Test your basic knowledge |

Digital Audio

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Father of modern information theory; Solidified the Nyquist Theory by adding the concept that bits per second (binary representation of audio signals) must be at equal intervals to accurately represent data






2. Series of dots and dashes representing the letters of the alphabet; Most common letters are represented by the shortest dots and dashes; Example of entropy coding






3. Measurement at regular intervals of the amplitude of a varying waveform (in order to convert it to digital form); There must be a minimum of 2 samples for each cycle in a waveform






4. Sony sigma- delta modulation based technology that bypasses the decimation and interpolation steps found in PCM converters






5. Multi-Bit Words; (Pulse Code Modulation)






6. Low Pressure; Part in a longitudinal wave where the particles are spread apart






7. Decibels Full Scale






8. Inner ear component that attaches to the stapes and helps to decrease the amplitude of vibrations; Causes the masking phenomenon






9. Method used in digital recording and reproduction in which a signal is sampled at various points and the resulting value is translated into binary numbers






10. When recording you want the smallest buffer available; When mixing you want the largest buffer available






11. Eliminates frequencies above the Nyquist limit from becoming samples; Occurs prior to quantization






12. 12.33 GB; DS/ML






13. Removes high frequency images and noise and smoothes the stair case output coming from of the sample and hold circuit; Also called a SMOOTHING FILTER






14. Toshiba developed digital audio interface utilizes fiber optics as a transmission medium.






15. Digital Word -> Series of Resistors (each with assigned charges) -> Sample- and-Hold Circuit -> Anti-Imaging Filter (Smoothing Filter) -> Reconstructed Sample






16. Pertaining to hearing or sound; Combination of the intensity of air pressure molecules with amplitude






17. Describes acceptable data - performances both offered and essential for a disc player - and the complete user experience






18. If a signal is sampled at a rate higher than twice the highest significant signal frequency and at evenly spaced intervals - then the samples contain all the information of the original signal






19. Perceptual coding technique that uses louder sounds of a similar frequency to decide what information is to be saved during data reduction






20. Level above which audible sounds are painful (125 - 130 db)






21. ABR; Codecs that encode data by determining how dense or sparse areas of the audio are while also keeping bit rate within specified limits to avoid rebuffering






22. Improper (false) sampling of high frequencies that cause much lower frequencies to be produced when the audio is reconstructed; Foldover happens at higher frequencies as harmonics reach levels that exceed the Nyquist limit.






23. CBR; Codecs encodes data at a constant rate regardless of density of the audio file






24. Algorithm uses matrix of a mid/side microphone pair to determine a side signal & that signal is reduced then distributed as code in stereo






25. Twice as many samples as the highest frequency at minimum; Sampling rate totally controls frequency response






26. Based on psychoacoustics - these are the basis of frequency analysis for a perceptual codec;






27. Data is transmitted over fiber optic lines; Uses a TOSLINK connecter instead of an RCA type; Can transmit multi- channel audio; Not susceptible to ground hum and loops; Able to support far higher rates of data transfer over greater distances than coa






28. Single- pin RCA cable or fiber- optic TOSLINK connector used for digital transfer; 75O coaxial - 2- channel unbalanced; 'Consumer' format of AES3






29. AES






30. Joint-Stereo Technique; Since the human brain is unable to localize sounds at high frequencies well sounds above 9 kHz threshold are encoded in mono






31. High channel count; 64 channels on one cable; Coaxial cable with BNC connector or fiber optic with ST1 connector






32. Based on Full Scale (dB/FS); -6dB represents a loss of one bit so account for this when calculating






33. (AES/EBU); 110O - 2- channel balanced digital audio cable with an XLR connection; NOT a mic cable!!






34. Signal that uses variable voltage to create continuous waves resulting in an inexact transmission






35. How Loud (Y-Axis) & How Fast (X-Axis)






36. Ultra low- latency - 512- channel (on a gigabit network) - less flexible AoE format; Routed like audio cables...not network cables






37. Reduces the percieved distortion due to quantization error; Low level white noise source is introduced to make the profile of the quantization 'noise' more irregular; Useful when reducing the number of bits per word in a signal (i.e. when converting






38. The more bits allocated during quantization - the more accurate the measurement






39. The elapsed time it takes for a packet of data to arrive at its destination; Lagging or pause of an audio signal as digital processing occurs; Can be managed utilizing several forms of 'audio monitoring'






40. Digital and analog processing capability is combined on a single microchip allowing for 1- bit resolution at high sample rates






41. The difference in volume between the loudest and quietest sounds of a source






42. Discrete incremental distinctions made between the value of one sample and the next; Breaks down bit depth into a series of evenly spaced intervals






43. Unit of measurement that is equal to one billionth of a meter






44. Visual graph that shows how loud a sound is at different frequencies






45. Rate at which energy is drawn from a source that produces a flow of electricity in a circuit; Expressed in volts






46. A frequency specified for a filter (digital or electronic) the marks the point at which the frequency content of a signal is altered +/- 3dB






47. Serial Copy Management System; main difference between AES3 & S/PIDF






48. Overtones that contribute to the timbre of a sound and make up a complex waveform's physical characteristics






49. More aggressive lossy data reduction techniques that require further manipulation of the stereo field; Examples are 'Intensity' & 'M-S'






50. 15.9 GB; DS/DL