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General License Class. Chapter 5 Radio Signals & Equipment (Part 1). Signal Review. Continuous Wave (CW) A signal at one frequency whose amplitude never varies. Normally used to refer to turning the signal on & off in a specific pattern to convey information. Morse Code. Signal Review.

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General license class

General License Class

Chapter 5

Radio Signals & Equipment

(Part 1)


Signal review

Signal Review

  • Continuous Wave (CW)

    • A signal at one frequency whose amplitude never varies.

    • Normally used to refer to turning the signal on & off in a specific pattern to convey information.

      • Morse Code.


Signal review1

Signal Review

  • Modulation

    • Changing a signal in some manner to convey information.

      • Can change amplitude (AM).

      • Can change frequency (FM).

      • Can change phase (PM).

      • A signal with no information is “unmodulated”.


Signal review2

Signal Review

  • Modulation

    • Changing a signal in some manner to convey information.

      • Voice mode or phone.

        • Information is voice.

          • Analog.

          • Digital.

      • Data mode or digital mode.

        • Information is data.


Signal review3

Signal Review

  • Amplitude Modulated Modes

    • Amplitude Modulation (AM).

      • Carrier plus two sidebands are transmitted.

      • Higher fidelity.

    • Single-Sideband (SSB).

      • Carrier & one sideband are suppressed.

        • Lower Sideband (LSB).

          • Only lower sideband is transmitted.

        • Upper sideband (USB).

          • Only upper sideband is transmitted.

      • Higher efficiency.

      • Less bandwidth.


Signal review4

Signal Review

  • Angle Modulated Modes

    • Frequency Modulation (FM).

      • Deviation = amount of frequency change.

    • Phase Modulation (PM).

    • Constant power whether modulated or not.


Signal review5

Signal Review

  • Bandwidth Definition

    • All modulated signals have sidebands.

    • FCC defines bandwidth as:

  • §97.3(a)(8) -- Bandwidth. The width of a frequency band outside of which the mean power of the transmitted signal is attenuated at least 26 dB below the mean power of the transmitted signal within the band.


Signal review6

Signal Review

  • Bandwidth Definition


G8a01 what is the name of the process that changes the envelope of an rf wave to carry information

G8A01 -- What is the name of the process that changes the envelope of an RF wave to carry information?

A.Phase modulation

B.Frequency modulation

C.Spread spectrum modulation

D.Amplitude modulation


G8a01 what is the name of the process that changes the envelope of an rf wave to carry information1

G8A01 -- What is the name of the process that changes the envelope of an RF wave to carry information?

A.Phase modulation

B.Frequency modulation

C.Spread spectrum modulation

D.Amplitude modulation


General license class

G8A02 -- What is the name of the process that changes the phase angle of an RF wave to convey information?

A.Phase convolution

B.Phase modulation

C.Angle convolution

D.Radian inversion


General license class

G8A02 -- What is the name of the process that changes the phase angle of an RF wave to convey information?

A.Phase convolution

B.Phase modulation

C.Angle convolution

D.Radian inversion


General license class

G8A03 -- What is the name of the process which changes the frequency of an RF wave to convey information?

A.Frequency convolution

B.Frequency transformation

C.Frequency conversion

D.Frequency modulation


General license class

G8A03 -- What is the name of the process which changes the frequency of an RF wave to convey information?

A.Frequency convolution

B.Frequency transformation

C.Frequency conversion

D.Frequency modulation


G8a05 what type of modulation varies the instantaneous power level of the rf signal

G8A05 -- What type of modulation varies the instantaneous power level of the RF signal?

A.Frequency shift keying

B.Pulse position modulation

C.Frequency modulation

D.Amplitude modulation


G8a05 what type of modulation varies the instantaneous power level of the rf signal1

G8A05 -- What type of modulation varies the instantaneous power level of the RF signal?

A.Frequency shift keying

B.Pulse position modulation

C.Frequency modulation

D.Amplitude modulation


G8a07 which of the following phone emissions uses the narrowest frequency bandwidth

G8A07 -- Which of the following phone emissions uses the narrowest frequency bandwidth?

A.Single sideband

B.Double sideband

C.Phase modulation

D.Frequency modulation


G8a07 which of the following phone emissions uses the narrowest frequency bandwidth1

G8A07 -- Which of the following phone emissions uses the narrowest frequency bandwidth?

A.Single sideband

B.Double sideband

C.Phase modulation

D.Frequency modulation


General license class

G8A11 -- What happens to the RF carrier signal when a modulating audio signal is applied to an FM transmitter?

A.The carrier frequency changes proportionally to the instantaneous amplitude of the modulating signal

B.The carrier frequency changes proportionally to the amplitude and frequency of the modulating signal

C.The carrier amplitude changes proportionally to the instantaneous frequency of the modulating signal

D.The carrier phase changes proportionally to the instantaneous amplitude of the modulating signal


General license class

G8A11 -- What happens to the RF carrier signal when a modulating audio signal is applied to an FM transmitter?

A.The carrier frequency changes proportionally to the instantaneous amplitude of the modulating signal

B.The carrier frequency changes proportionally to the amplitude and frequency of the modulating signal

C.The carrier amplitude changes proportionally to the instantaneous frequency of the modulating signal

D.The carrier phase changes proportionally to the instantaneous amplitude of the modulating signal


Digital modes

Digital Modes

  • Overview

    • Data speeds. (Clear as mud?)

      • Data rate = Bits per second (bps).

      • Symbol rate = Symbols per second (baud).

      • Data rate = symbol rate only if 1 symbol = 1 bit.

    • Duty cycle considerations.

      • Most digital modes are 100% duty cycle.

      • Most modern transmitters must reduce output power to avoid exceeding maximum average power output.


Digital modes1

Digital Modes

  • Bandwidth

    • Required bandwidth increases as symbol rate increases.

      • BW = B x K

        • B = Symbol rate in bauds.

        • K = Factor relating to shape of keying envelope.


Digital modes2

Digital Modes

  • Frequency Shift Keying (FSK) Modes.

    • Radioteletype (RTTY).

      • Oldest digital mode.

        • Still very popular.

      • Normal shift = 170 Hz.

      • Baudot code.

        • Characters = combinations of 5 bits each.

        • Each element = 1 data bit.

        • Maximum of 32 (25) characters.

          • LTRS & FIGS (shift codes).

        • Start & stop bits frame each character.


Digital modes3

Digital Modes

  • Frequency Shift Keying (FSK) Modes.

    • Multiple Frequency Shift Keying

      • MFSK16.

        • 16 tones, 15.625 Hz apart.

        • Data rate = 63 bps (42 wpm).

        • Bandwidth = 316 Hz (approx).

        • Good weak signal performance even though does not use error correction. (ERROR: MFSK16 uses FEC.)

      • MT63.

        • Uses 64 tones to modulate signal.

        • Bandwidth = 1 kHz.

        • Includes extensive error correction.


Digital modes4

Digital Modes

  • Phase-Shift Keying (PSK) Modes.

    • PSK31.

      • G3PLX developed PSK31 for keyboard-to-keyboard communications.

        • 31 = data rate (31.25 baud).

      • Uses variable-length code (Varicode).

        • Number of bits per character varies.

          • Most common characters have shortest code.

          • Uses 00 as separator between characters.

      • Bandwidth = 37.5 Hz.

        • Narrowest of all HF digital modes, including CW.


Digital modes5

Digital Modes

  • Packet Modes.

    • Packet basics.

      • Data to be sent is divided into “chunks”, control/status information is added before & after each "chunk” forming a “packet”.

        • Header -- Control & routing information and sometimes error correction information.

        • Data -- Typically 128 or 256 characters.

        • Trailer -- Check sum & possibly additional control & status information.


Digital modes6

Digital Modes

  • Packet Modes.

    • Packet basics.

      • Error detection.

        • Cyclic Redundancy Check (CRC).

          • A number calculated from all of the other bytes in the packet which is appended to the end o the packet.

          • Receiving system can calculate the CRC of the incoming packet, & if they don’t match ask the packet to be sent again.

        • Forward Error Correction (FEC).

          • Additional information is added to each packet to help receiving system reconstruct the packet if CRC fails.


Digital modes7

Digital Modes

  • Packet Modes.

    • Packet radio.

      • American Standard Code for Information Interchange (ASCII).

        • Characters = combinations of 7 elements each.

          • An 8th bit called a parity bit may be added.

          • Or the 8th bit could be an additional data bit.

        • Each element = 1 data bits.

        • Maximum of 128 (27) characters

          • 256 (28) maximum characters if 8 data bits.

        • Start bit & 1, 1.5, or 2 stop bits frame each character.

      • AX.25 Protocol.


Digital modes8

Digital Modes

  • Packet Modes.

    • Packet radio.

      • HF packet.

        • Limited to 300 baud.

        • Not well suited for HF propagation conditions.

      • VHF/UHF packet.

        • AFSK using FM transmitters at 1200 or 9600 baud.

        • Basis of APRS.


Digital modes9

Digital Modes

  • PACTOR & WINMOR

    • Teletype-Over-Radio (TOR).

      • TOR modes developed to improve reliability over RTTY.

        • Data sent in short bursts with error detection & error correction information.

          • AMTOR.

          • G-MOR.

        • More reliable, but slow.


Digital modes10

Digital Modes

  • PACTOR & WINMOR

    • PACTOR.

      • PACTOR-I developed by DL6MAA & DK4FV.

        • Uses FSK modulation.

        • Overcomes shortcomings of AMTOR & HF packet.

        • Works well in weak-signal & high-noise conditions.


Digital modes11

Digital Modes

  • PACTOR & WINMOR

    • PACTOR.

      • PACTOR-II & PACTOR-III used today.

        • Uses PSK modulation.

        • Automatic repeat request (ARQ) used to eliminate errors.

        • Adjusts speed (“trains”) to match conditions.

          • 5 kbps data rates possible.

        • Most popular modes for transferring large amounts of data.

    • WINMOR.

      • Like PACTOR but can use either FSK or PSK modulation.


G2e01 which mode is normally used when sending an rtty signal via afsk with an ssb transmitter

G2E01 -- Which mode is normally used when sending an RTTY signal via AFSK with an SSB transmitter?

A.USB

B.DSB

C.CW

D.LSB


G2e01 which mode is normally used when sending an rtty signal via afsk with an ssb transmitter1

G2E01 -- Which mode is normally used when sending an RTTY signal via AFSK with an SSB transmitter?

A.USB

B.DSB

C.CW

D.LSB


G2e02 how many data bits are sent in a single psk31 character

G2E02 -- How many data bits are sent in a single PSK31 character?

A.The number varies

B.5

C.7

D.8


G2e02 how many data bits are sent in a single psk31 character1

G2E02 -- How many data bits are sent in a single PSK31 character?

A.The number varies

B.5

C.7

D.8


G2e03 what part of a data packet contains the routing and handling information

G2E03 -- What part of a data packet contains the routing and handling information?

A.Directory

B.Preamble

C.Header

D.Footer


G2e03 what part of a data packet contains the routing and handling information1

G2E03 -- What part of a data packet contains the routing and handling information?

A.Directory

B.Preamble

C.Header

D.Footer


G2e05 which of the following describes baudot code

G2E05 -- Which of the following describes Baudot code?

A.A 7-bit code with start, stop and parity bits

B.A code using error detection and correction

C.A 5-bit code with additional start and stop bits

D.A code using SELCAL and LISTEN


G2e05 which of the following describes baudot code1

G2E05 -- Which of the following describes Baudot code?

A.A 7-bit code with start, stop and parity bits

B.A code using error detection and correction

C.A 5-bit code with additional start and stop bits

D.A code using SELCAL and LISTEN


G2e06 what is the most common frequency shift for rtty emissions in the amateur hf bands

G2E06 -- What is the most common frequency shift for RTTY emissions in the amateur HF bands?

A.85 Hz

B.170 Hz

C.425 Hz

D.850 Hz


G2e06 what is the most common frequency shift for rtty emissions in the amateur hf bands1

G2E06 -- What is the most common frequency shift for RTTY emissions in the amateur HF bands?

A.85 Hz

B.170 Hz

C.425 Hz

D.850 Hz


G2e10 what is a major advantage of mfsk16 compared to other digital modes

G2E10 -- What is a major advantage of MFSK16 compared to other digital modes?

A.It is much higher speed than RTTY

B.It is much narrower bandwidth than most digital modes

C.It has built-in error correction

D.It offers good performance in weak signal environments without error correction


G2e10 what is a major advantage of mfsk16 compared to other digital modes1

G2E10 -- What is a major advantage of MFSK16 compared to other digital modes?

A.It is much higher speed than RTTY

B.It is much narrower bandwidth than most digital modes

C.It has built-in error correction

D.It offers good performance in weak signal environments without error correction


G2e12 how does the receiving station respond to an arq data mode packet containing errors

G2E12 -- How does the receiving station respond to an ARQ data mode packet containing errors?

A.Terminates the contact

B.Requests the packet be retransmitted

C.Sends the packet back to the transmitting station

D.Requests a change in transmitting protocol


G2e12 how does the receiving station respond to an arq data mode packet containing errors1

G2E12 -- How does the receiving station respond to an ARQ data mode packet containing errors?

A.Terminates the contact

B.Requests the packet be retransmitted

C.Sends the packet back to the transmitting station

D.Requests a change in transmitting protocol


G2e13 in the pactor protocol what is meant by an nak response to a transmitted packet

G2E13 -- In the PACTOR protocol, what is meant by an NAK response to a transmitted packet?

A.The receiver is requesting the packet be re-transmitted

B.The receiver is reporting the packet was received without error

C.The receiver is busy decoding the packet

D.The entire file has been received correctly


G2e13 in the pactor protocol what is meant by an nak response to a transmitted packet1

G2E13 -- In the PACTOR protocol, what is meant by an NAK response to a transmitted packet?

A.The receiver is requesting the packet be re-transmitted

B.The receiver is reporting the packet was received without error

C.The receiver is busy decoding the packet

D.The entire file has been received correctly


G8b08 why is it important to know the duty cycle of the data mode you are using when transmitting

G8B08 -- Why is it important to know the duty cycle of the data mode you are using when transmitting?

A.To aid in tuning your transmitter

B.Some modes have high duty cycles which could exceed the transmitter's average power rating.

C.To allow time for the other station to break in during a transmission

D.All of these choices are correct


G8b08 why is it important to know the duty cycle of the data mode you are using when transmitting1

G8B08 -- Why is it important to know the duty cycle of the data mode you are using when transmitting?

A.To aid in tuning your transmitter

B.Some modes have high duty cycles which could exceed the transmitter's average power rating.

C.To allow time for the other station to break in during a transmission

D.All of these choices are correct


General license class

G8B11 -- How does forward error correction allow the receiver to correct errors in received data packets?

A.By controlling transmitter output power for optimum signal strength

B.By using the varicode character set

C.By transmitting redundant information with the data

D.By using a parity bit with each character


General license class

G8B11 -- How does forward error correction allow the receiver to correct errors in received data packets?

A.By controlling transmitter output power for optimum signal strength

B.By using the varicode character set

C.By transmitting redundant information with the data

D.By using a parity bit with each character


G8b12 what is the relationship between transmitted symbol rate and bandwidth

G8B12 -- What is the relationship between transmitted symbol rate and bandwidth?

A.Symbol rate and bandwidth are not related

B.Higher symbol rates require higher bandwidth

C.Lower symbol rates require higher bandwidth

D.Bandwidth is constant for data mode signals


G8b12 what is the relationship between transmitted symbol rate and bandwidth1

G8B12 -- What is the relationship between transmitted symbol rate and bandwidth?

A.Symbol rate and bandwidth are not related

B.Higher symbol rates require higher bandwidth

C.Lower symbol rates require higher bandwidth

D.Bandwidth is constant for data mode signals


Break

Break


Radio s building blocks

Radio’s Building Blocks

  • Oscillators

    • Generates sine wave.

    • Amplifier with positive feedback.

      • AV = Amplifier gain.

      • β = Feedback ratio.

      • Loop Gain = AV x β

      • If loop gain > 1 and in phase, circuit will oscillate.


Radio s building blocks1

Radio’s Building Blocks

  • Oscillators

    • Colpitts oscillator.

    • Hartley oscillator.

Frequency determined by values of L & C.

Frequency determined by values of L & C.


Radio s building blocks2

Radio’s Building Blocks

  • Oscillators

    • Pierce oscillator.

    • Crystals.

      • Usually small wafer of quartz with precise dimensions.

      • Piezoelectric effect.

        • Crystal deforms mechanically when voltage applied.

        • Voltage generated when crystal deformed.

Frequency determined by crystal.


Radio s building blocks3

Radio’s Building Blocks

  • Oscillators

    • Variable-frequency oscillator (VFO).

      • Make either L or C adjustable (usually C).

      • Not as stable.

      • Used to tune radio to different frequencies.


Radio s building blocks4

Radio’s Building Blocks

  • Oscillators

    • Variable-frequency oscillator (VFO).

      • “Crystal-controlled” VFO’s.

        • Phase-Lock-Loop (PLL).

        • Direct Digital Synthesis (DDS)

      • Stability of crystal oscillator.

      • Can be controlled by software.


Radio s building blocks5

Radio’s Building Blocks

  • Mixers

    • Mixing is also known as heterodyning.

    • Used to change the frequency of a signal.

    • Mathematically multiplies 2 frequencies together, generating 4 output frequencies.

      • f1 x f2 f1, f2, f1+f2, f1–f2

    • Operation of a mixer is similar to operation of detectors & modulators.


Radio s building blocks6

Radio’s Building Blocks

  • Mixers


Radio s building blocks7

Radio’s Building Blocks

  • Mixers

    • Single-balanced mixer.

      • Local oscillator or input signal is suppressed, but not both.


Signal processing

Signal Processing

  • Mixers

    • Double-balanced mixer.

      • fRF & fLO are suppressed leaving only sum & difference frequencies.


Radio s building blocks8

Radio’s Building Blocks

  • Multipliers

    • A multiplier stage creates a multiple of the input frequency.

    • An amplifier stage designed to have a lot of distortion (harmonics) & output circuit is tuned to the desired harmonic.

      • Class C amplifier.

    • Used in VHF/UHF transmitters to generate FM/PM modulated signal at a low frequency & then multiplied to the desired frequency.


Radio s building blocks9

Radio’s Building Blocks

  • Modulators

    • Amplitude Modulators.

      • Plate modulation.

        • Originally, AM was produced by varying the DC plate voltage to the final stage of a CW transmitter.

          • If solid-state transmitter, substitute collector or drain for plate.

        • Requires a LOT of audio power.

          • 1 kW transmitter needs 1 kW of audio!

      • Screen modulation.

        • Applied AF to screen voltage of final stage.

          • Less AF power required, but worse quality.


Radio s building blocks10

Radio’s Building Blocks

  • Modulators

    • Amplitude Modulators.

      • AM can be generated by mixing the modulating signal (fM) with a carrier (fC).

        • fC x fM fC, fM, fC+fM, fC–fM

      • Using a single-balanced mixer, an AM signal is generated & you don’t have to filter out the modulating signal.

        • fC x fM fC, fC+fM, fC–fM

      • Using a double-balanced mixer, a double-sideband (DSB) signal is produced.

        • fC x fM fC+fM, fC–fM


Radio s building blocks11

Radio’s Building Blocks

  • Modulators

    • Amplitude Modulators.

      • AM can be generated by mixing the modulating signal (fM) with a carrier (fC).

        • fC x fM fC, fM, fC+fM, fC–fM


Radio s building blocks12

Radio’s Building Blocks

  • Modulators

    • Amplitude Modulators.

      • Using a double-balanced mixer, a double-sideband (DSB) signal is produced.

        • fC x fM fC+fM, fC–fM


Radio s building blocks13

Radio’s Building Blocks

  • Modulators

    • Amplitude Modulators.

      • The double-sideband signal is then converted to a SSB signal by filtering out the unwanted sideband.

        • Filter method of SSB generation.

OR


Radio s building blocks14

Radio’s Building Blocks

  • Modulators

    • Amplitude Modulators.

      • Phase method of SSB generation.

        • 2 double-balanced mixers.

        • 2 carrier signals 90° out-of-phase

        • 2 modulating signals 90° out-of-phase

          • REALLY difficult to create in hardware.

          • Easy to create in software.


Radio s building blocks15

Radio’s Building Blocks

  • Modulators

    • Amplitude Modulators.

      • Advantages of SSB.

        • Transmitter power used more effectively.

          • In AM signal, 1/2 of power is in carrier.

          • In AM signal, 1/2 of remaining power is in each sideband.

          • Sidebands carry same information.

          • In AM, only 25% of available power is used to transmit the information.

          • In SSB, 100% of transmitter power is used.

        • 1/2 the bandwidth of AM.


Radio s building blocks16

Radio’s Building Blocks

  • Modulators

    • Frequency & Phase Modulators.

      • Frequency modulation (FM).

        • Carrier frequency deviates in proportion to amplitude of the modulating signal.

      • Phase modulation (PM).

        • Carrier frequency deviates in proportion to both the amplitude and the frequency of the modulating signal.

      • By changing the audio frequency response of the modulator, an FM modulator can be used to generate PM and vice versa.


Radio s building blocks17

Radio’s Building Blocks

  • Modulators

    • Frequency & Phase Modulators.

      • Both FM & PM sound the same on the air (almost).

        • Only difference is in frequency response of the audio.

      • Both FM & PM can be demodulated with the same circuitry.

      • Design of modulator circuit determines whether FM or PM.

        • FM = modulation applied to oscillator circuit.

        • PM = modulation applied to amplifier stage following the oscillator.


General license class

G4D08 -- What frequency range is occupied by a 3 kHz LSB signal when the displayed carrier frequency is set to 7.178 MHz?

A.7.178 to 7.181 MHz

B.7.178 to 7.184 MHz

C.7.175 to 7.178 MHz

D.7.1765 to 7.1795 MHz


General license class

G4D08 -- What frequency range is occupied by a 3 kHz LSB signal when the displayed carrier frequency is set to 7.178 MHz?

A.7.178 to 7.181 MHz

B.7.178 to 7.184 MHz

C.7.175 to 7.178 MHz

D.7.1765 to 7.1795 MHz


General license class

G4D09 -- What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?

A.14.347 to 14.647 MHz

B.14.347 to 14.350 MHz

C.14.344 to 14.347 MHz

D.14.3455 to 14.3485 MHz


General license class

G4D09 -- What frequency range is occupied by a 3 kHz USB signal with the displayed carrier frequency set to 14.347 MHz?

A.14.347 to 14.647 MHz

B.14.347 to 14.350 MHz

C.14.344 to 14.347 MHz

D.14.3455 to 14.3485 MHz


General license class

G4D10 -- How close to the lower edge of the 40 meter General Class phone segment should your displayed carrier frequency be when using 3 kHz wide LSB?

A.3 kHz above the edge of the segment

B.3 kHz below the edge of the segment

C.Your displayed carrier frequency may be set at the edge of the segment

D.Center your signal on the edge of the segment


General license class

G4D10 -- How close to the lower edge of the 40 meter General Class phone segment should your displayed carrier frequency be when using 3 kHz wide LSB?

A.3 kHz above the edge of the segment

B.3 kHz below the edge of the segment

C.Your displayed carrier frequency may be set at the edge of the segment

D.Center your signal on the edge of the segment


General license class

G4D11 -- How close to the upper edge of the 20 meter General Class band should your displayed carrier frequency be when using 3 kHz wide USB?

A.3 kHz above the edge of the band

B.3 kHz below the edge of the band

C.Your displayed carrier frequency may be set at the edge of the band

D.Center your signal on the edge of the band


General license class

G4D11 -- How close to the upper edge of the 20 meter General Class band should your displayed carrier frequency be when using 3 kHz wide USB?

A.3 kHz above the edge of the band

B.3 kHz below the edge of the band

C.Your displayed carrier frequency may be set at the edge of the band

D.Center your signal on the edge of the band


G7b07 what are the basic components of virtually all sine wave oscillators

G7B07 -- What are the basic components of virtually all sine wave oscillators?

A.An amplifier and a divider

B.A frequency multiplier and a mixer

C.A circulator and a filter operating in a feed-forward loop

D.A filter and an amplifier operating in a feedback loop


G7b07 what are the basic components of virtually all sine wave oscillators1

G7B07 -- What are the basic components of virtually all sine wave oscillators?

A.An amplifier and a divider

B.A frequency multiplier and a mixer

C.A circulator and a filter operating in a feed-forward loop

D.A filter and an amplifier operating in a feedback loop


G7b09 what determines the frequency of an lc oscillator

G7B09 -- What determines the frequency of an LC oscillator?

A.The number of stages in the counter

B.The number of stages in the divider

C.The inductance and capacitance in the tank circuit

D.The time delay of the lag circuit


G7b09 what determines the frequency of an lc oscillator1

G7B09 -- What determines the frequency of an LC oscillator?

A.The number of stages in the counter

B.The number of stages in the divider

C.The inductance and capacitance in the tank circuit

D.The time delay of the lag circuit


General license class

G7C05 -- Which of the following is an advantage of a transceiver controlled by a direct digital synthesizer (DDS)?

A. Wide tuning range and no need for band switching

B. Relatively high power output

C. Relatively low power consumption

D. Variable frequency with the stability of a crystal oscillator


General license class

G7C05 -- Which of the following is an advantage of a transceiver controlled by a direct digital synthesizer (DDS)?

A. Wide tuning range and no need for band switching

B. Relatively high power output

C. Relatively low power consumption

D. Variable frequency with the stability of a crystal oscillator


G8a04 what emission is produced by a reactance modulator connected to an rf power amplifier

G8A04 -- What emission is produced by a reactance modulator connected to an RF power amplifier?

A.Multiplex modulation

B.Phase modulation

C.Amplitude modulation

D.Pulse modulation


G8a04 what emission is produced by a reactance modulator connected to an rf power amplifier1

G8A04 -- What emission is produced by a reactance modulator connected to an RF power amplifier?

A.Multiplex modulation

B.Phase modulation

C.Amplitude modulation

D.Pulse modulation


G8a06 what is one advantage of carrier suppression in a single sideband phone transmission

G8A06 -- What is one advantage of carrier suppression in a single-sideband phone transmission?

A.Audio fidelity is improved

B.Greater modulation percentage is obtainable with lower distortion

C.The available transmitter power can be used more effectively

D.Simpler receiving equipment can be used


G8a06 what is one advantage of carrier suppression in a single sideband phone transmission1

G8A06 -- What is one advantage of carrier suppression in a single-sideband phone transmission?

A.Audio fidelity is improved

B.Greater modulation percentage is obtainable with lower distortion

C.The available transmitter power can be used more effectively

D.Simpler receiving equipment can be used


G8a12 what signal s would be found at the output of a properly adjusted balanced modulator

G8A12 -- What signal(s) would be found at the output of a properly adjusted balanced modulator?

A.Both upper and lower sidebands

B.Either upper or lower sideband, but not both

C.Both upper and lower sidebands and the carrier

D.The modulating signal and the unmodulated carrier


G8a12 what signal s would be found at the output of a properly adjusted balanced modulator1

G8A12 -- What signal(s) would be found at the output of a properly adjusted balanced modulator?

A.Both upper and lower sidebands

B.Either upper or lower sideband, but not both

C.Both upper and lower sidebands and the carrier

D.The modulating signal and the unmodulated carrier


General license class

G8B01 -- What receiver stage combines a 14.250 MHz input signal with a 13.795 MHz oscillator signal to produce a 455 kHz intermediate frequency (IF) signal?

A.Mixer

B.BFO

C.VFO

D.Discriminator


General license class

G8B01 -- What receiver stage combines a 14.250 MHz input signal with a 13.795 MHz oscillator signal to produce a 455 kHz intermediate frequency (IF) signal?

A.Mixer

B.BFO

C.VFO

D.Discriminator


G8b03 what is another term for the mixing of two rf signals

G8B03 -- What is another term for the mixing of two RF signals?

A.Heterodyning

B.Synthesizing

C.Cancellation

D.Phase inverting


G8b03 what is another term for the mixing of two rf signals1

G8B03 -- What is another term for the mixing of two RF signals?

A.Heterodyning

B.Synthesizing

C.Cancellation

D.Phase inverting


General license class

G8B04 -- What is the name of the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?

A.Mixer

B.Reactance modulator

C.Pre-emphasis network

D.Multiplier


General license class

G8B04 -- What is the name of the stage in a VHF FM transmitter that generates a harmonic of a lower frequency signal to reach the desired operating frequency?

A.Mixer

B.Reactance modulator

C.Pre-emphasis network

D.Multiplier


Questions

Questions?


Next week

Next Week

Chapter 5

Radio Signals & Equipment

(Part 2)


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