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. Digital (binary) measurements of how long each pulse is either on or off; Width of increasing voltage or decreasing voltage is assigned a 1 or 0 respectively






2. Industry Standards: -6 dB Peak = -20 RMS Meter






3. Measure of sound pressure over the frequency spectrum - for which a listener perceives a constant loudness when presented with pure steady tones






4. Signal voltage is relayed to a register from sample- and - hold circuit; Holds reference frequencies in binary form that decrease in value; Finds approximated value & assigns binary number accordingly






5. 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






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






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






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






9. Waveform of a pure tone showing simple harmonic motion






10. MPEG; Standardizing body of audio coding






11. 7.95 GB; SS/DL






12. 4.38 GB; SS/SL






13. Method of sampling data at a higher resolution (higher sample rate) as a means of reducing harmonic content during D/A conversion; (x2) oversampling gets rid of all odd harmonic content






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






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






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






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






18. A drive that can read and write on optical media that hold up to 50 GB on two layers; 24- bit/96 kHz for 8-Channel; 24- bit/192 kHz for 6-Channel






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






20. 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)






21. Samples are duplicated and the playback sampling rate correspondingly increased; Significantly raises the Nyquist limit to a range well beyond human hearing; Processing 'pushes' the distortion resulting from quantization error into these higher frequ






22. French mathematician that noted that any complex sound can be broken down into a series of component pure tones






23. 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.






24. 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






25. 8.75 GB; DS/SL






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






27. 15.9 GB; DS/DL






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






29. Each bit in the bit depth is equal to a _____ increase in dynamic range






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






31. RAM holds in memory audio data before it is transferred to the memory controller; Certain amount of data is processed before large amounts of data are streamed to prevent latency






32. Very selective method of lowering buffer levels by halting different levels of audio processing






33. 1.) Taking a series of evenly- spaced measurements 2.) Signal contains no frequency components higher than half the sample rate






34. CobraNet; EtherSound; Dante; AVB (currently under development)






35. Six channel (five speakers and one subwoofer for bass) digital surround sound system by Dolby






36. EBU






37. 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






38. Take up half as many bits (50%); Algorithm can keep same quality by lossing the stereo track






39. 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);






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






41. Circuit that interprets the meaning of the symbols as they were chosen and arranged by the encode






42. 8- in/8- out on one cable; 25- pin D- sub connector






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






44. AES






45. 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






46. Roughly around 1 -130 ft/s






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






48. 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






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






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