Amateur Extra › E7
E7 Practical Circuits
99 questions in the pool. Your exam will include 8, one from each group below.
E7A
Digital circuits: digital circuit principles and logic circuits; classes of logic elements; positive and negative logic; frequency dividers; truth tables
- E7A01Which circuit is bistable?
- E7A02What is the function of a decade counter?
- E7A03Which of the following can divide the frequency of a pulse train by 2?
- E7A04How many flip-flops are required to divide a signal frequency by 16?
- E7A05Which of the following circuits continuously alternates between two states without an external clock signal?
- E7A06What is a characteristic of a monostable multivibrator?
- E7A07What logical operation does a NAND gate perform?
- E7A08What logical operation does an OR gate perform?
- E7A09What logical operation is performed by a two-input exclusive NOR gate?
- E7A10What is a truth table?
- E7A11What does “positive logic” mean in reference to logic devices?
E7B
Amplifiers: class of operation; vacuum tube and solid-state circuits; distortion and intermodulation; spurious and parasitic suppression; switching-type amplifiers
- E7B01For what portion of the signal cycle does each active element in a push-pull, Class AB amplifier conduct?
- E7B02What is a Class D amplifier?
- E7B03What circuit is required at the output of an RF switching amplifier?
- E7B04What is the operating point of a Class A common emitter amplifier?
- E7B05What can be done to prevent unwanted oscillations in an RF power amplifier?
- E7B06What is a characteristic of a grounded-grid amplifier?
- E7B07Which of the following is the likely result of using a Class C amplifier to amplify a single-sideband phone signal?
- E7B08Why are switching amplifiers more efficient than linear amplifiers?
- E7B09What is characteristic of an emitter follower (or common collector) amplifier?
- E7B10In Figure E7-1, what is the purpose of R1 and R2?
- E7B11In Figure E7-1, what is the purpose of R3?
- E7B12What type of amplifier circuit is shown in Figure E7-1?
E7C
Filters and matching networks: types of networks; types of filters; filter applications; filter characteristics; impedance matching
- E7C01How are the capacitors and inductors of a low-pass filter Pi-network arranged between the network's input and output?
- E7C02What is the frequency response of a T-network with series capacitors and a shunt inductor?
- E7C03What is the purpose of adding an inductor to a Pi-network to create a Pi-L-network?
- E7C04How does an impedance-matching circuit transform a complex impedance to a resistive impedance?
- E7C05Which filter type has ripple in the passband and a sharp cutoff?
- E7C06What are the characteristics of an elliptical filter?
- E7C07Which describes a Pi-L network?
- E7C08Which of the following is most frequently used as a band-pass or notch filter in VHF and UHF transceivers?
- E7C09What is a crystal lattice filter?
- E7C10Which of the following filters is used in a 2-meter band repeater duplexer?
- E7C11Which of the following measures a filter's ability to reject signals in adjacent channels?
E7D
Power supplies and voltage regulators; solar array charge controllers
- E7D01How does a linear electronic voltage regulator work?
- E7D02How does a switchmode voltage regulator work?
- E7D03What device is used as a stable voltage reference?
- E7D04Which of the following describes a three-terminal voltage regulator?
- E7D05Which of the following types of linear voltage regulator operates by loading the unregulated voltage source?
- E7D06What is the purpose of Q1 in the circuit shown in Figure E7-2?
- E7D07What is the purpose of C2 in the circuit shown in Figure E7-2?
- E7D08What type of circuit is shown in Figure E7-2?
- E7D09How is battery operating time calculated?
- E7D10Why is a switching type power supply less expensive and lighter than an equivalent linear power supply?
- E7D11What is the purpose of an inverter connected to a solar panel output?
- E7D12What is the dropout voltage of a linear voltage regulator?
- E7D13Which of the following calculates power dissipated by a series linear voltage regulator?
- E7D14What is the purpose of connecting equal-value resistors across power supply filter capacitors connected in series?
- E7D15What is the purpose of a step-start circuit in a high-voltage power supply?
E7E
Modulation and demodulation: reactance, phase, and balanced modulators; detectors; mixers
- E7E01Which of the following can be used to generate FM phone signals?
- E7E02What is the function of a reactance modulator?
- E7E03What is a frequency discriminator?
- E7E04What is one way to produce a single-sideband phone signal?
- E7E05What is added to an FM speech channel to boost the higher audio frequencies?
- E7E06Why is de-emphasis used in FM communications receivers?
- E7E07What is meant by the term “baseband” in radio communications?
- E7E08What are the principal frequencies that appear at the output of a mixer?
- E7E09What occurs when the input signal levels to a mixer are too high?
- E7E10How does a diode envelope detector function?
- E7E11Which type of detector is used for demodulating SSB signals?
E7F
Software defined radio fundamentals: digital signal processing (DSP) filtering, modulation, and demodulation; analog-digital conversion; digital filters
- E7F01What is meant by “direct sampling” in software defined radios?
- E7F02What kind of digital signal processing audio filter is used to remove unwanted noise from a received SSB signal?
- E7F03What type of digital signal processing filter is used to generate an SSB signal?
- E7F04Which method generates an SSB signal using digital signal processing?
- E7F05How frequently must an analog signal be sampled to be accurately reproduced?
- E7F06What is the minimum number of bits required to sample a signal with a range of 1 volt at a resolution of 1 millivolt?
- E7F07What function is performed by a Fast Fourier Transform?
- E7F08What is the function of decimation?
- E7F09Why is an anti-aliasing filter required in a decimator?
- E7F10What aspect of receiver analog-to-digital conversion determines the maximum receive bandwidth of a direct-sampling software defined radio (SDR)?
- E7F11What sets the minimum detectable signal level for a direct-sampling software defined receiver in the absence of atmospheric or thermal noise?
- E7F12Which of the following is generally true of Finite Impulse Response (FIR) filters?
- E7F13What is the function of taps in a digital signal processing filter?
- E7F14Which of the following would allow a digital signal processing filter to create a sharper filter response?
E7G
Operational amplifiers: characteristics and applications
- E7G01What is the typical output impedance of an op-amp?
- E7G02What is the frequency response of the circuit in E7-3 if a capacitor is added across the feedback resistor?
- E7G03What is the typical input impedance of an op-amp?
- E7G04What is meant by the term “op-amp input offset voltage”?
- E7G05How can unwanted ringing and audio instability be prevented in an op-amp audio filter?
- E7G06What is the gain-bandwidth of an operational amplifier?
- E7G07What voltage gain can be expected from the circuit in Figure E7-3 when R1 is 10 ohms and RF is 470 ohms?
- E7G08How does the gain of an ideal operational amplifier vary with frequency?
- E7G09What will be the output voltage of the circuit shown in Figure E7-3 if R1 is 1,000 ohms, RF is 10,000 ohms, and 0.23 volts DC is applied to the input?
- E7G10What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 1,800 ohms and RF is 68 kilohms?
- E7G11What absolute voltage gain can be expected from the circuit in Figure E7-3 when R1 is 3,300 ohms and RF is 47 kilohms?
- E7G12What is an operational amplifier?
E7H
Oscillators and signal sources: types of oscillators; synthesizers and phase-locked loops; direct digital synthesizers; stabilizing thermal drift; microphonics; high-accuracy oscillators
- E7H01What are three common oscillator circuits?
- E7H02What is a microphonic?
- E7H03What is a phase-locked loop?
- E7H04How is positive feedback supplied in a Colpitts oscillator?
- E7H05How is positive feedback supplied in a Pierce oscillator?
- E7H06Which of these functions can be performed by a phase-locked loop?
- E7H07How can an oscillator's microphonic responses be reduced?
- E7H08Which of the following components can be used to reduce thermal drift in crystal oscillators?
- E7H09What type of frequency synthesizer circuit uses a phase accumulator, lookup table, digital-to-analog converter, and a low-pass anti-alias filter?
- E7H10What information is contained in the lookup table of a direct digital synthesizer (DDS)?
- E7H11What are the major spectral impurity components of direct digital synthesizers?
- E7H12Which of the following ensures that a crystal oscillator operates on the frequency specified by the crystal manufacturer?
- E7H13Which of the following is a technique for providing highly accurate and stable oscillators needed for microwave transmission and reception?