% FILENAME = N18.TXT
% Transmitter Block Diagrams
% Release version 3, October 2001  

%Question 1
#18.1 In the transmitter block diagram shown, the "oscillator": 
<img src = "ssbtx.gif" align = center width = 483 height = 145> 
<totallines = 15 >

is variable in frequency 

generates an audio frequency tone during tests 

uses a crystal for good frequency stability 

may have a calibrated dial 

% ans 3


%Question 2 
#18.2 In the transmitter block diagram shown, the "balanced modulator": 
<img src = "ssbtx.gif" align = center width = 483 height = 145> 
<totallines = 15 >

balances the high and low frequencies in the audio signal 

performs double sideband suppressed carrier modulation 

acts as a tone control 

balances the standing wave ratio 

% ans 2 


%Question 3 
#18.3 In the transmitter block diagram shown, the "filter": 
<img src = "ssbtx.gif" align = center width = 483 height = 145> 
<totallines = 15 >

removes mains hum from the audio signal 

suppresses unwanted harmonics of the RF signal 

removes one sideband from the modulated signal 

removes the carrier component from the modulated signal 

% ans 3 


%Question 4
#18.4 In the transmitter block diagram shown, the "mixer": 
<img src = "ssbtx.gif" align = center width = 483 height = 145> 
<totallines = 15 >

adds the correct proportion of carrier to the SSB signal 

mixes the audio and RF signals in the correct proportions 

translates the SSB signal to the required frequency 

mixes the two sidebands in the correct proportions 

% ans 3 


%Question 5
#18.5 In the transmitter block diagram shown, the "linear amplifier": 
<img src = "ssbtx.gif" align = center width = 483 height = 145> 
<totallines = 15 >

has all components arranged in-line 

amplifies the modulated signal with no distortion 

aligns the two sidebands correctly 

removes any unwanted amplitude modulation from the signal 

% ans 2

%Question 6
#18.6 In the transmitter block diagram shown, the "VFO" is: 
<img src = "ssbtx.gif" align = center width = 483 height = 145> 
<totallines = 15 >

a voice frequency oscillator 

a varactor fixed oscillator 

a virtual faze oscillator 

a variable frequency oscillator 

% ans 4


%Question 7
#18.7 In the transmitter block diagram shown, the "master oscillator" produces:
<img src = "cwtx.gif" align = center width = 404 height = 163>
<totallines = 13>

a steady signal at the required carrier frequency 

a pulsating signal at the required carrier frequency 

a 800 Hz signal to modulate the carrier 

a modulated CW signal 

% ans 1


%Question 8
#18.8 In the transmitter block diagram shown, the "driver buffer": 
<img src = "cwtx.gif" align = center width = 404 height = 163> 
<totallines = 13>

filters any sharp edges from the input signal 

drives the power amplifier into saturation 

provides isolation between the oscillator and power amplifier 

changes the frequency of the master oscillator signal 

% ans 3


%Question 9
#18.9 In the transmitter block diagram shown, the "Morse key": 
<img src = "cwtx.gif" align = center width = 404 height = 163> 
<totallines = 13>

turns the DC power to the transmitter on and off 

allows the oscillator signal to pass only when the key is depressed 

changes the frequency of the transmitted signal when the key is 
depressed 

adds an 800 Hz audio tone to the signal when the key is depressed 

% ans 2



%Question 10
#18.10 In the transmitter block diagram shown, the "power amplifier": 
<img src = "cwtx.gif" align = center width = 404 height = 163> 
<totallines = 13 >

need not have linear characteristics 

amplifies the bandwidth of its input signal 

must be adjusted during key-up conditions 

should be water-cooled 

% ans 1


%Question 11
#18.11 In the transmitter block diagram shown, the "speech amplifier": 
<img src = "fmtx.gif" align = center width = 600 height = 143> 
<totallines = 16 >

amplifies the audio signal from the microphone 

is a spectral equalization entropy changer 

amplifies only speech, while discriminating against background noises 

shifts the frequency spectrum of the audio signal into the RF region 

% ans 1


%Question 12
#18.12 In the transmitter block diagram shown, the "modulator": 
<img src = "fmtx.gif" align = center width = 600 height = 143> 
<totallines = 16>

is an amplitude modulator with feedback 

is an SSB modulator with feedback 

causes the speech waveform to gate the oscillator on and off 

causes the speech waveform to shift the frequency of the oscillator 

% ans 4


%Question 13
#18.13 In the transmitter block diagram shown, the "oscillator" is: 
<img src = "fmtx.gif" align = center width = 600 height = 143> 
<totallines = 16 >

an audio frequency oscillator 

a variable frequency RF oscillator 

a beat frequency oscillator 

a variable frequency audio oscillator 

% ans 2


%Question 14
#18.14 In the transmitter block diagram shown, the "frequency multiplier": 
<img src = "fmtx.gif" align = center width = 600 height = 143> 
<totallines = 16 >

translates the frequency of the modulated signal into the RF spectrum 

changes the frequency of the speech signal 

produces a harmonic of the oscillator signal 

multiplies the oscillator signal by the speech signal 

% ans 3





%Question 15
#18.15 In the transmitter block diagram shown, the "power amplifier": 
<img src = "fmtx.gif" align = center width = 600 height = 143> 
<totallines = 16 >

increases the voltage of the mains to drive the antenna 

amplifies the audio frequency component of the signal 

amplifies the selected sideband to a suitable level 

amplifies the RF signal to a suitable level 

% ans 4

%Question 16
#18.16 The signal from an amplitude modulated transmitter consists of: 

a carrier and two sidebands 

a carrier and one sideband 

no carrier and two sidebands 

no carrier and one sideband 

% ans 1

%Question 17
#18.17 The signal from a frequency modulated transmitter has: 

an amplitude which varies with the modulating waveform 

a frequency which varies with the modulating waveform 

a single sideband which follows the modulating waveform 

no sideband structure 

% ans 2

%Question 18
#18.18 The signal from a balanced modulator consists of: 

a carrier and two sidebands 

a carrier and one sideband 

no carrier and two sidebands 

no carrier and one sideband 

% ans 3

%Question 19
#18.19 The signal from a CW transmitter consists of: 

a continuous, unmodulated RF waveform 

a continuous RF waveform modulated with an 800 Hz Morse signal 

an RF waveform which is keyed on and off to form Morse characters 

a continuous RF waveform which changes frequency in synchronism with 
an applied Morse signal 

% ans 3

%Question 20
#18.20 The following signal can be amplified using a non-linear 
amplifier: 

SSB 

FM 

AM 

DSBSC 

% ans 2

 




