Canadian Basic Qualification pool, section B-003-006

Subelement B-003

B-003

Section B-003-006

B-003-006-001

In a single-sideband transmitter, what does the fixed RF oscillator do?

Correct Answer
A.
It produces an RF carrier
B.
It drives the mixer
C.
It directly drives the sideband filter
D.
It balances the variable frequency oscillator

B-003-006-001

The SSB Transmitter block diagram: The balanced modulator takes in two signals: a fixed frequency from an RF Oscillator and the microphone signal after it has passed through a speech amplifier. The balanced modulator produces a double-sideband suppressed-carrier signal. After the balanced modulator, a filter selects the desired sideband. This SSB signal is mixed with a variable frequency oscillator (VFO) signal by a mixer. Out of the mixer, the SSB signal is now at the operating frequency and is taken through a power amplifier. In the case of the SSB transmitter, this final power amplifier must be linear (distortion free).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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B-003-006-002

In a single-sideband transmitter, why is the speech amplifier needed?

Correct Answer
A.
Microphones usually have a low power output
B.
To match the balanced modulator's output impedance
C.
The sideband filter requires a large audio signal to work
D.
To improve signal fidelity

B-003-006-002

In all our voice transmitters, the signal received from the microphone has a small amplitude, it must be amplified to be made useful.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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B-003-006-003

In a typical single-sideband transmitter, what is the purpose of the filter that follows the balanced modulator?

Correct Answer
A.
Remove the unwanted sideband
B.
Suppress the RF carrier signal
C.
Remove harmonics from the transmitted signal
D.
Shape the audio waveform

B-003-006-003

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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B-003-006-004

In a typical single-sideband transmitter, at what frequency is the sideband filter tuned?

A.
At the VFO frequency
Correct Answer
B.
Near the fixed RF oscillator frequency
C.
Near the operating frequency
D.
At audio frequencies

B-003-006-004

The two sidebands produced by the balanced modulator sit on either side of the fixed oscillator frequency. The filter retains one of them.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-003-006-005

In a single-sideband transmitter, what is the purpose of the speech amplifier?

Correct Answer
A.
Amplify the audio you wish to transmit
B.
Amplify one of the signal's two sidebands
C.
Amplify the signal's harmonic content
D.
Amplify the signal's carrier

B-003-006-005

In all our voice transmitters, the signal received from the microphone has a small amplitude, it must be amplified to be made useful.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-003-006-006

In a single-sideband transmitter, which stage transposes the single-sideband signal to the operating frequency?

A.
Fixed RF oscillator
B.
Variable frequency oscillator
C.
Balanced modulator
Correct Answer
D.
Mixer

B-003-006-006

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-003-006-007

In a single-sideband transmitter, which stage allows you to adjust the final transmit frequency?

A.
Sideband filter
B.
Balanced modulator
Correct Answer
C.
Variable frequency oscillator
D.
Antenna tuner

B-003-006-007

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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B-003-006-008

In a single-sideband transmitter, which stage normally includes a circuit providing protection from excessive SWR?

A.
Speech amplifier
Correct Answer
B.
Final amplifier
C.
Variable frequency oscillator
D.
Balanced modulator

B-003-006-008

A circuit, included at the output of the final amplifier, recognizes a serious impedance mismatch in the antenna system and protects the amplifier by reducing output power. This protection is generally present in all our transmitters.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

B-003-006-009

In a single-sideband transmitter, which stage transposes the voice message from the audio spectrum to the radio spectrum?

A.
Variable frequency oscillator
Correct Answer
B.
Balanced modulator
C.
Mixer
D.
Fixed RF oscillator

B-003-006-009

The SSB transmitter performs two translations: the first transposes the voice up to a working frequency right next to the fixed oscillator frequency, and a second from that working frequency to the operating frequency.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

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