Exam 3

Question 1

What is a complex wave?

Answer 1

Any sound wave that is not sinusoidal (sine wave).

Question 2

Define periodic sound waves.

Answer 2

A wave with a repeating, continuous pattern characterized by a specific wavelength and frequency.

Question 3

What are aperiodic sound waves?

Answer 3

A sound or signal that doesn’t repeat itself in a regular or predictable pattern, lacking a defined period or frequency, and often perceived as noise.

Question 4

What is the fundamental frequency?

Answer 4

The lowest frequency which is produced by the oscillation of the whole of an object, as distinct from the harmonics of higher frequency.

Question 5

Define harmonics.

Answer 5

Frequencies that are integer multiples of a fundamental frequency, forming a series of waves that are related to the fundamental frequency.

Question 6

What are overtones?

Answer 6

A frequency greater than the basic frequency of a sound.

Question 7

Define partials.

Answer 7

The individual frequency components that make up a complex sound, including the fundamental frequency and any overtones, which are also called harmonics.

Question 8

What is a waveform?

Answer 8

A time domain representation of sound.

Question 9

What does the amplitude spectrum display?

Answer 9

The amplitude and frequency of a signal.

Question 10

A spectra consists of?

Answer 10

Amplitude Spectrum
- Line spectrum
- Continuous spectrum

Question 11

What is a phase spectrum?

Answer 11

A graph that shows starting phase in degrees on the y-axis, with frequency on the x-axis.

Question 12

Amplitude Spectrum

Answer 12

The frequency domain representation. The graph displays amplitude and frequency. Vertical lines show the amplitude for each frequency component

Question 13

Line/Continuous Amplitude Spectra

Answer 13

Line spectra represents a signal as discrete frequencies (harmonics/overtone)
Continuous spectrum represents a signal as a continuous range of frequencies, often associated with noise

Question 14

List the types of complex sound waves.

Answer 14

• Sawtooth
• Square
• Triangular
• Pulse train
• Single pulse
• White Noise

Question 15

What characterizes a sawtooth wave?

Answer 15

A complex periodic wave with odd and even harmonics and amplitude decreases as the harmonic number increases.
-6 dB per octave

Question 16

Square Wave

Answer 16

Odd harmonics only
Some slope of amplitude reduction
-6 dB per octave

Question 17

Triangular Wave

Answer 17

Odd Harmonics Only
Greater slope of amplitude reduction
-12 dB per octave

Question 18

Interval Duration of Pulse Train Wave

Answer 18

Defines the period and calculates the pulse repetition frequency

Question 19

Pulse Duration in a Pulse Train

Answer 19

Determines the null frequencies

Question 20

Single Pulse

Answer 20

Can’t be periodic and their is no interval duration (period is essentially infinity).
Comtinous amplitude spectrum

Question 21

What is white noise also known as?

Answer 21

Gaussian noise.

Question 22

True or False: White noise is a complex periodic wave.

Answer 22

False. It’s a complex aperiodic wave

Question 23

What does the signal-to-noise ratio represent?

Answer 23

The relation between the signal level and the noise level.

Question 24

What does a positive signal-to-noise ratio indicate?

Answer 24

A higher signal level compared to the noise level.

Question 25

Define resonance.

Answer 25

The natural frequency at which a cavity vibrates.

Question 26

What is the difference between free and forced vibration?

Answer 26

* Free vibration: oscillates at its natural frequency without external forces * Forced vibration: driven by an external force to vibrate at the frequency of that force

Question 27

Natural Frequency

Answer 27

Natural frequency is an inherent property of a system, the frequency at which it oscillates without external forces

Question 28

Resonant Frequency

Answer 28

Resonant frequency is the specific frequency at which a system vibrates most strongly when driven by an external periodic force

Question 29

Center Frequency

Answer 29

Center frequency is a concept related to resonance in systems with a range of frequencies

Question 30

What is impedance?

Answer 30

The total opposition a system presents to the flow of sound energy. Consists of Resistance and Reactance

Question 31

Resistance

Answer 31

Damping

Question 32

Reactance

Answer 32

*Mass and Compliant *Compliant Dominant System *Mass Dominant System

Question 33

Admittance

Answer 33

measures the ease wuth which sound energy flows through a system, like the ear, and us the reciprocal of impedance

Question 34

What are narrowband filters?

Answer 34

Filters that allow a very specific, narrow range of frequencies to pass through.

Question 35

What are Broadband (wideband) Filters?

Answer 35

Broadband (or wideband) filters allow a broader range of frequencies to pass through

Question 36

What is the human hearing range?

Answer 36

Between 20-20,000 Hz.

Question 37

Upper Cutoff Frequencies

Answer 37

the highest frequency at which a filter or system still allows signals to pass through with relatively minimal attenuation

Question 38

Lower Cutoff Frequencies

Answer 38

The frequency below which a filter or circuit is significantly attenuates (reduces) the signal

Question 39

What is the function of a low-pass filter?

Answer 39

Allows lower frequencies to pass and rejects higher frequencies.

Question 40

What does a high-pass filter allow?

Answer 40

Higher frequencies to pass and rejects lower frequencies.

Question 41

What is the attenuation rate for band-pass filters?

Answer 41

-6 dB per octave.

Question 42

Define distortion.

Answer 42

Altered sound.

Question 43

What is frequency distortion?

Answer 43

Occurs when the amplitude response of a system changes across frequencies.

Question 44

Amplitude Distortion

Answer 44

Happening when the system limits or alters the amplitude of the signal It lessens the intensity of the waveform Maximum amplitude is not achieved or limited

Question 45

What is harmonic distortion?

Answer 45

Extra harmonics are added to the signal. % Harmonic Distortion = (Undesired Energy / Total Energy) × 100

Question 46

Linear

Answer 46

Input-output relationship is directly proportional

Question 47

Nonlinear

Answer 47

Overdriven/overloaded — response is not proportional.

Question 48

What does peak clipping refer to?

Answer 48

A type of amplitude distortion where the maximum amplitude of a waveform is cut off. Symmetrical (both peaks clipped equally) Asymmetrical (only one side clipped)

Question 49

Center Clipping

Answer 49

A type of amplitude distortion where low amplitude parts of a signal (near 0) are removed or set to zero. It creates a waveform with a “gap” in the middle, cutting out small fluctuations. It adds nonlinear distortion, introducing extra harmonics.

Question 50

Define intermodulation distortion.

Answer 50

Nonlinear distortion of a complex waveform.

Question 51

Distortion Products

Answer 51

Difference tones Summation tones

Question 52

What is dynamic range?

Answer 52

The range of amplitudes a system can process without distortion.

Question 53

What is transient distortion?

Answer 53

Distortion caused by short-duration signals or sudden changes in amplitude.

Question 54

Tone Burst

Answer 54

A sinusoidal pulse is used to study the transient response

Question 55

What is the relationship between pulse duration and spectrum width?

Answer 55

Inversely proportional — shorter pulse = wider spectrum.

Question 56

What happens to distortion with longer rise/fall times?

Answer 56

Less distortion; narrow

Question 57

What happens to distortion with shorter rise/fall times?

Answer 57

More distortion; wide