Frequency Pitch

All of the equalization effects operate on the frequency of the sound. Frequency is a strict definition of the pitch or key in terms of the number of waves of sound per second, measured from peak to peak in a pure tone. Cycles per second are measured in Hertz (Hz). 

The scale from an EQ frequency graph compared to an 88-key keyboard and a six-string guitar. All frequencies are in Hertz (Hz). 

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Ring modulation and synchronization go beyond this to create interactive effects, in which a parameter controlling one voice also affects the sound produced by a second voice. In both cases, the special effect is created by a difference in the frequencies (pitches) of the two voices. 

Modulation Process of varying one or more properties of an electromagnetic wave. Three parameters can be altered via modulation amplitude (height), its phase (timing), and its frequency (pitch). Two common forms of radio modulation are amplitude modulation (AM) and frequency modulation (FM). 

Variable Air Flow Fans. Variable air flow fans are needed ia the process iadustry for steam or vapor condensing or other temperature critical duties. These also produce significant power saviags. Variable air flow is accompHshed by (/) variable speed motors (most commonly variable frequency drives (VFDs) (2) variable pitch fan hubs (J) two-speed motors (4) selectively turning off fans ia multiple fan iastaHations or (5) variable exit louvers or dampers. Of these methods, VFDs and variable pitch fans are the most efficient. Variable louvers, which throttle the airflow, are the least efficient. The various means of controlling air flow are summarized ia Table 3. 

Pitch The spacing of holes in a flange, or the angle of fan blades. That attribute of auditory sensation depending primarily on the frequency of the sound in terms of which sounds may be ordered on a scale extending from low to high. 

If the shafts are too far apart, the teeth mesh above the pitch line, which increases the clearance between teeth and amplifies the energy of the actual gear-mesh frequency and all of its sidebands. In addition, the load-bearing characteristics of the gear teeth are greatly reduced. Since the force is focused on the tip of each tooth where there is less cross-section, the stress in each tooth is greatly increased. The potential for tooth failure increases in direct proportion to the amount of excess clearance between the shafts. 

The Watson and Crick model for DNA as a double helix is only a generalized model to describe much more complex structures. Along with the typical double helix there exist structural elements such as supercoils, kinks, cruciforms, bends, loops, and triple strands as well as major and minor grooves. Each of these structural elements can vary in length, shape, location, and frequency. Even the simple DNA double helix can vary in pitch (number of bases per helical turn), sugar pucker conformation, and helical sense (whether the helix is left-or right-handed). 

If the SCR is placed downstream of an ESP or TSS, the design can take advantage of a cleaner flue gas. This would allow for smaller catalyst volumes using finer pitch catalyst and thus smaller SCR reactors. Problems occur when the ESP or TSS collection efficiency no longer removes the particulates from the flue gas. Not only does the SCR catalyst bed foul, requiring increased run frequency on the soot blowers, the stack opacity will also increase. 

A double metal process can be used to reduce the cell pitch and minimize parasitic resistance and capacitance, which can be critical for 4H-SiC BJTs intended for high-frequency operations. The finished structure in Figure 6.12(e) can be covered with an intermetallic dielectric layer. Via holes are then opened, and a thick metal... 

If you punch a few holes along the tube, you alter the frequencies of the standing waves that can form in the tube, with the result that different pitches are produced. This is the underlying principle in such musical instruments as flutes and saxophones. 

Although heave motions and frequencies do not Individually cause significant resonant waves they magnify the effect of the resonant waves caused by pitch or surge motions 1.e. the pitch or surge causes an out of balance system that 1s then acted on by the heave forces to magnify the fluid motion Inside the process vessel. 

This 1s a frequent occurrence since the natural longitudinal wave frequency of liquid Inside a process vessel Is typically 1n the range of 6 to 12 seconds, corresponding very closely to typical pitch and surge excitation frequencies of tankers, barges and sem1-submer 1b1es (10 - 16 seconds). 

Our experiences led to further questions Is consciousness confined to this physical body and its very limited senses Are there other, "extra" senses We know that a dog can hear sounds pitched too high for the human ear, and I know that many people can hear sounds that are inaudible to me. May it not be that there are some who are sensitive to entirely different types of frequencies that are unrecognized by most of us, and who may have "extrasensory perception" (ESP) ... 

Until now only time-frequency smearing of the audio signal by the ear, which leads to an excitation representation, has been described. This excitation representation is generally measured in dB SPL (Sound Pressure Level) as a function of time and frequency. For the frequency scale one does, in most cases, not use the linear Hz scale but the non-linear Bark scale. This Bark scale is a pitch scale representing the... 

The frequency scale /(in Hz) is transformed to a pitch scale z (in Bark) and the signal is filtered with the transfer function a(i (z) from outer to inner ear (free or diffuse field). This results in the power-time-pitch representations px (t, z) and py(l, z) measured in (dB, seconds, Bark). A more detailed description of this transformation is given in Appendix A of [Beerends and Stemerdink, 1992]. 

The power-time-pitch representations px(t, z) and py(t, z) are multiplied with a frequency-dependent fraction e TjIx< > using Eq. (1.3) and Fig. 1.6, for addition with a time within the next frame (7/ = time shift between two frames 20 ms). This models the time-domain smearing of x(i) and y(t). 

The power-time-pitch representations px (t, z) and py(t, z) are convolved with the frequency-smearing function A, as can be derived from Eq. (1.1), leading to excitation-time-pitch (dB exc, seconds, Bark) representations Ex (t, z) and Ey (t, z) (see Appendices B, C, D of [Beerends and Stemerdink, 1992]). The form of the frequency-smearing function depends on intensity and frequency, and the convolution is carried out in a non-linear way using Eq. (1.2) (see Appendix C of [Beerends and Stemerdink, 1992]) with parameter afreq ... 

Figure 1.7 Overview of the basic transformations which are used in the development of the PAQM (Perceptual Audio Quality Measure). The signals x(t) and y t) are windowed with a window w(t) and then transformed to the frequency domain. The power spectra as function of time and frequency, Px (t, f) and Py(t, /) are transformed to power spectra as function of time and pitch, px(t, z) and py(t, z) which are convolved with the smearing function resulting in the excitations as a function of pitch Ex (/, z) ar 6Ey(t, z). After transformation with the compression function we get the internal representations x(f, z)and ,(, z) from which the average noise disturbance Cn over the audio fragment can be calculated.

Consider a fixed-frequency sinusoidal component (/) = sin(wojt + 00 ) from a musical signal, distorted by a pitch variation function p,v(t). The pitch-distorted component x,(t) can be written as (see [Godsill, 1993]) ... 

The second stage of processing involves extracting smooth pitch variation information from the time-frequency tracks. For the th block of data there will be Pn frequency estimates corresponding to the P tonal components which were being... 

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