At first it was usual to join the microphone transmitter in the direct circuit.
" I am a transmitter," Confucius is reported to have said.
It was found that to achieve this result the transmitter must be so constructed as to send out prolonged trains of slightly damped waves.
This receiver therefore, like the transmitter, consists of an open and a closed electric oscillation circuit inductively connected together; also the two circuits of the receiver must be syntonized or tuned both to each other and to those of the transmitter.'
variation in resistance of the transmitter spoken into causes a variation of the pressure at the line terminals of the impedance coils, and since those terminals are common to the two circuits the variable E.M.F.
- Telephone Set with Transmitter in a Local Circuit.
In the Ader transmitter as many as twelve carbon pencils were employed, arranged in a series of two groups with six pencils in parallel in each group. These were supported at their ends in parallel carbon bars, which were carried by a nearly horizontal wooden diaphragm.
His transmitter consists of a nearly closed oscillating circuit comprising a condenser or battery of Leyden jars, a spark gap, and the primary coil of an oscillation transformer consisting of one turn of thick wire wound on a wooden frame.
A telephone transmitter and a receiver on a novel plan were patented in July 1877 by Edison, shortly after the introduction of Bell's instruments.
The earliest instrument of this kind was the Hunnings transmitter, patented in 1878.
The transmitter on long and high resistance lines worked better by joining, in the manner shown in fig.
This seems to have been the first transmitter in which it was proposed to use the resistance at the contact of two conductors.
To eliminate the sluggish action of the selenium transmitter a selenium cell similar to that at the transmitting station is arranged at the receiving apparatus, and exposed to precisely similar variations of light, the arrangement being such that the lag of this cell counteracts the lag of the transmitting cell.
His proposed radiator and absorber consisted of two wing-shaped plates of copper, the transmitter plates being interrupted in the centre by a spark gap, and the receiver plates by an inductance coil from the ends of which connexions were made to a coherer.
A type of transmitter which has come to be invaluable in connexion with long distance telephony, and which has practically superseded all other forms, is the granular carbon transmitter.
He was a "transmitter, not a maker," but herein lies his greatness.
Each coil is attached to a shaft by a bell crank arrangement, and to these shafts there is secured a system of levers similar to that at the transmitter carrying the receiving pencil at the junction.
Thus, in the Crossley transmitter four hard carbon pencils were arranged in a lozenge-shaped figure, the ends of each pencil resting loosely in a small carbon block.
The sage, probably, did not think it necessary to put down many of his own thoughts in writing, for he said of himself that he was " a transmitter, and not a maker."
The apparatus for generating the electric action at one end is commonly called the transmitting apparatus or instrument, or the sending apparatus or instrument, or sometimes simply the transmitter or sender.
The messages in the form of perforated tape are then passed through an automatic transmitter, something like a Wheatstone transmitter, at a speed of about 100 words a minute.
The slips are passed through an ordinary Wheatstone transmitter and actuate Wheatstone receiving apparatus which in turn controls a " Creed receiving perforator."
In the Rowland multiple method of telegraphic working, the transmitter consists of a mechanical keyboard provided with a series of levers, which effect certain combinations of positive and negative currents for each letter.
In circuit with this battery was placed the secondary circuit of an induction coil, the primary circuit of which contained a telephone transmitter or microphone interrupter.
The receiving arrangements comprised also an open or antenna circuit connected directly with a closed condenser-inductance circuit, but in place of the spark gap in the transmitter an electrolytic receiver was inserted, having in connexion with it as indicator a voltaic cell and telephone.
It is obvious that this apparatus might be used either as a transmitter or as a receiver, but that the effects must under ordinary circumstances be in either case extremely feeble.
When the sounding board was spoken to or subjected to sound-waves, the mechanical resistance of the loose electrode, due to its weight, or the spring, or both, served to vary the pressure at the contact, and this gave to the current a form corresponding to the sound-waves, and it was therefore capable of being used as a speaking-telephone transmitter.'
The impedance coils shown connected between the battery and the lines and between the latter and the transmitters are joined up non-inductively as regards the transmitter circuits, but inductively as regards the secondary circuits.
The conditions permit of the circulation of the alternating currents of low periodicity, which are used for operating the bells, but in respect of the battery the circuit is open until the subscriber lifts the receiver, when the hook switch, thus released, joins the transmitter with one winding of an induction coil in series across the circuit.
He devised the "A, B, C" telegraph instrument, the automatic transmitter, by which messages may be sent at the rate of 500 words a minute, printing telegraph receivers of various forms, electrical chronoscopes, and many forms of electrical recording apparatus, - amongst others two sets of registering meteorological instruments, of which the earlier, described in 1842, was afterwards developed by Father A.
Several methods have been employed for making observations of the form of alternating current curves - (1) the point-by-point method, ascribed generally to Jules Joubert; (2) the stroboscopic methods, of which the wave transmitter of H.
It consists in punching, by means of " a puncher," a series of holes in a strip of paper in such a way that, when the strip is sent through another instrument, called the " transmitter," the holes cause the circuit to be closed at the proper times and for the proper proportionate intervals for the message to be correctly printed by the receiving instrument or recorder.
Owing to the difficulty of maintaining perfect balance on duplexed cables, curb sending is not now used, but the signals are transmitted by means of an apparatus similar to the Wheatstone automatic transmitter used on land lines and differing from the latter only in regard to the alphabet employed; the signals from the transmitter actuate a relay having heavy armatures which in turn transmit the signals to the cable; this arrangement gives very firm signals, a point of great importance for good working.
When the methods for effecting this had been worked out practically it finally led to the inventions of Slaby, Braun and others being united into a system called the Telefunken system, which, as regards the transmitter, consisted in forming a closed oscillation circuit comprising a condenser, spark gap and inductance which at one point was attached either directly or through a condenser to the earth or to an equivalent balancing capacity, and at some other point to a suitably tuned antenna.
In conjunction with the above receiver he employed a transmitter, which consisted of a large induction or spark coil S having its spark balls placed a few millimetres apart; one of these balls was connected to an earth FIG.
This receiving apparatus, with the exception of the Morse printer, was contained in a sheet-iron box, so as to exclude it from the action of the sparks of the neighbouring transmitter.
- Edison's Microphone Transmitter.
This alteration of charge caused a corresponding change in the mutual attraction of the plates of the condenser; hence the flexible plate was made to copy the vibrations of the diaphragm of the transmitter.
Almost simultaneously with Berliner, Edison conceived the idea of using a variable resistance transmitter.
The chief difficulty with this transmitter, and with various others of later date based upon it, has been the frequent packing of the carbon granules, which renders the instrument inoperative.
7, the microphone, a battery and the primary of an induction coil in a local circuit, and putting the line in circuit with the secondary of the induction coil, which acted as the transmitter.
The heavier cores, with the consequent advance in speed of working attainable, have necessitated the introduction of automatic sending, the instruments adopted being in general a modification of the Wheatstone transmitter adapted to the form of cable signals, while the regularity of transmission thus secured has caused its introduction even on circuits where the speed cannot exceed that of the ordinary operator's hand signalling.
We incur the added expense to protect the transmitter in a sturdy housing machined from aircraft aluminum.
The different styles available include the Emergency, which has a built-in micro transmitter that broadcasts on 121.5 MHz aircraft emergency frequency.
Each transmitter is therefore able to transmit a separate series of positive and negative currents in different combinations; these are distributed, by suitably arranged distributors and relays at the receiving end of the line, into their respective receivers.
The next transmitter of note was that introduced by Francis Blake, which came into wide use in the United States of America a.nd other countries.
- Blake's Transmitter.
The difficulty was first satisfactorily overcome in the long-distance transmitter, invented by A.
Tele2's customers are connected by radio in effect, through a small roof mounted aerial, to a local transmitter.
Transmitter Small sealed units that contain the electronic circuitry needed to produce radio signals.
transmitter circuitry to power levels generally below 10W and typically below 500mW.
Brain waves can be measured by implanting a small radio transmitter device into a rat that sends data to an external recorder.
Fitted to the aircraft is a microwave downlink transmitter.
excitatory transmitter in the central nervous system.
Connections shown in red have an excitatory effect on target structures (primarily through the transmitter glutamate ).
The transmitter loaded into the wire with just a series inductor for matching.
kilowatt transmitter from Z & I Aero Services in London.
klystrons based on TV transmitter technology.
My neighbor is a tv transmitter mast; lovely tv reception!
The remote control system, comprising the keypad, transmitter. infra-red link, amplifier and control microcomputer.
Several companies made small spark-gap transmitter unit to send Morse up to a 200 feet range for such experimenters.
mounted aerial, to a local transmitter.
A small oscilloscope was built into the transmitter to aid with alignment and set-up the operation of the PA stages.
The alert units typically have a base that sits in the house and a transmitter in the form of a bracelet or necklace.
Then it sends these digital signals to a transmitter worn behind the ear.
A magnet holds the transmitter in place through its attraction to the receiver-stimulator, a part of the device that is surgically attached beneath the skin in the skull.
The receiver picks up digital information forwarded by the transmitter and converts it into electrical impulses.
After about a month, the surgical wounds will have healed, and the child returns to the implant clinic to be fitted with the external parts of the device (the speech processor, microphone, and transmitter).
With a transmitter that can reach up to 200 nautical miles, the Breitling Emergency Mission could save your life.
In addition to its distinctive styling, the watch has a built in transmitter.
The transmitter, when activated, will alert rescue authorities in case of an accident.
With its in built micro transmitter, you can just imagine giving this to James Bond.
The built in micro transmitter broadcasts on the 121.5 MHz aircraft emergency frequency.
If a pilot is to crash land an airplane, he is able to activate the micro transmitter which will alert search and rescue.
The micro transmitter is activated by removing a cap on the watch which releases an antenna.
It is very important to note that the radio transmitter should not be set off in error.
It is essential that this advice is followed to ensure the reliable operation of the micro transmitter.
The side rows of holes only are used for transmitting the message, the centre row being required for feeding forward the paper in the transmitter.
This slip is then passed through a transmitter fitted with brush contacts and connected to the two line wires of a metallic loop. One circuit is formed by the loop itself, and a second, quite independent, by the two wires in parallel, earthed at each end.
The function of the " combiner " in each receiving instrument is so to group the received combination of positive and negative currents that they operate polarized relays in such a manner that the position of the tongues corresponds with the operation of the levers on the transmitter.
By means of this " light-relay " the intensity of the light acting at any moment upon the sensitized paper is made proportional to the illumination of the selenium in the transmitter.
By a modification of this apparatus the message, instead of being immediately re-transmitted into the second cable, can be punched on a paper slip, which can be inserted in the usual way into an automatic transmitter, so as to send either cable or Morse signals.
The microphonic portion of the transmitter is contained in a thin cylindrical box or case of brass A, the inner curved surface of which is covered with an insulating layer of paper.
- Solid Back Transmitter.
This instrument has almost entirely displaced all other forms of transmitter.
It is curious that this tradition is ascribed by al-Marzugi and his teacher Abu 'Ali al-Farisi to Abu `Ikrima of Dabba, who is represented by al-Anbari as the transmitter of the correct text from Ibn al-A`rabi.
Section contents: transmitter aerials Crystals Tips and tricks How Safe is RC Flight?
This provides the transmitter functionality, and a similar approach is taken with the receiver photodetector array.
quacking like a duck on his radio transmitter.
radiolocation transmitter loop prior to use.
routed out as a master to a pocket transmitter, or to a wired power supply unit.
The article included a complete schematic of the transmitter, which is reproduced below.
transmitter mounted on the engine inlet section.
Aspartate, also an excitatory transmitter, is present at a concentration of 1 - 3 mmol/L.
As stated before the Blaster is a powerful infrared transmitter.
transmitter mast; lovely tv reception!
transmitter coil which is worn on the side of the head.
transmitter pulse duration depends upon the duration of the output pulse from the ringing oscillator.
transmitter antennae for the " Chain Home " radar system.
I have just called Beaker using the radio transmitter to find out exactly where he is.
Their photographers use a wireless transmitter to link their camera to a laptop.
It has a range of 10m from chest transmitter to wrist unit.
- Wheatstone Automatic Transmitter.
In these annular spaces there are suspended by springs two light coils of fine copper wire, capable of being moved vertically, and connected in such a manner as to be traversed by the two variable line currents from the transmitter.
The problem of syntonic electric wave telegraphy is then to construct a transmitter and a receiver of such kind that the receiver will be affected by the waves emitted by the corresponding or syntonic transmitter, but not by waves of any other wavelength or by irregular electric impulses due to atmospheric electricity.
A vertical transmitting antenna sends out its waves equally in all directions, and these can be equally detected by a suitable syntonic or other receiver at all points on the circumference of a circle described round the transmitter.
This has been achieved by employing a microphone transmitter at the sending end to vary the amplitude but not the wave-length of the emitted waves, and at the receiving end using an electrolytic receiver, which proves to be not merely a qualitative but also a quantitative instrument, to make these variations audible on a telephone.
The apparatus thus acted as both a transmitter and a receiver; indeed it is essentially the magneto-receiver which has come into universal use in practical telephony, though for transmission it was soon superseded by forms of microphonic transmitters.
The transmitter (fig.
On the 4th of April 1877 Emile Berliner filed a caveat in the United States patent office, in which he stated that, on the principle of the variation with pressure of the resistance at the contact of two conductors, he had made an instrument which could be used as a telephone transmitter, and that, in consequence of the mutual forces between the two parts of the current on the two sides of the point of contact, the instrument was capable of acting as a receiver.
C. White in the laboratory of the American Bell Telephone Company, and commonly known as the " solid back transmitter " (fig.
The transmitter is placed in multiple with the primary winding of an induction coil whose secondary operates in the loop circuit, and consequently when the transmitter is spoken into, a variable E.M.F.
It is probable (see above) that Mahomet had already caused revelations to be written down at Mecca, and that this began from the moment when he felt certain that he was the transmitter of the actual text of a heavenly book to mankind.
An Australian man was fined $ 2,000 for quacking like a duck on his radio transmitter.
Photograph 1 Leveling a radiolocation transmitter loop prior to use.
Set top aerials gave little trouble - probably due to the proximity of the relay transmitter.
The signals can be mixed and routed out as a master to a pocket transmitter, or to a wired power supply unit.
The receiver and transmitter must be synchronized to ensure data is correctly transferred.
This is provided by an electrical transmitter mounted on the engine inlet section.
These parts are connected to a transmitter coil which is worn on the side of the head.
PUT ALL YOUR HEART INTO IT The unit is available with or without transmitter belt.
If it is used as such the transmitter pulse duration depends upon the duration of the output pulse from the ringing oscillator.
The tower was one of four similar towers at Bawdsey that supported the transmitter antennae for the " Chain Home " radar system.
This electronic dog training collar works via a transmitter and a receiver.
The receiver is attached to the dog collar, and the person training the canine operates the transmitter.
The first remote control opener had a transmitter and a receiver that controlled the opener.
Nicotine is a physiologically addictive; research has shown that it increases the levels of dopamine, a neurological transmitter, in the smoker's brain.
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