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WorksheetsAudio Fundamentals
Total questions: 15
Worksheet time: 9mins
The process of recording a sound, stored in the form of thousands of individual measurements, each at a discrete point in time, is called
Sizing
Synthesizing
Quantizing
Sampling
What is the standard range of human hearing?
2 Hz -20 Hz
2 Hz -20 kHz
20 Hz -20 kHz
20 Hz - 2 kHz
What is an audio?
Human ears convert these electrical impulses to vibrations
Sound from some object and hear by human ears
The sensation that we perceived when vibrations in the air detected by our ears
Transmitted to human brain via vibration
What is the file size of a 5 minute audio clip recorded in stereo with a sample frequency of 44∙1 kHz and a sample depth of 24 bits?
1.3 Mbytes
38 Mbytes
0.6 Mbytes
76 Mbytes
Which of these audio file formats support lossy compression?
FLAC
MP3
WAV
OggPCM
WMA
Before a sound can be digitized, it must undergo several form of energy conversions. Which of the following sequence is CORRECT?
Acoustic -> Electric -> Magnetic -> Mechanic
Acoustic -> Mechanic -> Magnetic -> Electric
Acoustic -> Magnetic -> Mechanic -> Electric
Acoustic -> Magnetic -> Electric -> Mechanic
What is frequency aliasing?
Aliasing is a common problem in signal conversion systems whose sampling rate is too slow to read input signals of a much lower frequency.
Aliasing occurs when sample a signal too fast and obtain an incorrect frequency and/or amplitude as a result.
Aliasing is an undesired effect in which the sampling frequency is too low to accurately reproduce the original analog content, resulting in signal distortion.
Aliasing is a common problem in signal conversion systems whose sampling rate is too fast to read output signals of a much lower frequency.
Quantization noise is the difference between the actual value of the analog signal, for the particular sampling time, and the nearest quantization interval value.
If voltages are actually between 0 to 1 but we have only 7 bits in which to store values, then effectively we force all continuous values of voltage into only 256 different values.
At most, it can be as much as quarter of the quantization interval.
Quantization noise decreases if the number of bits used in the digitization process are reduced.
Quantization noise increases if the number of bits used in the digitization process are reduced.
To convert audio analog signals into digital signals, which of the following steps are involved?
Pulse Code Modulation (PCM)
Sampling
Quantization
Codeword Assignment
Which of the following statements are correct about a psychoacoustic phenomenon known as Frequency Masking?
When an audio signal consists of multiple frequencies, the sensitivity of the ear changes with the relative amplitude of the signals. If the frequencies are close and the amplitude of one is less than the other close frequency, then the second frequency may not be heard. This phenomenon is known as Frequency Masking.
Frequency Masking occurs when the perception of a sound is affected and covered by another, distracting the ear from being able to clearly perceive the simultaneous sounds.
The frequency masking is caused when a low-tone sound makes the high-tone be heard difficult if there is a certain difference in tones between the two occurred at the same time.
Masking or removing low sensitive frequency component in audible band is called as frequency masking. It occurs when a sound that we can normally hear is masked by another sound with a nearby frequency.
Which of the following statements are correct about a psychoacoustic phenomenon known as Temporal Masking?
The sound occurred right after a loud sound is difficult to hear due to masking for 0.1 second even after the louder has vanished already. This is called temporal masking.
After the ear hears a loud sound, consisting of multiple frequencies, it takes a further short while before it can hear a quieter sound close in frequency. This is known as temporal masking.
Temporal masking is a frequency domain phenomenon in which a low-level signal can be rendered inaudible by a simultaneously occurring stronger signal if both signals are sufficiently close in frequency.
Temporal masking is the characteristic of the auditory system where sounds are hidden due to maskers which have just disappeared, or even after maskers which are about to appear.
An audio is sampled at 56 kHz rate. What is the maximum frequency in the input signal that can be fully recovered?
112 kHz
28 kHz
56 kHz
20 kHz
If an audio signal is 12 kHz, what is the minimum sampling rate so that this signal can be fully recovered from sampled signal?
6 kHz
10 kHz
24 kHz
36 kHz
