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






2. The frequency range that is allowed through a filter






3. The difference between the analog value and the approximated digital value due to the 'rounding' that occurs while converting the analog signal to digital






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






5. Allowance of noise floor below that which is required for the final product






6. The continuous loss of signal strengths as a signal travels through a medium






7. A method of representing real numbers using a mantissa and an exponent






8. Measuring equipment in A/D conversion that processes voltage and provides a value for that voltage






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






10. 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






11. Governs the frequency response of a digital system; The highest- frequency component that can be captured with a sampling rate; always 1/2 of sampling rate; Also called the limiting frequency






12. A digital filter's time domain output sequence when the input is a single sample is input






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






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






15. 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






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






17. 'Capturing' part of digital audio; Never captures a signal perfectly






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. Reference voltage determined by summing the voltage values of a predetermined number of previous samples; Numbers of 1 in row = waveform peak; Numbers of 0 in row = waveform trough; Basis of Sony's Direct Stream Digital (DSD)






20. Lossless Format; Can hold up to 25GB on a single- layer disc and 50GB on a dual- layer disc






21. Sum of all harmonics; Sum of sine and cosine waves which have frequencies f - 2f - 3f - 4f...






22. 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






23. Have odd numbered harmonics






24. Sample Rate x Bit Depth x # of Channels






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






26. Psychoacoustic model of data reduction used for general audio compression that aims to transmit only features perceptible to the human ear; Useful for mastering streaming media






27. Mixing data and control characters in a single operation






28. 12.33 GB; DS/ML






29. 4.38 GB; SS/SL






30. 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






31. Found that aliasing was always a problem no matter how fast you sample; Less data recorded but more accurate; 2 samples per wave length.






32. The loudest point of a Full Scale system






33. 16-Bit; 44.1 kHz; PCM; Stereo






34. As sample rate is increased more room is created for a smoother slope of the attenuation band because Nyquist limit extends well beyond range of hearing with each increase






35. Subtract place values from the decimal number and place ones or zeros in the correct places






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






37. 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






38. Accuracy with which an electronic system reproduces the sound or image of its input signal






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






40. Ratio of magnitude of the analytical signal to the magnitude of the background noise signal






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






42. MPEG; Standardizing body of audio coding






43. Stores only one copy of a stereo signal and assigns it to both channels in order to save 50% of original bandwidth






44. Process of building a complex tone by starting with the fundamental frequency and adding pure tone harmonics






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






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






47. The process of reducing the space required to store data by efficiently encoding the content.






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






49. Signal conversions are mixed with playback tracks resulting in near-zero latency






50. Number or variable that represents the number of times the base of a power is used as a factor; Defines magnitude