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. 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






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






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






4. Sample Rate x Bit Depth x # of Channels






5. Eight channel digital surround sound system by Dolby






6. 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






7. 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






8. Twice as many samples as the highest frequency at minimum; Sampling rate totally controls frequency response






9. 16-Bit; 44.1 kHz; PCM; Stereo






10. 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






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






12. 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






13. 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






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






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






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






17. Data reduction technique that does not effect quality of original audio; No effect on original quality; Typically around 50% reduction; Exact reconstruction of digital code for the audio signal






18. 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)






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






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






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






22. Same as 'aliasing'






23. 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






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






25. 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)






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






27. Process that begins with a fast FFT analysis of the spectra of two input signals - then the multiplication of like frequencies - and IFFT to finalize the process






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






29. Splits the input signal and mixes it with an analog copy so that no latency is present






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






31. Specific set of instructions for carrying out a data reduction technique that determines how to 'save' binary data information efficiently






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






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






34. Cable used to transmit data; Inner cable is surrounded by a plastic insulator - which is surrounded by a wire mesh conductor that insulates the internal signal wire from external interference and an outer casing that functions as a ground






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






36. 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






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






38. 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






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






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






41. Data is transmitted over fiber optic lines; Uses a TOSLINK connecter instead of an RCA type; Can transmit multi- channel audio; Not susceptible to ground hum and loops; Able to support far higher rates of data transfer over greater distances than coa






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






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






44. 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






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






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






47. 1st commercially successful AoE format for the transmission of digital audio - video - and control signals over 64- channel 100Mbps Ethernet networks






48. 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






49. 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






50. 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