PPT 3 Flashcards
What is the basic path of a signal from input to output device?
- input
- analog-digital converter
- computer processing, storage
- digital-to-analog converter
- output device
How is an analog sound wave digitalized?
samples are taken from parts of the continuous analog wave at equal intervals and these values are output to a digital wave as discrete values
(looks like the continous spectrum vs. line spectrum graphs from physics)
What is the problem with sampling … the process of digitalizing an analog signal?
information from the intervals between signals is lost
What is the Nyquist Shannon theorem?
states that the sampling frequency (fs) should be greater than 2x the frequency of the wave being sampled to get a digitalized signal with minimal loss
fs > 2f
- also 2x the sampling time (Ts) should be less than the total time? (T)
2Ts
What is aliasing?
when the Nyquist Shannon theorem is not satisfied and therefore appreciable loss occurs and the signal is distorted by the digitalizaton process
What is Quantization?
What is the problem with it?
ordering numbers to samples
giving samples the nearest value in a set of discrete values?
- values between the steps are lost
What is quantization noise?
difference between the original and recovered signal
meaning i think… the difference between an original signal and the digitalized signal after it has been quantized?
what is sound pressure?
deviation from local pressure caused by a sound wave
what are sound intensity and pressure levels?
units?
equations?
intensity = 10 log j/j0
pressure = 20 log p/p0
both in dB
What is a fletcher munson curve?
equal loudness curves
- graph of sound pressure level vs. frequency with equiphon curves showing what dB a certain frequency must be to sound as loud as a sound from a diff. freq
