Test your basic knowledge |

Digital Audio

Subject : engineering
Instructions:
  • Answer 50 questions in 20 minutes. 2 minutes extra for reading the instructions.
  • 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. Measure of sound pressure over the frequency spectrum - for which a listener perceives a constant loudness when presented with pure steady tones






2. Mixing data and control characters in a single operation






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






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






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






6. 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






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






8. DAW's and software must buffer when converting or bouncing and this latency can add up if not monitored






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






10. Sample Rate x Bit Depth x # of Channels






11. Root Mean Square; Refers to taking the square root of all instantaneous amplitudes; Takes the average of those squares; (-6 Peak Level is approximately equal to -20 RMS)






12. Full Scale; Type of metering that measures level in digital recording system; Recording and Mixing levels should NEVER exceed 0dB FS in digital audio or clipping will occur






13. 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






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






15. HD Audio format; Lossless Compression; 24- bit/96 kHz; 5.1 Surround or 24- bit / 192 kHz stereo sound






16. Amplitude meter that takes the square root of all instantaneous amplitudes and averages them to find a mean and squares that value; Useful with particularly complex waveforms






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






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






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






20. 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'






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






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






23. Most significant lossless coding technique in current use; Measure of disorder in which long strings of data are represented by short symbols and uses the shortest symbols to represent the most common repetitive audio data maximizing data reduction






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






25. Circuit that seizes voltage values with each tick of an A/D device's internal clock






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






27. 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






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






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






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






31. 12.33 GB; DS/ML






32. 8- in/8- out on one cable; 25- pin D- sub connector






33. The amount of energy at each wavelength






34. 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






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






36. 12cm plastic disc; 1.2mm thick; One- sided; Red Laser; 1.6 microns between tracks; 125 nanometer pits






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






38. 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.






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






40. 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






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






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






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






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






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






46. 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






47. Waveform of a pure tone showing simple harmonic motion






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






49. The frequency above or below which attenuation begins in a filter circuit






50. 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