and where does this function take place?
Definition
A quartz-crystal oscillator inside the counter.
Term
032-1. What is a CSM?
Definition
The CSM is a microprocessor controlled, digitally synthesized test set which combines the operations of many different test instruments into a single, compact unit.
Term
032-2. How are meters on the major operations screens displayed?
Definition
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.
Term
032-3. What part of the CSM edits the operation screens to reflect changes in parameters imposed by the operator?
Definition
Microprocessor
Term
032-4. How can the meter operation screens be accessed?
Definition
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.
Term
032-5. When a specific mode of operation is selected, what operational parameters appear on the screen?
Definition
Once a specific mode of operation is selected, the parameters shown reflect the parameters last entered in that operation.
Term
32-6. Which screens can operator entry and edit of data is performed?
Definition
Operator entry and edit of data is performed on the operation screen or on the setup menu.
Term
32-7. Once the parameter is accessed, how is data selected?
Definition
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.
Term
32-8. What is a multi-task soft function keys?
Definition
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.
Term
32-9. How many system configurations can the user store?
Definition
Allows the user to store and recall up to nine system configurations.
Term
32-10. 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?
Definition
100
Term
32-11. Name several function or operation of the communication service monitor?
Definition
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.
Term
33-1. Which receiver access input point would you use for higher-powered signals?
Definition
T/R connector
Term
33-2. Match the type of operation in column B with the capability in column A. Items can only be used once.
Column A
___ (1) Includes square, triangle, or ramp waveform.
___ (2) View demodulated audio.
___ (3) Generates modulation type output level between –137 to 0 dBm.
___ (4) Receives AM, FM, PM and SSB modulated signals.
___ (5) Monitors transmit and receive test.
___ (6) Has zero scan capability.
Column B
a. Receiver.
b. Generator.
c. Duplex.
d. Function generator.
e. Spectrum analyzer.
f. Scope.
Definition
(1) d.
(2) f.
(3) b.
(4) a.
(5) c.
(6) e.
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