SHS 375 EXAM 1 PRACTICE TEST QUESTIONS AND ANSWERS 100% VERIFIED
1 keer bekeken 0 keer verkocht
Vak
SHS 375
Instelling
SHS 375
SHS 375 EXAM 1 PRACTICE TEST QUESTIONS AND ANSWERS 100% VERIFIED
Sampling - Answer- taking samples at given intervals-energy between sampling points is discarded- analog signal is made discrete in time.
Acceptable sampling rate? - Answer- Nyquist's sampling theorem, the number of samples need...
SHS 375 EXAM 1 PRACTICE TEST 2024-
2025 QUESTIONS AND ANSWERS 100%
VERIFIED
Sampling - Answer- taking samples at given intervals-energy between sampling points
is discarded- analog signal is made discrete in time.
Acceptable sampling rate? - Answer- Nyquist's sampling theorem, the number of
samples needed is TWICE the highest frequency of interest
Example acceptable sampling rate: interested in frequencies up to 5000 Hz, sampling
rate would have to be... - Answer- At least twice that, 10000 Hz
Why do we have to do sampling rate at twice the highest frequency of interest? -
Answer- to avoid aliasing
Aliasing - Answer- happens when higher frequencies appear as "fake" lower
frequencies (aka aliases). usually due to undersampling and lack of low-pass filtering
How to avoid aliasing - Answer- determine highest frequency of interest, filter energy
above the highest frequency of interest, sample the signal at a rate that is at least twice
as high as the highest frequency of interest.
Typically for speech application, recommended sampling frequency is - Answer- 22050
Hz (standard rate)
Quantization - Answer- converts the amplitude or energy level of the samples,
amplitude of signal is made discrete, continuous amplitude variations need to be
represented.
Quantum - Answer- is an increment of energy
Quantiziation rate - Answer- aka resolution, measured in bits.
*Bits are - Answer- binary digits (0,1) so a 1 bit system has 2 levels. and 8 bit system
has 256 levels. Levels equal 2 to the ^nth power (example 2^8th=256)
Analog to Digital Conversion picture - Answer- (acoustic signal)=> pre-emphasis filter=>
(pre-emphasis signal)pre-sampling low-pass filter=> (filtered
, signal)sampler=>(sequence of samples) quantizer=> (quantized samples)encoder =>
(coded item)
()= dotted lines on picture
what's involved in A-to-D and D-to-A conversion? - Answer- needs to be converted back
to analog form, final low-pass filtering is needed to smooth out the signal
To listen to a recording it needs to be in what form? - Answer- analog
time waveform presents the amplitude of the signal as ... - Answer- a function of time
(y=amplitude and x = time)
Frequency - Answer- the number of times an object vibrates through a complete cycle
per second, measured in hertz-Hz
Period - Answer- the length of one cycle
measuring frequency - Answer- 1/time in seconds Ex: duration(time) .01 frequency
would equal 100Hz because 1/.01=100
shorter period - Answer- higher frequency
Spectrum - Answer- presents amplitude of the signal as a function of frequency
(amplitude =y, frequency = x). Does NOT have a temporal component , useful for
looking at the magnitude at various frequency components at a specific time, NOT
useful to view how signal changes over time
Main types of spectra for speech analysis... - Answer- FFT, LPC
LCP - Answer- linear predictive coding
FFT - Answer- fast fourier transform
FFT components - Answer- decomposes a signal into its frequency components, is an
algorithm that greatly expedites the computations required for a more precise discrete
fourier transform, useful for looking at all frequency components, increasing the FFT
points allow more accurate display
FFT display - Answer- amplitude is on the y axis, frequency is on the x, line represents
frequency components and their amplitudes
LPC components - Answer- a method that attempts to predict upcoming speech
samples based on a weighted sum of previous samples, uses estimation based on a
vocal tract model filter, not as precise as FFT, useful for looking at spectral peaks but
not detailed frequency components, increasing the LPC order and FFT points changes
the display
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, creditcard of Stuvia-tegoed voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper Scholarsstudyguide. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €12,31. Je zit daarna nergens aan vast.
