US2257917A - Multiple telegraphy and telephony - Google Patents

Multiple telegraphy and telephony Download PDF

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Publication number
US2257917A
US2257917A US207921A US20792138A US2257917A US 2257917 A US2257917 A US 2257917A US 207921 A US207921 A US 207921A US 20792138 A US20792138 A US 20792138A US 2257917 A US2257917 A US 2257917A
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United States
Prior art keywords
frequencies
telephony
transmitters
transmitter
high frequency
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Expired - Lifetime
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US207921A
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English (en)
Inventor
Pungs Leo
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Individual
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Individual
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Publication of US2257917A publication Critical patent/US2257917A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems

Definitions

  • a high frequency channel intended for telegraphy and telephony, may be utilized in multfold fashion by using multiple modulation effected with the aid of intermediate frequencies.
  • Thisy method however, for each channel merely a part-utilization of the transmitter is possible, since the total of al1 proportions should not exceed the full utilization of the transmitter.
  • special precautions are necessary in order to avoid cross modulation.
  • connection not a high frequency channel ln a narrower sense is meant here but this expression is intended to cover the transmitting and receiving system, comprising dipoles and collecting and directing means, such as reflectors, etc. Therefore the arrangement described hereafter is of special advantage when employed with connections utilizing ultra-short waves and waves in the decimetre range.
  • novel method will be advantageous wherever the cost of the said collecting and directing means is high as compared with that of the transmitter proper.
  • the transmitter is proposed to subdivide the transmitter as distinguished from the radiating system in two or more parttransmitters, thus avoiding multiple channel modulation in a single transmitter.
  • Each such part-transmitter is only modulated with an intermediate frequency and the voice frequency.
  • All of the transmitters are arranged to act simultaneously upon a radiating and collecting and directing system common to them, whilst their frequencies are so close together that on the one hand the best possible radiation conditions shall be established while on the other hand the transmitters shall not be disturbed by the high frequency side bands.
  • the attenuation of the radiation system being considerable, pretty great frequency differences of the transmitters will be admissible in general. If greater differences are admitted then in most cases there will be no necessity for neutralizing the systems. If, however, such neutralization prove to be necessary then it may be obtained with the aid of well known means.
  • the frequencies serving as intermediate frequencies should not be too high.
  • the high frequency mixture On the receiving side the high frequency mixture is received by a single collecting and directing system and is rectified and the several channels are separated with the aid of the respective intermediate frequencies. If it is desired to work with sharp feed-back connection the two carrier waves must of course be somewhat closely spaced together. Also, there is another possibility, namely, to use transmitters tuned to the fundamental waves and at the same time to use transmitters tuned to harmonics thereof. In most cases however a system of this kind will not be practicable for reasons that reside in the bundling arrangement.
  • FIGs. 1 and 1A are wiring diagrams of a transmitter and receiver, respectively showing one embodiment of the invention
  • Figs. 2 and 2A are schematic representations of a transmitting and receiver antenna, respectively, for use in arrangements of the kind shown in Fig. l.
  • Two short wave transmitters UI, U2 are adjusted to operate with approximately the same frequencies and are modulated by long wave transmitters HI, H2 which in their turn are modulated by voice frequency sources Ml, M2.
  • the receiving dipole E is connected to a device Gu that serves to rectify the short waves arriving from UI, U2.
  • the separation of the message channels is made by long wave receiving systems LI, L2 from which the Voice frequencies are taken in well known manner after a second rectification has been effected.
  • the modification shown in Figs. 2 and 2A comprises two dipoles D on the transmitting side, which are disposed in the focus of a reector S and are arranged at right angles with respect to each other while forming angles of 45 with the vertical.
  • the dipoles D are of the same dimensions and are each connected to a transmitter modulated with a respective intermediate frequency,'as described with reference to Fig. l.
  • the transmitters are approximately tuned to the same wavelength.
  • the receiving side has one dipole E, and the transmitted energy is separated here by means of the respective intermediate frequencies.
  • a system for simultaneous telegraphy and telephony comprising a plurality of separate transmitters operating at different related carrier frequencies, each of said transmitters including an intermediate stage which is modulated by signals of lower frequency and a high frequency stage modulated by energy from the intermediate stage, and a common directive radiation system including at least two antenna units, said units being tuned to a frequency related to said carrier frequencies and being adjusted for directive transmission of both said frequencies, whereby eilicient directive transmission of both signals is achieved.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Aerials With Secondary Devices (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Mobile Radio Communication Systems (AREA)
US207921A 1937-05-11 1938-05-14 Multiple telegraphy and telephony Expired - Lifetime US2257917A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE205377X 1937-05-11

Publications (1)

Publication Number Publication Date
US2257917A true US2257917A (en) 1941-10-07

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ID=5786896

Family Applications (1)

Application Number Title Priority Date Filing Date
US207921A Expired - Lifetime US2257917A (en) 1937-05-11 1938-05-14 Multiple telegraphy and telephony

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US (1) US2257917A (de)
CH (1) CH205377A (de)
FR (1) FR837756A (de)
GB (1) GB501106A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2458124A (en) * 1944-11-14 1949-01-04 Raymond M Wilmotte Synchronous frequency broadcasting

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2458124A (en) * 1944-11-14 1949-01-04 Raymond M Wilmotte Synchronous frequency broadcasting

Also Published As

Publication number Publication date
GB501106A (en) 1939-02-21
CH205377A (de) 1939-06-15
FR837756A (fr) 1939-02-20

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