EECS 1520 midterm 2-Questions, Answers| Newest
Update 2026/2027
Audio as a Sound Wave
microphone=transducer
converting audio sound waves (analog)-->electrical signals (digital)--> speaker sound
waves(analog)
Ways of creating digital audio
- sampling
- synthesis
In a sine wave what does amplitude relate to
intensity (loudness)
In a sine wave, what does frequency relate to
perceived pitch
What is the threshold of hearing?
20 μPa
Hearing frequency limits
16 Hz - 20 kHz
-upper limit is variable (steadily decreases with age)
sampling rate/frequency
, the rate at which samples are taken (in digitizing sound)
- cannot be too fast (large file) or too low (inaccurate)
- must match original frequency
Nyquist-Shannon sampling theorem
Any continuous signal can be converted into a discrete signal with zero loss of
information/fidelity
- sample interval (frequency) > 2f for accurate rep.
- Each sample is recorded using a fixed number of bits, bit depth
• Higher bit depth means a more accurate sample
- quiet sounds better preserved
Bit rate
bit depth + sampling rate
- higher = better quality = larger file size
when was digital audio developed
1970s
when was CD released
1982
Audio Compression Techniques
Lossless, Lossy, Codecs
Lossless
Update 2026/2027
Audio as a Sound Wave
microphone=transducer
converting audio sound waves (analog)-->electrical signals (digital)--> speaker sound
waves(analog)
Ways of creating digital audio
- sampling
- synthesis
In a sine wave what does amplitude relate to
intensity (loudness)
In a sine wave, what does frequency relate to
perceived pitch
What is the threshold of hearing?
20 μPa
Hearing frequency limits
16 Hz - 20 kHz
-upper limit is variable (steadily decreases with age)
sampling rate/frequency
, the rate at which samples are taken (in digitizing sound)
- cannot be too fast (large file) or too low (inaccurate)
- must match original frequency
Nyquist-Shannon sampling theorem
Any continuous signal can be converted into a discrete signal with zero loss of
information/fidelity
- sample interval (frequency) > 2f for accurate rep.
- Each sample is recorded using a fixed number of bits, bit depth
• Higher bit depth means a more accurate sample
- quiet sounds better preserved
Bit rate
bit depth + sampling rate
- higher = better quality = larger file size
when was digital audio developed
1970s
when was CD released
1982
Audio Compression Techniques
Lossless, Lossy, Codecs
Lossless
