Transmitter

“ The words spoken in the transmitter cause the current to fluctuate and the induction coil raises the potential of the current sufficiently to charge the condenser and cause a slight vibration of the paper dielectric. The vibrations correspond in strength and speed to those of the voice, and so the words spoken in the transmitter are audible to the person over whose ears the paper is pressed.
Everything about the apparatus must be as dry as possible, to insure its successful operation. The people holding the wires in their hands should stand on a carpeted floor. ”

“ When used in connection with his articulating transmitter, which was developed at a later date, articulate words have been received upon it; and when a duplicate of the instrument is inserted in a closed circuit, which includes a galvanic battery, it becomes a speaking telephone capable of acting both as a transmitter and as a receiver. Mr. Gray did not know at that time, however, that he could use it as a transmitter, although he had fully demonstrated its ability to receive sounds of varying quality. ”

“ Between the transmitter and receiver, on whose necessary identity of vibrations he constantly insists, he employs an electric current as the intermediate, to take on, in its wave-motions or polarizations, all the possible variations of the sound-waves striking on the transmitter, and to give them up again to the receiver. Reis, without talking about "undulatory" currents, makes them the staple of his telephone. ”

“ It gave strong indication at one and a half meters. The wave length of their control transmitter! If only he could find—but there it was: a direction finder. Hastily, he lighted its tubes and tuned to the frequency shown by the meter. He rotated the loop over the compass dial and carefully noted maximum and minimum signals. He had a line on the transmitter! And it must be close by, for the intensity of the carrier wave was tremendous.
lipping the automatic into his pocket, he left the laboratory and struck out through the underbrush in the direction Carlos had taken the day before. ”

“ The parts of the apparatus which take up the sound waves and change them into electric currents compose the transmitter. In the form of transmitter most commonly used, the motions of the diaphragm cause variations in the strength of a current flowing from a battery by varying the resistance in the path of the electric current.
The sounds are directed to the mouthpiece, which causes the vibrations of the air to strike the diaphragm, on the back and center of which is fastened a small cup shaped piece of carbon. A second cup is mounted in a rigid position directly in back of the first. ”

“ The transmitter as a rule consists of a mechanically or motor driven mechanism which causes the telegraph impulses to be transmitted to the line, and the combination and character of the impulses are determined by the tape perforations. The rapidity with which the tape may be driven through the transmitter makes very high speed operation possible. Of course it is necessary that there should be at the other end of the wire apparatus capable of receiving and recording the signals as speedily as they are sent. ”

“ The circuits are so constructed that the electrical impulses in the antenna circuit of the transmitter vibrate longer with the application to the transmitter of a given amount of electrical energy than had been the case in the previous structures known to the art, and the selectively and sensitivity of the receiver is likewise enhanced. Thus increased efficiency in the transmission and reception of signals is obtained. ”

“ When a person speaks into the transmitter, the sound waves of the voice cause the diaphragm to vibrate, this action causes rapid changes in the resistance of the transmitter, which in turn causes the direct current to fluctuate just in step with the pulses of the voice waves. This fluctuating direct current passes through the primary of an induction coil, producing in the secondary an intensified alternating current. ”

“ There was a red mark on the input meter of the transmitter. That red line marked the critical point. If more power was put through the transmitter, it would break down the fabric of space between this dimension and the fourth dimension. ”

“ 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'. ”

“ Grant laughed. "My dear, if they're reading your mind without your will, that's not treachery. Frankly, I've studied the problem myself, and I know that such is impossible. In no known science has there ever been a situation where a transmitter can be heard without the transmitter aware of its output. By 'transmitter' I mean people talking, men holding radioactives, radio, subradio, light, sound, and fury. Furthermore, since unwitting aid is ruled out, if such aid is given, it is given willingly. And that, Jenna, I refuse to believe." ”

“ The part spoken to is called the transmitter, and the part which gives the sound out again is called the receiver. Sound itself does not pass over the line. Although the same apparatus may be used for both transmitter and receiver, they are generally different in construction.
Fig. 165. 480. The Bell or Magneto-transmitter generates its own current, and is, strictly speaking, a dynamo that is run by the voice. You have seen, by experiments, that a current can be generated in a coil of wire by moving a magnet back and forth in front of its soft iron core. ”

“ The mechanism of the transmitter is complicated and cannot be described except scientifically. Its use allows one to talk long distances, even to the extent of 2,000 miles. Non-technically speaking, then, the telephone consists of a magnet, insulated wire, and a disc, the vibration upon the disc being transmitted over the wire from the sending to the receiving station, electricity being used for conveying the vibrations or sound. ”

“ The construction of the transmitter will appear from the diagram. Between two disks of carbon is placed granular carbon. One disk is in contact with the solid back of the instrument, while the other is in contact with the diaphragm on which the sound waves impinge. The back of the transmitter forms one electrode, while the front plate is insulated from the rest of the apparatus and is connected with the other conductor. There are numerous other forms of transmitter which are constantly increasing with the extending use of the telephone for interior use and by independent companies. ”

“ The distance that can be covered with a wireless telephone transmitter is about one-fourth as great as that of a wireless telegraph transmitter having the same input of initial current, but it is long enough to satisfy the most enthusiastic amateur. ”

“ The transmitter is an all transistorized unit, containing a push-pull output stage to obtain a minimum output of 200 milliwatts at a frequency of 246.3 mc. The transmitter frequency is derived by taking the basic frequency of an oscillator and multiplying it through a series of tripler and doubler stages.
The transmitter is powered by a de-de voltage regulator. The regulator is completely transistorized and supplies a regulated output voltage of 28 vdc. To reduce the probability of obtaining a spurious output signal, a band pass filter is placed in the output circuit. ”

“ In both transmitter and receiver the currents are transformed and rendered more effective and suitable for the operation of any desired device. Properly constructed, my system is safe against static and other interference and the amount of energy which may be transmitted is billions of times greater than with the Hertzian which has none of these virtues, has never been used successfully and of which no trace can be found at present. ”

“ A telephone receiver is connected across the terminals of the detector. When the electromagnetic waves from the transmitting station strike the aerial of the receiving station, they set up therein a series of high frequency oscillations, corresponding to the Morse signals emitted from the transmitter. The oscillations flow back and forth through the aerial and ground, striking the mineral detector on their journey. The high frequency oscillations are alternating currents, because they reverse their direction many thousand times per second. ”

“ The capacity of the two instruments last described for transmitting sounds seems to depend upon the fact that the current is made to pass through an imperfect contact, which, when acted upon by the vibrations of sound, gives to the current an undulatory character. Successful experiments have been made with loose-jointed machinery used as a transmitter. Even a common nail laid loosely across two other nails, insulated from each other but connected with a battery, will make a good transmitter. ”

“ The waves which come from the transmitter, perhaps 2,000 miles away, are received on a suspended kite-wire, exactly similar to the wire used in the transmitter, but they are so weak that they could not of themselves operate an ordinary telegraph instrument. They do, however, possess strength enough to draw the little particles of silver and nickel in the coherer together in a continuous metal path. ”

“ Mr. Bell was in the habit of observing the pitch of a spring by pressing it against his ear while the corresponding transmitter in a distant room was sending its intermittent current through the magnet of that receiver. He would then manipulate the tuning screw until that spring was tuned to accord with the pitch of the whine coming from the transmitter. All this experimenting was carried on in the upper story of the Williams building, where we had a wire connecting two rooms perhaps sixty feet apart looking out on Court Street. ”

“ If a person speak into the transmitter, one at the receiver can hear what is said, even though there are no batteries in the circuit. It is a well known fact that two telephone receivers connected up in this way will transmit words between two persons, for the voice vibrating the diaphragm causes an inductive current to flow and the other receiver copies these vibrations. But in this experiment, a transmitter which induces no current is used. Do the carbon and the zinc and the moist earth form a battery? ”

“ The aerial wire is precisely the same for either wireless telegraphy or wireless telephony. The transmitter of a wireless telegraph set generally uses a spark gap for setting up the electric oscillations, while usually for wireless telephony a vacuum tube is employed for this purpose. The receptor for wireless telegraphy and telephony is the same and may include either a crystal detector or a vacuum tube detector, as will be explained presently. ”

“ Popularly speaking, it may be said that the transmitter takes the varying sounds of the human voice, and passes them on to the telephone wire, to be borne along thereon by the undulatory electric current until they reach the receiver, which takes and passes them to the human ear. ”

“ There's no way to predict when a given transmitter is going to fail in such a way that it may transmit incorrectly on frequencies other than is intended, and when we get reports from pilots or from our flight test folks of such occurrences, then we send out folks specially equipped to locate those ground stations and get them corrected. ”

“ These were supported at their ends in parallel carbon bars, which were carried by a nearly horizontal wooden diaphragm. Such multiple-electrode transmitters give a loud although somewhat harsh sound, and will bear being spoken to very strongly without breaking the circuit.
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. The earliest instrument of this kind was the Hunnings transmitter, patented in 1878. ”

“ I told him about my visitor and the repair job. "What I did was add a modulator-oscillator-power amplifier, and a few feet of wire for an antenna, coiled around inside the case."
"So what does that make it?"
"Simple. It makes it a radio transmitter. Not only will he hear what the horses are saying, but anyone in town with a radio tuned to that frequency will, too."
"And where does that get you?" The sergeant was still puzzled but not bored now. ”

“ A 50 to 100 Mile Wireless Telephone Transmitter--With Direct Current Motor Generator.--As the initial source of current available is taken to be a 110 or 220 volt direct current a motor-generator having an output of 350 volts must be used as before. The only difference between this transmitter and the preceding one is that: (1) two 5 watt tubes are used, the first serving as an oscillator and the second as a modulator; (2) an oscillation choke coil is used in the plate circuit; (3) a reactance coil or reactor, is used in the plate circuit; and (4) a reactor is used in the grid circuit. ”

“ We generate a signal, vary the frequency until I lose my mutant powers—and that's it! We generate as strong a signal as we can. Then we have every transmitter in the country put on a direct line to us. When the radar spots the first saucer, we let go with every kilowatt of power we've got. ”

“ 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. ”