B-003-11: Transmitter, carrier, keying, and amplitude modulation fundamentals
B-003-11-01:
What does chirp mean?
A small change in a transmitter's frequency each time it is keyed
A high-pitched tone which is received along with a CW signal
A slow change in transmitter frequency as the circuit warms up
An overload in a receiver's audio circuit whenever CW is received
B-003-11-02:
What can be done to keep a CW transmitter from chirping?
Keep the power supply voltages very steady
Add a key-click filter
Keep the power supply current very steady
Add a low pass filter
B-003-11-03:
What circuit has a variable-frequency oscillator connected to a driver and a power amplifier?
A VFO-controlled transmitter
A crystal-controlled transmitter
A single-sideband transmitter
A packet-radio transmitter
B-003-11-04:
What type of modulation system changes the amplitude of an RF wave for the purpose of conveying information?
Amplitude modulation
Phase modulation
Amplitude-rectification modulation
Frequency modulation
B-003-11-05:
In what emission type does the instantaneous amplitude (envelope) of the RF signal vary in accordance with the modulating audio?
Amplitude modulation
Frequency modulation
Pulse modulation
Frequency shift keying
B-003-11-06:
Morse code is usually transmitted by radio as:
an interrupted carrier
a series of key-clicks
a continuous carrier
a voice-modulated carrier
B-003-11-07:
A mismatched antenna or feedline may present an incorrect load to the transmitter. The result may be:
excessive heat produced in the final transmitter stage
loss of modulation in the transmitted signal
the driver stage will not deliver power to the final
the output tank circuit breaks down
B-003-11-08:
One result of a slight mismatch between the power amplifier of a transmitter and the antenna would be:
reduced antenna radiation
smaller DC current drain
lower modulation percentage
radiated key-clicks
B-003-11-09:
An RF oscillator should be electrically and mechanically stable. This is to ensure that the oscillator does not:
drift in frequency
become over modulated
generate key-clicks
cause undue distortion
B-003-11-10:
The input power to the final stage of your transmitter is 200 watts and the output is 125 watts. What has happened to the remaining power?
It has been dissipated as heat loss
It has been used to provide greater efficiency
It has been used to provide negative feedback
It has been used to provide positive feedback
B-003-11-11:
The difference between DC input power and RF output power of a transmitter RF amplifier:
appears as heat dissipation
is lost in the feed line
is due to oscillating
radiates from the antenna
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