Appendix B: Chapter Quiz Questions

This appendix gathers every chapter quiz into one place, so you can review the full set without jumping between chapters. Each chapter contributes five questions, drawn from the interactive end-of-chapter quizzes. Read through them as a self-test, then check yourself against Appendix C, which gives the correct option and a short explanation for every question.

Chapter 1: Signal Generation Basics

  1. A waveform is best described as a record of what?
    1. How current divides across a circuit
    2. How voltage changes over time
    3. How power is distributed across frequency
    4. How impedance varies with temperature
  2. The period of a periodic waveform is equal to which of the following?
    1. The amplitude times the frequency
    2. The peak-to-peak voltage divided by two
    3. One divided by the frequency
    4. The phase expressed in radians
  3. What fundamentally separates an arbitrary waveform generator from a function generator?
    1. The AWG can reach higher voltages
    2. The AWG plays voltage samples from memory instead of using fixed shape circuits
    3. The function generator cannot produce a sine wave
    4. The AWG has no digital-to-analog converter
  4. Which task requires an arbitrary waveform generator rather than a basic function generator?
    1. Producing a clean 1 kHz sine tone
    2. Outputting a fixed-frequency square clock
    3. Replaying a real-world signal captured on an oscilloscope
    4. Generating a simple linear ramp
  5. Direct digital synthesis (DDS), which arrived in the 1970s and 1980s, generates a signal by doing what?
    1. Tuning an analog oscillator with a variable resistor
    2. Stepping through a stored table of sine values with a digital accumulator and a DAC
    3. Amplifying broadband noise through a narrow filter
    4. Mixing two crystal oscillators to produce a beat frequency

Chapter 2: How an AWG Works

  1. An AWG stores a 2,000-sample waveform and clocks it out at 200 MSa/s, looping continuously. What is the output frequency of the repeating waveform?
    1. 10 kHz
    2. 100 kHz
    3. 400 kHz
    4. 200 MHz
  2. What does the reconstruction (anti-imaging) filter remove from the DAC output?
    1. DC offset added by the output amplifier
    2. Quantization noise from the finite bit depth
    3. The high-frequency spectral images created by sampling, leaving the smooth waveform
    4. Glitch energy generated inside the DAC core
  3. Which statement best distinguishes direct digital synthesis (DDS) from true arbitrary playback?
    1. DDS uses a phase accumulator and lookup table for fine-resolution tones; true arb reads sequential memory point by point
    2. DDS requires deeper memory than true arbitrary playback
    3. True arb can only produce sine waves, while DDS produces any shape
    4. DDS works only above 1 GHz, true arb only below
  4. Why is DAC quality usually the dominant factor in an AWG's output fidelity?
    1. The DAC sets the maximum memory depth of the instrument
    2. The DAC is the digital-to-analog border, so its resolution, update rate, and glitch energy set the noise floor and spurious performance
    3. The DAC determines the trigger latency
    4. The DAC controls the 50-ohm output impedance
  5. A bench instrument offers standard sine, square, and ramp shapes plus 256K points of arbitrary memory at a moderate sample rate. Which family does it belong to?
    1. A pure function generator with no arbitrary capability
    2. An arbitrary function generator (AWFG)
    3. A true high-speed AWG with gigasample memory
    4. A digital pattern generator

Chapter 3: Key Specifications

  1. An AWG runs at a 2 GSa/s update rate. Ignoring practical filter roll-off, what is the highest frequency it can in principle represent?
    1. 2 GHz, equal to the sample rate
    2. 1 GHz, half the sample rate (the Nyquist limit)
    3. 4 GHz, twice the sample rate
    4. 500 MHz, one quarter of the sample rate
  2. Using the ideal converter relation SNR = 6.02N + 1.76 dB, roughly how much dynamic range does each added bit of DAC resolution buy?
    1. About 1.76 dB per bit
    2. About 3 dB per bit
    3. About 6 dB per bit
    4. About 20 dB per bit
  3. A generator stores 1,000,000 points and plays them at 20 GSa/s. How long is the unique playback before the waveform must repeat or refill?
    1. 50 microseconds
    2. 20 microseconds
    3. 1 millisecond
    4. 500 nanoseconds
  4. An AWG output stage has roughly 1 GHz of analog bandwidth. Using the rule of thumb, what is its approximate rise time?
    1. 35 ps
    2. 350 ps
    3. 3.5 ns
    4. 35 ns
  5. What does SFDR (spurious-free dynamic range) specifically measure?
    1. The total integrated noise power across the whole band
    2. The amplitude gap, in dBc, between the fundamental and the single largest spur, harmonic or not
    3. The number of effective bits the DAC delivers at high frequency
    4. The short-term frequency instability of the sample clock

Chapter 4: Sampling Theory and Signal Fidelity

  1. An AWG updates its DAC at a sample rate Fs. According to the Nyquist-Shannon sampling theorem, the highest frequency component it can represent must be:
    1. Strictly less than Fs/2, the Nyquist frequency
    2. Exactly equal to Fs
    3. Strictly less than Fs, the full sample rate
    4. Equal to twice Fs
  2. A 600 MHz frequency component is generated on a system sampling at 1000 MS/s. Where does it actually appear in the first Nyquist zone?
    1. It stays at 600 MHz with no penalty
    2. It aliases to 400 MHz (Fs minus the tone)
    3. It is fully removed by the reconstruction filter
    4. It appears at 1600 MHz only
  3. Because a DAC holds each sample value until the next clock edge (a zero-order hold), the output amplitude at the Nyquist frequency is attenuated by approximately:
    1. 0 dB, the hold has no effect
    2. 1.76 dB
    3. 3.9 dB relative to DC
    4. 6 dB per bit
  4. What is the primary benefit of oversampling or digital interpolation in an AWG?
    1. It increases the DAC's bit depth automatically
    2. It pushes the spectral images higher in frequency so a gentler reconstruction filter can be used
    3. It eliminates the need for any output filter
    4. It removes quantization noise entirely
  5. Why is dither added to a signal before quantization?
    1. To boost high-frequency amplitude lost to the zero-order hold
    2. To increase the number of DAC output levels
    3. To randomize quantization error so periodic spurs spread into a smooth noise floor
    4. To raise the sample rate of the DAC

Chapter 5: Creating and Sequencing Waveforms

  1. When you import a scope capture into an AWG and play it back, why does setting the sample rate correctly matter?
    1. A data file has no inherent time axis, so the AWG plays the samples at its own clock; a mismatch shifts every frequency in the signal.
    2. Imported files always replay at exactly the capture rate regardless of the AWG clock.
    3. Sample rate only affects amplitude, not timing.
    4. The AWG automatically detects the capture rate from the file contents.
  2. What is the main advantage of sequencing segments over storing one giant waveform?
    1. It increases the DAC's vertical resolution.
    2. A repeated segment is stored once and looped, so memory is reused and the scenario can react to triggers and events.
    3. It removes the need to set a sample rate.
    4. It guarantees seamless loop points automatically.
  3. An instrument has a waveform granularity of 16 samples. Which buffer length is legal?
    1. 1000 samples
    2. 1004 samples
    3. 1008 samples
    4. 1010 samples
  4. Why does a looped waveform with a fractional number of cycles in the buffer produce spurs?
    1. Fractional cycles raise the average power of the signal.
    2. The end phase does not match the start phase, so the wrap forces a step discontinuity that is wideband and repeats every loop.
    3. Fractional cycles cause the DAC to clip.
    4. The instrument refuses to loop and outputs DC instead.
  5. A captured transient cannot be made to hold an integer number of cycles. What is the practical fix to reduce the loop glitch?
    1. Increase the amplitude until the step disappears.
    2. Lower the sample rate until the file fits.
    3. Apply a window that tapers the start and end toward a common value so the junction no longer takes a hard step.
    4. Store the waveform twice back to back.

Chapter 6: Modulation and Signal Scenarios

  1. In amplitude modulation, what happens when the modulation index m exceeds 1.0?
    1. The carrier frequency doubles
    2. Overmodulation occurs and the envelope clips through zero, distorting the recovered message
    3. The signal becomes a pure FM waveform
    4. Nothing changes; the index has no upper limit
  2. Which three parameters fully define a linear frequency modulated (LFM) chirp?
    1. Amplitude, phase, and duty cycle
    2. Modulation index, deviation, and carrier power
    3. Start frequency, stop frequency, and sweep duration
    4. Pulse width, rise time, and PRF
  3. When using two synchronized AWG channels for IQ vector generation, what does the external IQ modulator do?
    1. It computes the inverse FFT of the subcarriers
    2. It mixes I and Q against a local oscillator and its 90-degree-shifted copy, then sums them into one RF output
    3. It adds Gaussian noise to set the SNR
    4. It stores the recorded RF environment for replay
  4. A 16-QAM constellation appears rotated and sheared even though the computed samples are correct. What is the most likely cause?
    1. The waveform memory is too small
    2. Gain, delay, or phase mismatch between the I and Q channels in the analog path
    3. The modulation index is set to zero
    4. The DAC resolution is too high
  5. Why is replaying a recorded RF environment from AWG memory valuable for receiver testing?
    1. It eliminates the need for any digital modulation
    2. It lowers the required DAC sample rate to zero
    3. It makes a one-off field failure into a repeatable test case you can run against firmware revision after revision
    4. It automatically corrects multipath in the receiver

Chapter 7: Triggering, Synchronization, and Multi-Channel

  1. What is the purpose of trigger holdoff?
    1. It increases the output amplitude after a trigger
    2. It is a blanking interval after a valid trigger during which further triggers are ignored, preventing double-triggering on a noisy or bouncing edge
    3. It selects whether the instrument triggers on the rising or falling edge
    4. It sets the number of cycles played in burst mode
  2. In which trigger mode does the AWG play its waveform exactly once on each trigger event and then return to the armed state?
    1. Continuous mode
    2. Gated mode
    3. Triggered (single-shot) mode
    4. Internal mode
  3. A marker (sync output) is most useful because it is generated from the same clock and sample stream as the analog output. What does that let it do?
    1. Replace the need for a sample clock entirely
    2. Provide a clean digital edge aligned to a precise sample position, ideal for triggering a scope or gating a device under test
    3. Increase the instrument's vertical resolution
    4. Convert the analog output into IQ baseband
  4. Why is a shared 10 MHz reference NOT the same as deterministic sample alignment between two instruments?
    1. A 10 MHz reference cannot be distributed to more than one instrument
    2. The reference disciplines frequency so the instruments do not drift, but each instrument's clock divider can come up in a different phase, so they may sit hundreds of picoseconds or a full sample apart at start
    3. A shared reference forces both instruments to use the same waveform
    4. The reference only works for analog outputs, not digital markers
  5. After establishing phase coherence across channels, what step turns a phase-coherent instrument into a phase-accurate one?
    1. Raising the sample rate until skew disappears
    2. Switching every channel to continuous mode
    3. Calibrating skew: output the same signal on all channels, measure the offset on a fast scope, and apply a per-channel programmable delay until they align
    4. Removing the shared reference so the channels run independently

Chapter 8: Applications

  1. In a pulsed radar scenario, what does the linear frequency modulated (LFM) chirp inside each pulse provide?
    1. It lowers the carrier frequency to baseband
    2. It supplies pulse-compression range resolution, with compression gain tied to the time-bandwidth product
    3. It removes the need for any pulse repetition interval
    4. It eliminates receiver noise automatically
  2. Why does electronic warfare scenario generation place such a heavy demand on AWG memory depth?
    1. Because each pulse needs its own DAC
    2. Because a long, dense threat environment must play without an audible repetition the receiver can lock onto
    3. Because memory sets the carrier frequency
    4. Because low noise is only available in large memories
  3. Which specification most quietly limits two-qubit gate fidelity in a multi-channel quantum control setup?
    1. Peak sample rate
    2. Total waveform memory
    3. Channel-to-channel timing skew
    4. Output connector type
  4. What is the value of impaired-signal generation when testing a wireless or satcom receiver?
    1. It guarantees the receiver passes every standard
    2. It reveals how the receiver copes with known, deliberate impairments like IQ imbalance, phase noise, or fading
    3. It reduces the required sample rate to zero
    4. It replaces the need for a clean reference signal
  5. In semiconductor automated test equipment (ATE), which AWG characteristic translates most directly into production cost?
    1. The maximum output voltage
    2. The number of front-panel buttons
    3. Waveform settling and switching time between test segments, multiplied by part volume
    4. The color of the display

Chapter 9: Selecting an Arbitrary Waveform Generator

  1. What should drive your AWG selection before you open any datasheet?
    1. The price ceiling set by your budget
    2. A description of the worst-case signal you must produce
    3. The brand the rest of the lab already owns
    4. The instrument with the highest sample rate available
  2. If the highest meaningful frequency in your signal is 500 MHz, what is a sensible practical sample-rate target?
    1. Exactly 1 GS/s, the Nyquist minimum
    2. 500 MS/s, matching the frequency
    3. 1.25 to 2.5 GS/s, for headroom above Nyquist
    4. 20 GS/s, because more is always better
  3. Your output shows soft, rounded edges and amplitude that droops at the top of the band. Which specification is most likely the limit?
    1. Memory depth
    2. Analog bandwidth
    3. Channel count
    4. Sample rate is too high
  4. When does 16-bit resolution matter more than raw sample rate?
    1. When generating multi-GHz carriers by direct synthesis
    2. When you must reproduce a small signal cleanly beside a much larger one
    3. When the only goal is the fastest possible edges
    4. When memory is the binding constraint
  5. Why can a mid-tier AWG with strong sequencing beat a top-tier instrument with deep flat memory?
    1. Sequencing increases the DAC resolution
    2. Most real scenarios repeat, so storing unique segments with loop counts uses far less memory than a flat waveform
    3. Sequencing removes the need for analog bandwidth
    4. Flat memory cannot be streamed