EECS 1520 Midterm 2 Test Questions with Correct Answers Latest Update 2025-2026
Sound waves are a form of: - Answers Analog
Electrical signals are a form of: - Answers Digital
What is microphone also known as: - Answers A transducer
What converts sounds waves to electrical signals? - Answers A microphone (transducer)
What do speakers do? - Answers Convert digital into sound waves
What is the term for converting analog into digital? - Answers Sampling
What is the term for the production of sound waves? - Answers Synthesis
Define this formula: S(t) = 𝑎 sin(2 𝜋 𝑓 (𝑡 − 0)) - Answers a = amplitude
f = frequency
t = time (final)
0 = phase (time shift or starting time)
What is the unit for amplitude? - Answers dB (decibel)
What is the unit for frequency? - Answers Hz (hertz)
Amplitude is known as - Answers Intensity (loudness)
Frequency is known as - Answers Perceived pitch
The average human hearing frequency in Hz is - Answers 16 Hz to 20 kHz
Sampling/samples are known as - Answers Measurements
What is sampling rate? - Answers It is a fixed rate
Increased sampling rate means - Answers Larger file and better quality
Decreased sampling rate means - Answers Smaller file and lower quality/inaccurate
Who gave the idea of sample interval < half period? - Answers Nyquist-Shannon
Higher bit depth means: - Answers A more accurate sample
What is known to use <8 bits - Answers To record physical processes (not used to record sound)
such as blood pressure, heartbeat, motion due to walking/running
What is known to use 8 bits - Answers Cellular phones / telephones when speaking to each
, other
What is known to use 16 bits - Answers Most high-quality sound like CDs, DAT, MP3, movie
audio tracks
What is known to use 24+ bits - Answers Really high quality/dynamic range movies such as DVD
-Audio, DTS (used in studios to edit songs by singers)
Sampling rate + Bit depth = - Answers Bit rate
Higher bit rate = - Answers Larger file size + better quality
Who recommends a sampling rate > 2 x max frequency for accurate reproduction? - Answers
Nyquist-Shannon (his theory at least)
What is the CD-quality Audio Industry Standard? - Answers 16 bits bit depth + 44.1 kHz sampling
rate + 1.4M bits/sec
Calculate: What is the bit rate for a CD that consists of 16-bit bit depth (where per channel,
stereo has 2 TOTAL CHANNELS), and 44.1 kHz of the sampling rate? - Answers 16 x 44,100 x 2
= 1,411,200 bits/second
What is uncompressed audio typically saved in? - Answers .wav format
What are the two audio compression techniques? - Answers Lossless and lossy
What is lossless audio compression? - Answers Similar to text compression techniques
What is lossy audio compression? - Answers It uses psychoacoustics models (by removing
imperceptible sounds such as when the recording catches a louder sound at that specific time)
and it reduces the bit rate (lower quality)
What is Codecs - Answers A group of Compression and Decompression algorithms for audio
What does FLAC (an example of codecs) stand for? - Answers Free Lossless Audio Codec
Which codecs uses the lossless method? - Answers FLAC (typically used for archiving high
quality audio)
Which codecs uses the lossy method? - Answers MP3 and AAC
What does MP3 stand for? - Answers Moving Pictures Experts Group, Audio Layer 3
What does AAC stand for? - Answers Advanced Audio Coding
What has better perceived quality, AAC or MP3? - Answers AAC
Human retina contains light-sensitive cells for: - Answers 4 types: 1 for low-light "night" vision
Sound waves are a form of: - Answers Analog
Electrical signals are a form of: - Answers Digital
What is microphone also known as: - Answers A transducer
What converts sounds waves to electrical signals? - Answers A microphone (transducer)
What do speakers do? - Answers Convert digital into sound waves
What is the term for converting analog into digital? - Answers Sampling
What is the term for the production of sound waves? - Answers Synthesis
Define this formula: S(t) = 𝑎 sin(2 𝜋 𝑓 (𝑡 − 0)) - Answers a = amplitude
f = frequency
t = time (final)
0 = phase (time shift or starting time)
What is the unit for amplitude? - Answers dB (decibel)
What is the unit for frequency? - Answers Hz (hertz)
Amplitude is known as - Answers Intensity (loudness)
Frequency is known as - Answers Perceived pitch
The average human hearing frequency in Hz is - Answers 16 Hz to 20 kHz
Sampling/samples are known as - Answers Measurements
What is sampling rate? - Answers It is a fixed rate
Increased sampling rate means - Answers Larger file and better quality
Decreased sampling rate means - Answers Smaller file and lower quality/inaccurate
Who gave the idea of sample interval < half period? - Answers Nyquist-Shannon
Higher bit depth means: - Answers A more accurate sample
What is known to use <8 bits - Answers To record physical processes (not used to record sound)
such as blood pressure, heartbeat, motion due to walking/running
What is known to use 8 bits - Answers Cellular phones / telephones when speaking to each
, other
What is known to use 16 bits - Answers Most high-quality sound like CDs, DAT, MP3, movie
audio tracks
What is known to use 24+ bits - Answers Really high quality/dynamic range movies such as DVD
-Audio, DTS (used in studios to edit songs by singers)
Sampling rate + Bit depth = - Answers Bit rate
Higher bit rate = - Answers Larger file size + better quality
Who recommends a sampling rate > 2 x max frequency for accurate reproduction? - Answers
Nyquist-Shannon (his theory at least)
What is the CD-quality Audio Industry Standard? - Answers 16 bits bit depth + 44.1 kHz sampling
rate + 1.4M bits/sec
Calculate: What is the bit rate for a CD that consists of 16-bit bit depth (where per channel,
stereo has 2 TOTAL CHANNELS), and 44.1 kHz of the sampling rate? - Answers 16 x 44,100 x 2
= 1,411,200 bits/second
What is uncompressed audio typically saved in? - Answers .wav format
What are the two audio compression techniques? - Answers Lossless and lossy
What is lossless audio compression? - Answers Similar to text compression techniques
What is lossy audio compression? - Answers It uses psychoacoustics models (by removing
imperceptible sounds such as when the recording catches a louder sound at that specific time)
and it reduces the bit rate (lower quality)
What is Codecs - Answers A group of Compression and Decompression algorithms for audio
What does FLAC (an example of codecs) stand for? - Answers Free Lossless Audio Codec
Which codecs uses the lossless method? - Answers FLAC (typically used for archiving high
quality audio)
Which codecs uses the lossy method? - Answers MP3 and AAC
What does MP3 stand for? - Answers Moving Pictures Experts Group, Audio Layer 3
What does AAC stand for? - Answers Advanced Audio Coding
What has better perceived quality, AAC or MP3? - Answers AAC
Human retina contains light-sensitive cells for: - Answers 4 types: 1 for low-light "night" vision
