Frequency

“ If we should gradually increase the frequency of the alternating current you would find that about sixty or perhaps a hundred cycles a second would give you the impression of a musical note. As the frequency is made still larger you have merely the impression of a higher-pitched note until we get up into the thousands of cycles a second. ”

“ As these “secondary waves” return to S their distance apart is nearly equal to twice the distance between the rails, and the observer then hears a note of wave-length nearly 2EF. But if an observer is stationed at S' the waves will be about half as far apart and will reach him with nearly twice the frequency, so that he hears a note about an octave higher. As he travels further round the frequency increases still more. The railings in fact do for sound what a diffraction grating does for light.
Frequency and Pitch. ”

“ You know that heat and light are but vibrations of the ether of various frequencies, just as are radio-active or chemical rays, and the electro-magnetic waves we use for speech and signaling. Highest of all in frequency are those electro-magnetic waves ”

“ OSCILLATIONS, ELECTRIC.--A current of high frequency that surges through an open or a closed circuit. (1) Electric oscillations may be set up by a spark gap, electric arc or a vacuum tube, when they have not only a high frequency but a high potential, or voltage. (2) When electric waves impinge on an aerial wire they are transformed into electric oscillations of a frequency equal to those which emitted the waves, but since a very small amount of energy is received their potential or voltage is likewise very small. ”

“ By “frequency” we mean the number of cycles each second. The electric current which we use in lighting our house goes through sixty cycles a second. That means the current reverses its direction 120 times a second.
In radio we use alternating currents which have very high frequencies. In ship sets the frequency is either 500,000 or 1,000,000 cycles per second. Amateur transmitting sets usually have oscillators which run at well over a million cycles per second. The longer range stations use lower frequencies. ”

“ Motion of the source alone crowds the waves together on the advancing side and spreads them out on the receding side. An observer therefore whom the source is approaching receives shorter waves, and one from whom the source is receding receives longer waves, than normal. At any fixed point waves will arrive, therefore, with modified frequency. ”

“ Analytical Power of the Ear.—When we listen to a compound tone, we have the power of picking out these partials from the general mass of sound. It is known that the frequencies of the partials as compared with that of the fundamental tone are simple multiples of the frequency of the fundamental, and also that physically the waves of the partials so blend with each other as to produce waves of very complicated forms. ”

“ APPENDIX TO THE FREQUENCY TABLES General Rules
1. Any word combination which is to be found in the frequency tables, but only in the reverse order from that in which it occurs in a test record under consideration, is to be classed as a normal reaction.
2. Any reaction word which is a synonym or an antonym of the corresponding stimulus word is to be classed as normal. ”

“ So long as a source is stationary the wave-lengths emitted are quite normal, but motion of an observer may change the frequency with which they are received, in an obvious way; they are swept up faster if the receiver is approaching, they have a stern chase if it is receding. ”

“ The distance to which messages may be transmitted and received depends on the amount of electric energy employed, the frequency of oscillation in the radiating system, the length of the electric waves emitted, the height of the perpendicular wires from the ground, the medium through which the waves are propagated, the sensitiveness of the coherer or receiver, and the precision with which the instruments are adjusted. ”

“ High-Frequency Currents.--High frequency currents, or electric oscillations as they are called, are currents of electricity that surge to and fro in a circuit a million times, more or less, per second. Currents of such high frequencies will oscillate, that is, surge to and fro, in an open circuit, such as an aerial wire system, as well as in a closed circuit. ”

“ When light is analysed by a prism or grating into a spectrum, the course of each ray is deflected—refracted or diffracted—by an amount corresponding to its frequency of vibration or wave-length.
Motion of the medium, so long as it is steady, affects neither frequency nor wave-length, and accordingly is without influence on the result. ”

“ As a disciple of Maxwell, et al, I am hopelessly incapable of concocting a workable theory of radiation which has nothing to do with some basic concept of frequency. Frequency, when you sit down and start analyzing it, is a nice, stable idea that explains a hell of a lot, Dusty, and as you get into atomics you find that particle radiation can be mathematically reduced to terms of frequency. ”

“ I have found out that by uttering the true inner name of anything I can set in motion harmonics--harmonics, note well, half the wave length and twice the frequency!--that are delicate and swift enough to insert themselves between the whirling molecules of any reasonable object--any object, I mean, not too closely or coherently packed. By then swelling or lowering my voice I can alter the scale, size or shape of that object almost indefinitely, its parts nevertheless retaining their normal relative proportions. ”

“ When such movements of certain frequency and amplitude strike our organs of vision, the sensation of light is produced. When others of greater amplitude and smaller frequency45 strike the terminal outspread of our common sensory nerves, the sensation of heat results. The difference between the frequency and amplitude of the heat waves and the light waves is but small, or, strictly speaking, there is no actual line of separation lying between them; they run directly into each other. ”

“ The fact that it is possible for a number of people to perceive the same noise or the same coloured pattern obviously depends upon the fact that a physical process can travel outward from a centre and retain certain of its characteristics unchanged, or very little changed. The most notable of such characteristics is frequency in a wave-motion. That, no doubt, affords a biological reason for the fact that our most delicate senses, sight and hearing, are sensitive to frequencies, which determine colour in what we see and pitch in what we hear. ”

“ You will thus see that while our acquaintance with wave motion below the red extends down to one-quarter of the slowest rate which affects the eye, our knowledge of vibrations at the other end of the scale only comprehends those having twice the frequency of violet light. In round numbers, we have four octaves of light, corresponding to four octaves of sound in music. In music the octave has a range to a note of double frequency. In light we have one octave of visible light, one octave above the visible range, and two octaves below the visible range. ”

“ Motion of either source or receiver can alter frequency; motion of receiver can alter apparent direction; motion of the medium can do neither.
But the question must be asked, can it not hurry a wave so as to make it arrive out of phase with another wave arriving by a different path, and thus produce or modify interference effects? ”

“ The critical frequency of a layer depends upon the layer’s density. If a wave passes through a particular layer, it may still be refracted by a higher layer if its frequency is lower than the higher layer's critical frequency. ”

“ In bringing a circuit to a state of resonance by increasing the frequency, the current will increase with increasing frequency until the critical frequency is reached, and then the current will decrease in value for further increase of frequency. ”

“ Incidentally we gain, by the use of very high frequencies, many advantages, such as a higher economy in the light production, the possibility of working with one lead, the possibility of doing away with the leading-in wire, etc. The question is, how far can we go with frequencies? Ordinary conductors rapidly lose the facility of transmitting electric impulses when the frequency is greatly increased. Assume the means for the production of impulses of very great frequency brought to the utmost perfection, every one will naturally ask how to transmit them when the necessity arises. ”

“ The problem then is this:—take some one of the well-marked patterns, such as it appears on a particular digit,—say a loop on the right thumb; find the average number of ridges that cross a specified portion of it; then this average value will determine an ideal centre from which individual [Pg 199] departures may be measured; next, tabulate the frequency of the departures that attain to each of many successive specified distances from that ideal centre; then see whether their diminishing frequency as the distances increase, is or is not in accordance with the law of frequency of error. ”

“ The higher the frequency, the more pronounced is this effect, hence the discharges select different paths through gaps and resistances depending upon the frequency. By frequency is meant, not the frequency of the line current but the lightning frequency, which may run into hundreds of thousands, or into millions of cycles. ”

“ As far as I know, the image may be composed of two sine waves of similar, but not quite identical, frequency added together. Maybe I just don't know what you mean by "spread". There can be media in which lower-frequency waves propagate faster than higher-frequency waves, so is this figure caption asserting something about light (that lower-frequency light travels more slowly? or what?) or is it asserting something that's true of all waves with a mathematical form similar to what's shown? I've changed the wording in the earlier part of the figure caption. ”

“ I list below a number of questions which must be answered in our design of delay lines. In order to fix ideas I have added the most probable answers in brackets after each question.
(1) What liquid should be used in the line? (Either mercury or a water-alcohol mixture.)
(2) Should we use a carrier? If so, of what frequency? (Yes, certainly use a carrier. Frequency should be about 10 Mc/s with water-alcohol mixture, but may be higher if desired when mercury is used) .
(3) What should be the clock-pulse frequency? (1 Mc/s) . ”

“ When the pulse recurrence frequency is as high as a megacycle we shall have to be more careful about the design, but we need not fear any real difficulties of principle about working at these frequencies, and with such band widths. The successful working of television equipment gives us every encouragement in this respect. ”

“ When a coil is operated with currents of very high frequency, beautiful brush effects may be produced, even if the coil be of comparatively small dimensions. The experimenter may vary them in many ways, and, if it were nothing else, they afford a pleasing sight. ”

“ By amendments to his specifications made April 8, 1902, he recommended that the frequency impressed upon the vertical conductor at the transmitter 'may or may not be the same as the natural period or fundamental of such conductor' and that the antenna circuit at the transmitter 'may with advantage be so constructed as to be highly resonant to a particular frequency and the harmonic vibrations impressed thereon may with advantage be of that frequency'. ”

“ At the red end of the spectrum the light in the neighborhood of that black line A has for its wave length 7.6; B has 6.87; D has 5.89; the "frequency" for A is 3.9 times 100 million million; the frequency of D light is 5.1 times 100 million million per second.
Now, what force is concerned in those vibrations as compared with sound at the rate of 400 vibrations per second? Suppose for a moment the same matter was to move to and fro through the same range but 400 million million times per second. The force required is as the square of the number expressing the frequency. ”

“ The velocity of the wave is independent of its length, being solely conditioned by the rate of vibration of the particles composing the conveying medium: while one individual particle performs one complete vibration, the wave advances one wave-length.10 The rate of particle vibration or frequency is therefore inversely proportional to the corresponding wave-length.11 Sound-waves generated by the same exciting current travel with the same velocity whatever their length, the difference being the frequency number and therefore the pitch of the note. ”

“ If n stands for the natural frequency of each circuit, where n = p/2π the above equations show that when the two circuits are coupled together, oscillations set up in one circuit create oscillations of two frequencies in the secondary circuit. ”

“ If we picture these influences as vibrations, then we may say that a certain group of vibrations of a very rapid frequency are selected by the eye and give rise to vision, that another group of very much lower frequency are selected by the ear and {65} give the sensation of sound, and other groups are selected by taste, smell, and touch. ”

“ Re-enforcement or prolongation any wave motion, such as sound, radio waves etc., resulting when the natural frequency of a body or system in vibration is equal to that of an impressed vibration.
resonant frequency. Any frequency at which a body or system vibrates most readily. The lowest resonant frequency is the natural frequency of the body or system.
responsor, n. A unit which receives the response emitted by a transponder.
restricted area. 1. An area (land, sea, or air) in which there are special restrictive measures employed to prevent or minimize interference between friendly forces. 2. ”

“ The amount of energy which may thus be passed into the body of a person depends on the frequency and potential of the currents, and by making both of these very great, a vast amount of energy may be passed into the body without causing any discomfort, except perhaps, in the arm, which is traversed by a true conduction current. ”