E7H01:

What are three oscillator circuits used in amateur radio equipment?

1. Taft, Pierce and negative feedback
2. Pierce, Fenner and Beane
3. Taft, Hartley and Pierce
4. Colpitts, Hartley and Pierce

E7H02:

What is a microphonic?

1. An IC used for amplifying microphone signals
2. Distortion caused by RF pickup on the microphone cable
3. Changes in oscillator frequency due to mechanical vibration
4. Excess loading of the microphone by an oscillator

E7H03:

How is positive feedback supplied in a Hartley oscillator?

1. Through a tapped coil
2. Through a capacitive divider
3. Through link coupling
4. Through a neutralizing capacitor

E7H04:

How is positive feedback supplied in a Colpitts oscillator?

1. Through a tapped coil
2. Through link coupling
3. Through a capacitive divider
4. Through a neutralizing capacitor

E7H05:

How is positive feedback supplied in a Pierce oscillator?

1. Through a tapped coil
2. Through link coupling
3. Through a neutralizing capacitor
4. Through a quartz crystal

E7H06:

Which of the following oscillator circuits are commonly used in VFOs?

1. Pierce and Zener
2. Colpitts and Hartley
3. Armstrong and deForest
4. Negative feedback and balanced feedback

E7H07:

How can an oscillator's microphonic responses be reduced?

1. Use NP0 capacitors
2. Reduce noise on the oscillator's power supply
3. Increase the bias voltage
4. Mechanically isolate the oscillator circuitry from its enclosure

E7H08:

Which of the following components can be used to reduce thermal drift in crystal oscillators?

1. NP0 capacitors
2. Toroidal inductors
3. Wirewound resistors
4. 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?

1. A direct digital synthesizer
2. A hybrid synthesizer
3. A phase-locked loop synthesizer
4. A diode-switching matrix synthesizer

E7H10:

What information is contained in the lookup table of a direct digital synthesizer (DDS)?

1. The phase relationship between a reference oscillator and the output waveform
2. Amplitude values that represent the desired waveform
3. The phase relationship between a voltage-controlled oscillator and the output waveform
4. Frequently used receiver and transmitter frequencies

E7H11:

What are the major spectral impurity components of direct digital synthesizers?

1. Broadband noise
2. Digital conversion noise
3. Spurious signals at discrete frequencies
4. 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?

1. Provide the crystal with a specified parallel inductance
2. Provide the crystal with a specified parallel capacitance
3. Bias the crystal at a specified voltage
4. 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?

1. Use a GPS signal reference
2. Use a rubidium stabilized reference oscillator
3. Use a temperature-controlled high Q dielectric resonator
4. All these choices are correct

E7H14:

What is a phase-locked loop circuit?

1. An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator
2. An electronic circuit also known as a monostable multivibrator
3. An electronic servo loop consisting of a phase detector, a low-pass filter, a voltage-controlled oscillator, and a stable reference oscillator
4. 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?

1. Wide-band AF and RF power amplification
2. Comparison of two digital input signals, digital pulse counter
3. Photovoltaic conversion, optical coupling
4. Frequency synthesis, FM demodulation