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. Reduces A/D sample rate from the oversampled rate to nominal rate by turning series of one- bit samples into a series of multi- bit PCM samples; (ex. => 2.8MHz sample rate converted to 44.1kHz and simultaneously converts 1-Bit samples to multi- bit);






2. Used as the main disc from which other discs are made; Composed of ground glass with a very fine photoresistor layer; An imaging laser burns pit and land patterns in preparation for duplication






3. The amount of energy at each wavelength






4. Decibels Full Scale






5. The loudest point of a Full Scale system






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






7. A network communications protocol that specifies how machines will exchange data; Uses a broadcast system in which one machine transmits its message on the communication medium and the other machines listen for messages directed to them






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






9. Very quiet digital amplifier that produces a series of output pulses with the audio signal coded the same as the width of the output pulses; Pulses are used to represent wave forms and are either on or off; Intense signals have long pulses with short






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






11. Allows for an internal sample rate at multiples of the input and output rates; Alleviates the need for steep 'brickwall' filters; Often combined with internal '1- bit' processing; Increases smoothing effect






12. Represents the amplitude component of the digital sampling process; Technique of incrementing a continuous analog event into a discrete set of binary digits (bits)






13. Having a repeated succession of waves or curves as in a sound waveform






14. High Pressure - Part of a longitudinal wave where the particles of the medium are close together






15. Difference in brightness between land and pit on a CD Physical Format






16. Leaving space at beginning and ending of song for data crunching during mastering; Last step in mastering process






17. Branch of psychology concerned with the subjective perception of sound






18. ADPCM; Pulse code modulation that produces a digital signal with a lower bit rate than standard PCM; Records only the difference between samples






19. The number of compressions or rarefactions in one second; The higher the frequency the more compressions & rarefactions per second; Measured in Hertz






20. (Time Based) Frequency: Aliasing; Anti-Aliasing Filter; Sample Rate; Nyquist Limit






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






22. Smallest interval measurable by a scientific instrument; Defined by bit rate (sample rate x bit depth)






23. Channels are processed one at a time and the results are stored on multiple CPU buffers that alternately send data as DAW requests the data for playback; First few seconds are relayed to the buffer prior to processing and playback and it continuously






24. Deviation from a normal - steady pulse or tick of a clock that contributes to misrepresentation of a signal; Result of small timing irregularities that become magnified during the transmission of digital signals as the signals are passed from one dev






25. 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






26. VBR; Most common & best data reduction technique; Codecs that encode data by determining how dense or sparse areas of the audio are; Can result in buffering issues






27. Waveform of a pure tone showing simple harmonic motion






28. 4.38 GB; SS/SL






29. 1.) Bit Rate x Sample Rate (you'll get b/sec) 2.) Multiply by 60 if converting seconds to minutes 3.) Divide by 8 to convert bits to Bytes and get B/min 4.) Divide by 1 -024 to get KB/min and keep doing it until you get desired bit rate specification






30. 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'






31. 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






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






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






34. Number of bits used to represent the smallest unit of information in an audio file; Greater bit depth = better quality audio






35. A time regulator that makes all samples and bits to align when working with interconnected digital devices; Basically a signal that all of the digital devices refer to when operating.






36. Same as 'aliasing'






37. Increases D/A sample rate from nominal rate to oversampling rate by turning series multi- bit PCM samples into 1- bit samples; (ex. => 44.1kHz sample rate converted to 2.8MHz and simultaneously converts multi- bit samples to 1- bit); Low Pass Filter






38. The art of deciding where to place a processor in signal flow based on how that processor will be influenced by the other processors in the path






39. (Amplitude Based) Amplitude: Voltage; Quantization; Bit Depth; Quantization Intervals; Quantization Noise; [Signal:Quantization Noise Ratio]; Dither; Dynamic Range






40. Data reduction technique that selectively removes original information in order to significantly reduce the file size; Some data is lost; Files can be reduced up to 99% in size (90% with no perceived sound quality loss); Bit rate effects the perceive






41. Voltage -> Dither -> Anti-Aliasing (Low Pass Filter) -> Sample & Hold Circuit -> Successive Approximation/Quantizer --) 100111010 (PCM Audio File)






42. Defines the number of sample per second taken from a continuous signal to make a discrete signal; Governs the frequency response of digital audio






43. Used when the reference pressure of a sound is 20 microPa (0.00002); Sound Pressure Level; Measure of amplitude






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






45. MPEG; Standardizing body of audio coding






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






47. Unit of measurement that is equal to one millionth of a meter






48. Mixing data and control characters in a single operation






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






50. Sony and Philips optical disc format; Utilizes sigma delta DSD to offer higher resolution; 1- bit; 2.8224 MHz; 6-Channel