E7H01:
What are three oscillator circuits used in amateur radio equipment?
- Taft, Pierce and negative feedback
- Pierce, Fenner and Beane
- Taft, Hartley and Pierce
- Colpitts, Hartley and Pierce
E7H02:
What is a microphonic?
- An IC used for amplifying microphone signals
- Distortion caused by RF pickup on the microphone cable
- Changes in oscillator frequency due to mechanical vibration
- Excess loading of the microphone by an oscillator
E7H03:
How is positive feedback supplied in a Hartley oscillator?
- Through a tapped coil
- Through a capacitive divider
- Through link coupling
- Through a neutralizing capacitor
E7H04:
How is positive feedback supplied in a Colpitts oscillator?
- Through a tapped coil
- Through link coupling
- Through a capacitive divider
- Through a neutralizing capacitor
E7H05:
How is positive feedback supplied in a Pierce oscillator?
- Through a tapped coil
- Through link coupling
- Through a neutralizing capacitor
- Through a quartz crystal
E7H06:
Which of the following oscillator circuits are commonly used in VFOs?
- Pierce and Zener
- Colpitts and Hartley
- Armstrong and deForest
- Negative feedback and balanced feedback
E7H07:
How can an oscillator's microphonic responses be reduced?
- Use NP0 capacitors
- Reduce noise on the oscillator's power supply
- Increase the bias voltage
- Mechanically isolate the oscillator circuitry from its enclosure
E7H08:
Which of the following components can be used to reduce thermal drift in crystal oscillators?
- NP0 capacitors
- Toroidal inductors
- Wirewound resistors
- Non-inductive resistors
E7H09:
What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital to analog converter, and a low-pass anti-alias filter?
- A direct digital synthesizer
- A hybrid synthesizer
- A phase-locked loop synthesizer
- A diode-switching matrix synthesizer
E7H10:
What information is contained in the lookup table of a direct digital synthesizer (DDS)?
- The phase relationship between a reference oscillator and the output waveform
- Amplitude values that represent the desired waveform
- The phase relationship between a voltage-controlled oscillator and the output waveform
- Frequently used receiver and transmitter frequencies
E7H11:
What are the major spectral impurity components of direct digital synthesizers?
- Broadband noise
- Digital conversion noise
- Spurious signals at discrete frequencies
- Nyquist limit noise
E7H12:
Which of the following must be done to ensure that a crystal oscillator provides the frequency specified by the crystal manufacturer?
- Provide the crystal with a specified parallel inductance
- Provide the crystal with a specified parallel capacitance
- Bias the crystal at a specified voltage
- Bias the crystal at a specified current
E7H13:
Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?
- Use a GPS signal reference
- Use a rubidium stabilized reference oscillator
- Use a temperature-controlled high Q dielectric resonator
- All these choices are correct
E7H14:
What is a phase-locked loop circuit?
- An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
- An electronic circuit also known as a monostable multivibrator
- An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
- An electronic circuit consisting of a precision push-pull amplifier with a differential input
E7H15:
Which of these functions can be performed by a phase-locked loop?
- Wide-band AF and RF power amplification
- Comparison of two digital input signals, digital pulse counter
- Photovoltaic conversion, optical coupling
- Frequency synthesis, FM demodulation