1.04 UTF-8 J 0 0 1243588 E8A01 Starting at a positive peak, how many times does a sine wave cross the zero axis in one complete cycle? 0 180 times 0 4 times 0 2 times 1 360 times 0 E8A02 What is a wave called that abruptly changes back and forth between two voltage levels and remains an equal time at each level? 0 A sine wave 0 A cosine wave 0 A square wave 1 A sawtooth wave 0 E8A03 What sine waves added to a fundamental frequency make up a square wave? 0 A sine wave 0.707 times the fundamental frequency 0 All odd and even harmonics 0 All even harmonics 0 All odd harmonics 1 E8A04 What type of wave is made up of a sine wave of a fundamental frequency and all its odd harmonics? 0 A square wave 1 A sine wave 0 A cosine wave 0 A tangent wave 0 E8A05 What is a sawtooth wave? 0 A wave that alternates between two values and spends an equal time at each level 0 A wave with a straight line rise time faster than the fall time (or vice versa) 1 A wave that produces a phase angle tangent to the unit circle 0 A wave whose amplitude at any given instant can be represented by a point on a wheel rotating at a uniform speed 0 E8A06 What type of wave has a rise time significantly faster than the fall time (or vice versa)? 0 A cosine wave 0 A square wave 0 A sawtooth wave 1 A sine wave 0 E8A07 What type of wave is made up of sine waves of a fundamental frequency and all harmonics? 0 A sawtooth wave 1 A square wave 0 A sine wave 0 A cosine wave 0 E8A08 What is the peak voltage at a common household electrical outlet? 0 240 volts 0 170 volts 1 120 volts 0 340 volts 0 E8A09 What is the peak-to-peak voltage at a common household electrical outlet? 0 240 volts 0 120 volts 0 340 volts 1 170 volts 0 E8A10 What is the RMS voltage at a common household electrical power outlet? 0 120-V AC 1 340-V AC 0 85-V AC 0 170-V AC 0 E8A11 What is the RMS value of a 340-volt peak-to-peak pure sine wave? 0 120-V AC 1 170-V AC 0 240-V AC 0 300-V AC 0 E8A12 What is the equivalent to the root-mean-square value of an AC voltage? 0 The AC voltage found by taking the square of the average value of the peak AC voltage 0 The DC voltage causing the same heating in a given resistor as the peak AC voltage 0 The DC voltage causing the same heating in a given resistor as the RMS AC voltage of the same value 1 The AC voltage found by taking the square root of the average AC value 0 E8A13 What would be the most accurate way of measuring the RMS voltage of a complex waveform? 0 By using a grid dip meter 0 By measuring the voltage with a D'Arsonval meter 0 By using an absorption wavemeter 0 By measuring the heating effect in a known resistor 1 E8A14 For many types of voices, what is the approximate ratio of PEP to average power during a modulation peak in a single-sideband phone signal? 0 2.5 to 1 1 25 to 1 0 1 to 1 0 100 to 1 0 E8A15 In a single-sideband phone signal, what determines the PEP-to-average power ratio? 0 The frequency of the modulating signal 0 The speech characteristics 1 The degree of carrier suppression 0 The amplifier power 0 E8A16 What is the approximate DC input power to a Class B RF power amplifier stage in an FM-phone transmitter when the PEP output power is 1500 watts? 0 900 watts 0 1765 watts 0 2500 watts 1 4500 watts 0 E8A17 What is the approximate DC input power to a Class AB RF power amplifier stage in an unmodulated carrier transmitter when the PEP output power is 500 watts? 0 250 watts 0 600 watts 0 1000 watts 1 1500 watts 0 E8A18 What is the period of a wave? 0 The time required to complete one cycle 1 The number of degrees in one cycle 0 The number of zero crossings in one cycle 0 The amplitude of the wave 0 E8B01 What is emission A3C? 0 Facsimile 1 RTTY 0 ATV 0 Slow Scan TV 0 E8B02 What type of emission is produced when an AM transmitter is modulated by a facsimile signal? 0 A3F 0 A3C 1 F3F 0 F3C 0 E8B03 What does a facsimile transmission produce? 0 Tone-modulated telegraphy 0 A pattern of printed characters designed to form a picture 0 Printed pictures by electrical means 1 Moving pictures by electrical means 0 E8B04 What is emission F3F? 0 Modulated CW 0 Facsimile 0 RTTY 0 Television 1 E8B05 What type of emission is produced when an SSB transmitter is modulated by a slow-scan television signal? 0 J3A 0 F3F 0 A3F 0 J3F 1 E8B06 If the first symbol of an ITU emission designator is J, representing a single-sideband, suppressed-carrier signal, what information about the emission is described? 0 The nature of any signal multiplexing 0 The type of modulation of the main carrier 1 The maximum permissible bandwidth 0 The maximum signal level, in decibels 0 E8B07 If the second symbol of an ITU emission designator is 1, representing a single channel containing quantized, or digital information, what information about the emission is described? 0 The maximum transmission rate, in bauds 0 The maximum permissible deviation 0 The nature of signals modulating the main carrier 1 The type of information to be transmitted 0 E8B08 If the third symbol of an ITU emission designator is D, representing data transmission, telemetry or telecommand, what information about the emission is described? 0 The maximum transmission rate, in bauds 0 The maximum permissible deviation 0 The nature of signals modulating the main carrier 0 The type of information to be transmitted 1 E8B10 How does the modulation index of a phase-modulated emission vary with RF carrier frequency (the modulated frequency)? 0 It increases as the RF carrier frequency increases 0 It decreases as the RF carrier frequency increases 0 It varies with the square root of the RF carrier frequency 0 It does not depend on the RF carrier frequency 1 E8B11 In an FM-phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency, what is the modulation index when the modulating frequency is 1000 Hz? 0 3 1 0.3 0 3000 0 1000 0 E8B12 What is the modulation index of an FM-phone transmitter producing a maximum carrier deviation of 6 kHz when modulated with a 2-kHz modulating frequency? 0 6000 0 3 1 2000 0 1/3 0 E8B13 What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 5 kHz and accepting a maximum modulation rate of 3 kHz? 0 60 0 0.167 0 0.6 0 1.67 1 E8B14 In a pulse width-modulation system, why is the transmitter's peak power much greater than its average power? 0 The signal duty cycle is less than 100% 1 The signal reaches peak amplitude only when voice modulated 0 The signal reaches peak amplitude only when voltage spikes are generated within the modulator 0 The signal reaches peak amplitude only when the pulses are also amplitude modulated 0 E8B15 What is one way that voice is transmitted in a pulse-width modulation system? 0 A standard pulse is varied in amplitude by an amount depending on the voice waveform at that instant 0 The position of a standard pulse is varied by an amount depending on the voice waveform at that instant 0 A standard pulse is varied in duration by an amount depending on the voice waveform at that instant 1 The number of standard pulses per second varies depending on the voice waveform at that instant 0 E8B17 Which of the following describe the three most-used symbols of an ITU emission designator? 0 Type of modulation, transmitted bandwidth and modulation code designator 0 Bandwidth of the modulating signal, nature of the modulating signal and transmission rate of signals 0 Type of modulation, nature of the modulating signal and type of information to be transmitted 1 Power of signal being transmitted, nature of multiplexing and transmission speed 0 E8B18 If the first symbol of an ITU emission designator is G, representing a phase-modulated signal, what information about the emission is described? 0 The nature of any signal multiplexing 0 The maximum permissible deviation 0 The nature of signals modulating the main carrier 0 The type of modulation of the main carrier 1 E8B19 In a pulse-position modulation system, what parameter does the modulating signal vary? 0 The number of pulses per second 0 Both the frequency and amplitude of the pulses 0 The duration of the pulses 0 The time at which each pulse occurs 1 E8B20 In a pulse-width modulation system, what parameter does the modulating signal vary? 0 Pulse frequency 0 Pulse duration 1 Pulse amplitude 0 Pulse intensity 0 E8B21 How are the pulses of a pulse-modulated signal usually transmitted? 0 A pulse of relatively short duration is sent; a relatively long period of time separates each pulse 1 A pulse of relatively long duration is sent; a relatively short period of time separates each pulse 0 A group of short pulses are sent in a relatively short period of time; a relatively long period of time separates each group 0 A group of short pulses are sent in a relatively long period of time; a relatively short period of time separates each group 0 E8B22 In an FM-phone signal, what is the term for the ratio between the deviation of the frequency modulated signal and the modulating frequency? 0 FM compressibility 0 Quieting index 0 Percentage of modulation 0 Modulation index 1 E8B23 What is meant by deviation ratio? 0 The ratio of the audio modulating frequency to the center carrier frequency 0 The ratio of the maximum carrier frequency deviation to the highest audio modulating frequency 1 The ratio of the carrier center frequency to the audio modulating frequency 0 The ratio of the highest audio modulating frequency to the average audio modulating frequency 0 E8B24 What is the deviation ratio of an FM-phone signal having a maximum frequency swing of plus or minus 7.5 kHz and accepting a maximum modulation rate of 3.5 kHz? 0 2.14 1 0.214 0 0.47 0 47 0 E8C01 What digital code consists of elements having unequal length? 0 ASCII 0 AX.25 0 Baudot 0 Morse code 1 E8C02 What are some of the differences between the Baudot digital code and ASCII? 0 Baudot uses four data bits per character, ASCII uses seven; Baudot uses one character as a shift code, ASCII has no shift code 0 Baudot uses five data bits per character, ASCII uses seven; Baudot uses two characters as shift codes, ASCII has no shift code 1 Baudot uses six data bits per character, ASCII uses seven; Baudot has no shift code, ASCII uses two characters as shift codes 0 Baudot uses seven data bits per character, ASCII uses eight; Baudot has no shift code, ASCII uses two characters as shift codes 0 E8C03 What is one advantage of using the ASCII code for data communications? 0 It includes built-in error-correction features 0 It contains fewer information bits per character than any other code 0 It is possible to transmit both upper and lower case text 1 It uses one character as a shift code to send numeric and special characters 0 E8C04 What digital communications system is well suited for meteor-scatter Communications at times other than during meteor showers? 0 ACSSB 0 Computerized high speed CW (HSCW) 1 AMTOR 0 Spread spectrum 0 E8C05 What type of error control system does Mode A AMTOR use? 0 Each character is sent twice 0 The receiving station checks the calculated frame check sequence (FCS) against the transmitted FCS 0 The receiving station checks the calculated frame parity against the transmitted parity 0 The receiving station automatically requests repeats when needed 1 E8C06 What type of error control system does Mode B AMTOR use? 0 Each character is sent twice 1 The receiving station checks the calculated frame check sequence (FCS) against the transmitted FCS 0 The receiving station checks the calculated frame parity against the computer-sequencing clock 0 The receiving station automatically requests repeats when needed 0 E8C07 What is the necessary bandwidth of a 13-WPM international Morse code emission A1A transmission? 0 Approximately 13 Hz 0 Approximately 26 Hz 0 Approximately 52 Hz 1 Approximately 104 Hz 0 E8C08 What is the necessary bandwidth for a 170-hertz shift, 300-baud ASCII emission J2D transmission? 0 0 Hz 0 0.3 kHz 0 0.5 kHz 1 1.0 kHz 0 E8C09 What is the necessary bandwidth of a 1000-Hz shift, 1200-baud ASCII emission F1D transmission? 0 1000 Hz 0 1200 Hz 0 440 Hz 0 2400 Hz 1 E8C10 What is the necessary bandwidth of a 4800-Hz frequency shift, 9600-baud ASCII emission F1D transmission? 0 15.36 kHz 1 9.6 kHz 0 4.8 kHz 0 5.76 kHz 0 E8C11 What term describes a wide-bandwidth communications system in which the RF carrier varies according to some predetermined sequence? 0 Amplitude compandored single sideband 0 AMTOR 0 Time-domain frequency modulation 0 Spread-spectrum communication 1 E8C12 What spread-spectrum communications technique alters the center frequency of a conventional carrier many times per second in accordance with a pseudo-random list of channels? 0 Frequency hopping 1 Direct sequence 0 Time-domain frequency modulation 0 Frequency compandored spread-spectrum 0 E8C13 What spread-spectrum communications technique uses a very fast binary bit stream to shift the phase of an RF carrier? 0 Frequency hopping 0 Direct sequence 1 Binary phase-shift keying 0 Phase compandored spread-spectrum 0 E8C14 What controls the spreading sequence of an amateur spread-spectrum transmission? 0 A frequency-agile linear amplifier 0 A crystal-controlled filter linked to a high-speed crystal switching mechanism 0 A binary linear-feedback shift register 1 A binary code which varies if propagation changes 0 E8C15 What makes spread-spectrum communications resistant to interference? 0 Interfering signals are removed by a frequency-agile crystal filter 0 Spread-spectrum transmitters use much higher power than conventional carrier-frequency transmitters 0 Spread-spectrum transmitters can hunt for the best carrier frequency to use within a given RF spectrum 0 Only signals using the correct spreading sequence are received 1 E8C16 What reduces interference from spread-spectrum transmitters to conventional communications in the same band? 0 A spread-spectrum transmitter avoids channels within the band which are in use by conventional transmitters 0 Spread-spectrum signals appear only as low-level noise in conventional receivers 1 Spread-spectrum signals change too rapidly to be detected by conventional receivers 0 Special crystal filters are needed in conventional receivers to detect spread-spectrum signals 0 E8D01 What is the term for the amplitude of the maximum positive excursion of a signal as viewed on an oscilloscope? 0 Peak-to-peak voltage 0 Inverse peak negative voltage 0 RMS voltage 0 Peak positive voltage 1 E8D02 What is the easiest voltage amplitude dimension to measure by viewing a pure sine wave signal on an oscilloscope? 0 Peak-to-peak voltage 1 RMS voltage 0 Average voltage 0 DC voltage 0 E8D03 What is the relationship between the peak-to-peak voltage and the peak voltage amplitude in a symmetrical waveform? 0 1:1 0 2:1 1 3:1 0 4:1 0 E8D04 What input-amplitude parameter is valuable in evaluating the signal-handling capability of a Class A amplifier? 0 Peak voltage 1 RMS voltage 0 An average reading power output meter 0 Resting voltage 0 E8D05 What is the PEP output of a transmitter that has a maximum peak of 30 volts to a 50-ohm load as observed on an oscilloscope? 0 4.5 watts 0 9 watts 1 16 watts 0 18 watts 0 E8D06 If an RMS reading AC voltmeter reads 65 volts on a sinusoidal waveform, what is the peak-to-peak voltage? 0 46 volts 0 92 volts 0 130 volts 0 184 volts 1 E8D07 What is the advantage of using a peak-reading voltmeter to monitor the output of a single-sideband transmitter? 0 It would be easy to calculate the PEP output of the transmitter 1 It would be easy to calculate the RMS output power of the transmitter 0 It would be easy to calculate the SWR on the transmission line 0 It would be easy to observe the output amplitude variations 0 E8D08 What is an electromagnetic wave? 0 Alternating currents in the core of an electromagnet 0 A wave consisting of two electric fields at right angles to each other 0 A wave consisting of an electric field and a magnetic field at right angles to each other 1 A wave consisting of two magnetic fields at right angles to each other 0 E8D09 Which of the following best describes electromagnetic waves traveling in free space? 0 Electric and magnetic fields become aligned as they travel 0 The energy propagates through a medium with a high refractive index 0 The waves are reflected by the ionosphere and return to their source 0 Changing electric and magnetic fields propagate the energy across a vacuum 1 E8D10 What is meant by circularly polarized electromagnetic waves? 0 Waves with an electric field bent into a circular shape 0 Waves with a rotating electric field 1 Waves that circle the Earth 0 Waves produced by a loop antenna 0 E8D11 What is the polarization of an electromagnetic wave if its magnetic field is parallel to the surface of the Earth? 0 Circular 0 Horizontal 0 Elliptical 0 Vertical 1 E8D12 What is the polarization of an electromagnetic wave if its magnetic field is perpendicular to the surface of the Earth? 0 Horizontal 1 Circular 0 Elliptical 0 Vertical 0 E8D13 What is the primary source of noise that can be heard in an HF-band receiver with an antenna connected? 0 Detector noise 0 Induction motor noise 0 Receiver front-end noise 0 Atmospheric noise 1 E8D14 At approximately what speed do electromagnetic waves travel in free space? 0 300 million meters per second 1 468 million meters per second 0 186,300 feet per second 0 300 million miles per second 0 E8D15 To ensure you do not exceed the maximum allowable power, what kind of meter would you use to monitor the output signal of a properly adjusted single-sideband transmitter? 0 An SWR meter reading in the forward direction 0 A modulation meter 0 An average reading wattmeter 0 A peak-reading wattmeter 1 E8D16 What is the average power dissipated by a 50-ohm resistive load during one complete RF cycle having a peak voltage of 35 volts? 0 12.2 watts 1 9.9 watts 0 24.5 watts 0 16 watts 0 E8D17 If an RMS reading voltmeter reads 34 volts on a sinusoidal waveform, what is the peak voltage? 0 123 volts 0 96 volts 0 55 volts 0 48 volts 1