Self Test 220-223

Front 1

220.1 A signal generator is primarily used to troubleshoot what type of circuit?

Back 1

Frequency sensitive or tuned circuit.

Front 2

220.2 What range of frequencies does the audio signal generator provide?

Back 2

From 20hz to 20 Khz

Front 3

220.3 What range of frequuencies does the radio frequency signal generator provide?

Back 3

From 10kHz to 10 GHz

Front 4

220.4 What do you use to match the input impedance of a circuit under test?

Back 4

An attenuator

Front 5

220.5 What are the major components of a basic signal generator?

Back 5

Power supply, one or more oscillators, one or more amplifiers, and an output control.

Front 6

220.6 Why are voltage regulation circuits necessary?

Back 6

To ensure stability of the oscillator in generators deriving power from 115-volt AC sources.

Front 7

220.7 What element of a resistance capacitance oscillator in a commercial signal generator is used as a variable element?

Back 7

Capacitance

Front 8

220.8 How do you conduct a distortion comparison in transmitters and receivers using an audio signal generator?

Back 8

An audio generator can provid a modulation reference signal for a transmitter to send information to a remote receiver. The receiver recovers the transmitted signal (modulation reference) and compares it with the original for any noise distortion.

Front 9

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

Back 9

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

Front 10

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

Back 10

A variable audo oscillator can extend the ouput 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 11

221.3 What is the function of the modulator?

Back 11

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

Front 12

221.4 What is the function of the modulator?

Back 12

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

Front 13

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

Back 13

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

Front 14

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

Back 14

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 ouput voltage.

Front 15

221.7 List some applications of the radio frequency generator.

Back 15

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 16

222.1 What is the output impedance available at the HP 3325B's fron and rear panel output jacks

Back 16

50 ohms

Front 17

222.2 List the output frequency ranges the HP3325B can produce for its different output signal types.

Back 17

Sine wave - 1 MicroHz to 20Mhz
Square waves - 1 MicroHz to 10 Mhz
Triangle and positive/negative Ramps - 1 MicroHz to 10 kHz

Front 18

222.3 Describe the functions of the arrow keys in the Modify keypad.

Back 18

The horizontal arrow keys select the digital to modify, and the vertical arrows increment or decrement the digit.

Front 19

222.4 What internally generated modulating signals can the HP 3325B use to amplitude modulat the main signal?

Back 19

A 10 Khz sine wave or a 2 kHz square wave

Front 20

222.5 What is the HP 3325B's Synch output signal generally used for?

Back 20

Triggering

Front 21

223.1 The decibel is part of what larger unit of measure?

Back 21

Bel

Front 22

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

Back 22

Four

Front 23

223.3 What's the attenuation ratio of a device if the input power is 40 W and the output power is 40 mW?

Back 23

1,000:1

Front 24

223.4 Calculate the output of 40 dB attenuator with a 550 watt input

Back 24

55 mW

Front 25

223.5 Whats the attenuation ratio of the attenuator in question 4?

Back 25

10,000:1

Front 26

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

Back 26

The 1-milliwat standard

Front 27

223.7 How is the answer to # 6 expressed?

Back 27

As decibels referenced to a 1-milliwatt standard or dBm

Front 28

223.8 Rewrite thise sentences so thy 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 28

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 29

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

Back 29

Roughly double it

Front 30

223.10 How many dB of gain does an amplifier have if ther's 10 watts in and 80 watts out?

Back 30

There is a gain of about 9 dB

Front 31

223.11 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 31

It will cut it in half

Front 32

223.12 What two power characteristics are reflected by the term dBm?

Back 32

Gain and power level

Front 33

223.13 How much do the terms dB and dBm differ?

Back 33

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 34

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

Back 34

Twice as much

Front 35

223.15 What power levels are indicated by these measurments?
3dBm
9dBm
12dBm
36dBm

Back 35

a) 2mW, b) 8mW, c) 16mW, d) 4096mW (approx 4.1 watts)

Front 36

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

Back 36

Watts, milliwatts, microwatts, nanowatts, dBm, and relative dB

Front 37

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

Back 37

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

Front 38

225.1 In its broadest sense, what does a power sensor do?

Back 38

Operates as a transducer converting energy from one form into another

Front 39

225.2 Name some of the older power meters.

Back 39

Bolometer, calorimeters, thermistors, and thermocouples.

Front 40

225.3 What are of the advantages of a diode detector over a thermistor mount?

Back 40

Higher sensitivity, reduced noise, less frequency drift, and lower standing wave ratio.

Front 41

225.4 How much more efficient is a detecting diode than a thermistor

Back 41

About 3,000 times

Front 42

225.5 What device dtermines the power measurement range of a power meter?

Back 42

The power sensor

Front 43

225.6 What must you do before you can use the power meter/power sensor system?

Back 43

Calibrate them together as a system

Front 44

225.7 Explain the calibration process.

Back 44

connect the pwer sensor to the POWER REF OUTPUT, press POWER REF ON, and adjust the CAL ADJ until the display reads 1.000mW

Front 45

225.8 Why shouldn't you twist a power sensor when you're installing it?

Back 45

Twisting can damage the sensor's internal circuitry.

Front 46

225.9 What must you use to protect the sensor if the radio frequency source is more powerful than the power can handle?

Back 46

An in-line attenuator

Front 47

225.10 What's a drawback to the power sensor's small size?

Back 47

It's easily dropped, banged, or knocked around

Front 48

225.11 What should you do with a power sensor if it has been dropped?

Back 48

It should be sent to the test equipment calibration lab

Front 49

226.1 What's the basic radio frequency power measurement?

Back 49

Average power

Front 50

226.2 What must you do before turning the HP 436A Power Meter on?

Back 50

Make sure the line voltage setting on the back of the power meter matches the line voltage you're using.

Front 51

226.3 After you've turned on the 436A what's the first task you need to do?

Back 51

Zero the power sensor.

Front 52

226.4 How much radio frequency input is allowed in zeroing the power sensor?

Back 52

None

Front 53

226.5 After you've zeroed the power sensor, what's the next step?

Back 53

Calibrate the power sensor

Front 54

226.6 What power measurement mode must you select to measure average power?

Back 54

Either WATT or dBm.

Front 55

226.7 What's a good use of the relative power measurement technique?

Back 55

Troubleshooting stages of a piece of equipment.

Front 56

226.8 In preparing to make a relative power measurement with the 436:, how do you store the referenced power level for later comparison?

Back 56

By pressing the DB REF switch once.

Front 57

226.9 Once you've stored the reference power level, what should the display read?

Back 57

Zero

Front 58

226.10 What happens when you press the dB REF swich a second time?

Back 58

A new reference power level is stored in the 436A.

Front 59

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

Back 59

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

Front 60

227.2 Describe how the spectrum analyzer displays information in the frequency domain?

Back 60

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

Front 61

227.3 What functions does the spectrum analyzer perform?

Back 61

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.

Front 62

227.3 What funcions does the spectrum analyzer perform?

Back 62

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 63

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

Back 63

A way to measure low level modulation

Front 64

227.5 List some uses of the spectrum analyzer.

Back 64

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 signas
4. Measure frequency drift during system warm up.

Front 65

228.1 What frequency range does the Tektronix 496P spectrum analyzer cover?

Back 65

From 1KHz to 1.8 GHz.

Front 66

228.2 Which trigger control selection is best for general measurements?

Back 66

Free running sweep, unless you need to trigger the sweep, as for pulse modulation measurements or technically directed measurements.

Front 67

228.3 Which spectrum analyzer trigger control selection would you use to display an input signal that is not continuous?

Back 67

Internal (INT)

Front 68

228.4 What spectrum analyzer trigger mode would you use to observe a signal that depends on the occurrence of another signal?

Back 68

External (EXT)

Front 69

228.5 Which spectrum analyzer trigger control lets the sweep be triggered by the AC power source at a rate equal to the frequency of the power source?

Back 69

Line

Front 70

228.6 What sweep control functions just as it does on an oscilloscope adjusting sweep rate.

Back 70

TIME/DIV

Front 71

228.7 Which spectrum analyzer sweep control do you select to run the sweep only once after triggering and must have a READY light indicaiton each time it is run?

Back 71

Single sweep

Front 72

228.8 How is sweep rate determined in MANUAL SCAN?

Back 72

By the rate at which the MANUAL SCAN control is rotated

Front 73

228.9 Which spectrum analyzer sweep control do you select to use an external signal to generate the sweep at a rate determined by the signal amplitude?

Back 73

External (EXT)

Front 74

228.10 Which spectrum analyzer FREQUENCY SCAN/DIV mode do you use to locate signals?

Back 74

Maximum

Front 75

228.11 In the per division mode, which spectrum analyzer FREQUENCY SCAN/DIV control sets the center frequency?

Back 75

FREQUENCY

Front 76

228.12 An analyzer acts like an oscilloscope when the FREQ SPAN/DIV control is in which scan mode?

Back 76

0 Hz

Front 77

228.13 What is the purpose of the spectrum analyzer FREQUENCY control?

Back 77

sets the midpoint (center) of the frequency range for display on the analyzer CRT.

Front 78

228.14 Which spectrum analyzer control selects different frequency bands to be displayed?

Back 78

FREQUENCY RANGE

Front 79

228.15 If you decrease vertical display, i.e., dB/DIV, what is the effect on the vertical display range?

Back 79

Reduces the amplitude.

Front 80

228.16 In which vertical scale is the value of the bottom line on the CRT grid at 0 volts?

Back 80

Linear (LIN)

Front 81

228.17 In which vertical scale is the value of the bottom line on the CRT grid at 0 volts?

Back 81

Logarithmic

Front 82

228.18 Using a spectrum analyzer, what will the signal amplitude be if you're in the LIN (linear) VERTICAL DISPLAY mode, the VERTICAL DISPLAY reads "5.00/mV," and ther is a signal peak six divisions above the CRT bottom line?

Back 82

30 mV

Front 83

228.19 In spectrum analyzers, to what does the term "optimum input level" refer?

Back 83

To the largest input signal that a mixer will accommodate while maintaining ouput distortion products below a given level (specified by the manufacturer). It is usually a negative dB value.

Front 84

228.20 In spectrum analyzers, to wht does the term maximum input level refer?

Back 84

Indicate the damage level of the analyzer front end (mixer and attenuator). Two values are given for maximum input level: the damage level of the mixer and the of the attenuator.

Front 85

228.21 What does a '>' symbol indicate, and what other indication also shows this condition?

Back 85

It indicates an uncalibrated condition. When it's lit, the UNCAL light also indicates that the display amplitude has become "uncalibrated" (inaccurate).

Front 86

228.22 What affect does decreasing the spectrum analyzer TIME/DIV have on sweep rate and the time the intermediate frequency filters have to respond to an input?

Back 86

Increase sweep rat; decreaes intermediate frequency filter response time.

Front 87

228.23 What combinations restores an uncalibrated display on the spectrum analyzer?

Back 87

Increasing the RESOLUTION BANDWIDTH, increasing the TIME/DIV (reducing sweep rate), reducing mixes the SPAN/DIV, and removing video filtering.

Front 88

229.1 What is the frequency range of an electronic frequency counter?

Back 88

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

Front 89

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

Back 89

A quartz-crysat oscillator inside the counter.

Front 90

230.1 How is an electonic frequency counter used in communication-electronics?

Back 90

For verifying transmitter and bit clock frequencies, as well as monitoring frequency modulation drift

Front 91

230.2 What is a primary limitation of an electronic frequency counter?

Back 91

It can't be used directly for receiver calibration, since it's a passive device (only measures) and doesn't produce signals (except for internal use).

Front 92

230.2 What is a primary limitation of an electronic frequency counter?

Back 92

It can't be used directly for receiver calibration, since it's a passive device (only measures) and doesn't produce signals (except for internal use).

Front 93

230.3 What sections are in a frequency counter heterodyne unit?

Back 93

A 1 MHz crystal oscillator, a clipper, and a series of frequency dividing circuits.

Front 94

230.4 What is the advantage of using a Schmitt trigger in the input section of the frequency counter?

Back 94

It produces a very sharp rectangular pulse desite teh shap of the signal at the input

Front 95

230.5 What are the components in a frequency counter time base?

Back 95

A 1 MHz crystal oscillator, a clipper, and a series of frequency dividing circuits.

Front 96

230.6 How is the 1 MHz oscillator kept at a stable frequency?

Back 96

It's maintained in a temperature compensated oven

Front 97

230.7 What are the functions of the gating section?

Back 97

To establish the duration of the counting interval to gate the input signal through to the decimal counting section and to drive the reset circuits, causing the counters to initiate a new cycle of operation.

Front 98

230.8 What units are in the display section?

Back 98

Five decimal counting units connected in cascade.

Front 99

230.9 What is the maximum count the display section counter units will register?

Back 99

99,999 counts derived from the signal being measured.

Front 100

231.1 What kind of cable faults can a time domain reflectometer locate?

Back 100

Splices, water in the cable, split pairs, and discontinuities or faults.

Front 101

231.2 Describe the time domain reflectometer's operating principle.

Back 101

The principle of operation for the time domain reflectometer is similar to that of radar. A pulse from the time domain reflectometer is applied to a cable under test. Any impedance changes in the cable cause a portion of that voltage or energy to be reflected back to the cable input.

Front 102

231.3 Explain how cable fault information appears on the time domain reflectometer's CRT.

Back 102

The CRT displays the pulse's progression from application to the cable on the left hand side of the display to its return at the right. From the display, one can determine the distance down the cable to wher the fault is and the type and severity of the fault.

Front 103

231.4 Explain the purpose of the impedance selector buttons.

Back 103

Used to select the input/output impedance of the time domain reflectometer. You can select 50 ohm, 75 ohm, 95 ohm, and 125 impedances.

Front 104

231.5 Describe how you would connect a cable under test to the time domain reflectometer.

Back 104

Do not connect live circuit cables to the input of the time domain reflectometer. Connect the cable under test to the cable connector on the front panel of the time domain reflectometer.

Front 105

231.6 What do deflections (pips) indicate to the time domain reflectometer user?

Back 105

The key signature factors to remember are upward deflections (pips) indicate high impedance mismatchs or opens and downward deflection (pips) indicate shorts or low impedance mismatches.

Front 106

232.1 Describe the two operating modes used by the TD 9930.

Back 106

REAL-TIME operation, reflections are amplified and displayed directly on the CRT for examination. In the AVG (AVERAGE) mode, the amplified signals are averaged to reduce noise, then stored as digital data.

Front 107

232.3 What are the tests and measurements performed by the optical time domain reflectometer?

Back 107

Cable acceptance testin; cable installation; end to end tests; fault location

Front 108

232.4 What do we call this power that's reflected back?

Back 108

Backscatter

Front 109

232.5 How is the signal loss represented in on optical time domain reflectometer display?

Back 109

The dB drop in backscatter between the two reflections is the signal loss within the fiber.

Front 110

232.6 What index factor is the TD-9930 already programmed to accept?

Back 110

INDEX=1.470