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Digital Audio

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
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  • Match each statement with the correct term.
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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. Roughly around 1 -130 ft/s






2. Also known as equal loudness curves; Graph that indicates the average ear sensitivity to different frequencies at different SPL levels (as volume increases - these curves flatten out)






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






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






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






6. 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






7. In order to play multiple channels at one time data is buffered as read to disk; Latency happens between play command & beginning of playback






8. 12cm plastic disc; 1.2mm thick; One- sided; Red Laser; 1.6 microns between tracks; 125 nanometer pits






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






10. Contains all even and odd harmonics associated with a fundamental tone - making it a rich source for modeling other sounds; Amplitude of each overtone decreases exponentially as a ratio of the harmonic's frequency to that of the fundamental






11. MPEG; Standardizing body of audio coding






12. 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






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






14. Softest sound that can be heard by the average human ear (0 dB)






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






16. Fractional part of a floating- point number; Also called the mantissa; Defines precision






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






18. The loudest point of a Full Scale system






19. 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






20. Sample Rate x Bit Depth x # of Channels






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






22. The act of a frequency swinging back and forth with a steady - uninterrupted rhythm






23. 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






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






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






26. 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






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






28. More accuracy in low amplitudes and less in higher amplitudes






29. 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






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






31. 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






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






33. The ability of a digital system to perform complex DSP without running into problems with overflow or loss of resolution






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






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






36. Have odd numbered harmonics






37. 1st commercially successful AoE format for the transmission of digital audio - video - and control signals over 64- channel 100Mbps Ethernet networks






38. 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






39. 12.33 GB; DS/ML






40. Waveform of a pure tone showing simple harmonic motion






41. 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






42. Electromagnetic receptor that detects the radiation known as visible light






43. 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






44. Anytime bit depth is reduced the gap gets bigger so more dithering is required






45. Describes various optical disc characteristics including the size and shape of the disc - the size of pits - the speed at which the disc spins - and a multitude of aspects regarding the specifications of the player itself






46. Apple Lossless; Windows Media Lossless; DTS HD Master Audio; Dolby True HD; FLAC






47. Eight channel digital surround sound system by Dolby






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






49. 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






50. 15.9 GB; DS/DL