Now looking at definitions starting with letter "q"
Q (band) A unit of measurement used to measure the peak in gain around a cut-off frequency. For example, if a filter is a band reject type (i.e. it removes a designated range of frequencies) the effect is to narrow the focus of rejection. This is ideal for removing a specific frequency.
Q-factor : See Q.
Q-Lock : A brand of electronic synchronizer used for interlocking various audio and videotape recorders. The name is used generically for any such synchronizer. See BTX.
QT Quick Time an ad hoc standard created by Apple Computer that provides a scalable, cross-platform wrapper for a wide variety of media data types. QuickTime has been incorporated into the mpeg-4 standard. QuickTime is a wrapper file format.
quad track : A track negative, and any release prints made from the track negative, that contains all three digital sound formats: Dolby Digital, DTS, and SDDS, plus a standard SVA analog track.
quadraphonic : An sound system which attempts to model a live acoustic using four audio channels to give the effect of sound arriving from different parts of the listening environment. See also stereophonic, LCRS, surround-sound.
quadrature : Two signals which are 90˚ out-of-phaseout of phase with each other are said to be in quadrature. Also, a signal or function such as impedance will have a phase angle that varies with frequency or with time. The phase angle can be resolved into two components, real and imaginary, which have a 90˚ phase difference, where the imaginary part is called the quadrature part.
quadruplex recorder : A VTR recording configuration in which four heads are mounted around a wheel that turns in contact with 2" tape. This system has largely been replaced by helical scan formats.
quality factor : See Q.
quantization : (1) The representation of an analog signal by a vector of discrete values. The signal, after quantization, has a stepped shape rather than its original continuous curve, and the difference between this and the original signal is quantization error. See granulation, PCM, quantization noise. (2) A function found on sequencers and drum machines that causes notes wplayed hose start time does not correspond to the beginning of a beat at odd times to be rounded off to the nearest rhythmic value. See percentage quantization.
quantization distortion : See granulation.
quantization error : The difference between the actual analog value at the sample time and the nearest quantized (digitally encoded) value is called quantization error. At worst, the quantized value encoded will be no greater than one-half increment away from the actual analog value. Quantization error is related to the S/N ratio and the maximum number of quantization increments is related to dynamic range. See bit depth.
quantization noise : One of the types of error introduced into an analog audio signal by encoding it in digital form. The digital equivalent of tape hiss, quantization noise is caused by the small differences between the actual amplitudes of the points being sampled and the bit depth of the analog to digital converter. In the quantization of a sine wave whose frequency is a submultiple of the sampling frequency, the error will have a definite pattern which repeats at the frequency of the signal, having a frequency content consisting of multiples of this frequency, where it can be considered as harmonic distortion rather than noise. In music, however, the signal is constantly changing and no such regularity exists, resulting in quantization error, producing wideband noise, called quantization noise. See granulation.
quantization strength : See percentage quantization, quantization (2).
quantize : To produce an output in discrete steps. See quantization (2).
quantizing increments : (1) The total number of stepped levels, from noise floor to saturation, that an A/D has available for assignment of the continuously varying analog input voltage with each sample taken. For example, if each sample has a bit depth of 10, there will be 210, or 1,024, quantizing increments.
(2) The voltage or decibel difference between any particular quantizing step and the next step higher or lower. In a system with 210, or 1,024 discrete steps, if signal voltage from noise level to saturation varies from 0.0V to 1.0V, each quantizing increment will correspond to about 0.001V. See dynamic range, sound pressure level.
quarter track : Sometimes called a four-track, refers to most home-type, reel-to-reel tape recorders which use one-fourth the width of the tape for each recorded track, allowing stereo signals to be recorded in both directions, doubling the recording time. Professional stereo tape recorders use one-half the tape for each track, resulting in better quality and reduced noise level. See magnetic tape. See also half track, two-track.
quarter-wavelength rule : If a wall is a node, then the nearest other node at any frequency will be 1/2(wavelength) away from the wall. Given this, the antinode is midway between those two points, or