US1942580A - Wireless transmission of telegraph impulses - Google Patents

Wireless transmission of telegraph impulses Download PDF

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Publication number
US1942580A
US1942580A US446326A US44632630A US1942580A US 1942580 A US1942580 A US 1942580A US 446326 A US446326 A US 446326A US 44632630 A US44632630 A US 44632630A US 1942580 A US1942580 A US 1942580A
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US
United States
Prior art keywords
telegraph
frequencies
wireless transmission
amplifier
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US446326A
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English (en)
Inventor
Thierbach Dietwald
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens and Halske AG
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Application granted granted Critical
Publication of US1942580A publication Critical patent/US1942580A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/005—Control of transmission; Equalising

Definitions

  • a reduction of the influence of the disturbing voltages can be obtained in transmitting the telegraph signals as double-current signals on two carrier waves or on one carrier wave with two modulation frequencies and in applying them at the receiving station to a compensation (differential) circuit.
  • one of the frequencies produces a positive current at the receiving station and the other a negative current.
  • Both currents may be sent, for instance through a differential relay which is not operated as soon as a positive and a negative current occur at the same time. It results therefrom that disturbances existing on both waves do not give rise to false signals. The elimination of disturbances will be the more complete the nearer the two telegraph frequencies are lying together.
  • Such a telegraph system furthermore offers the advantage that it permits of carrying out a simple fading regulation. Since a double-current signal at the receiving station always involves the existence of a signal current, the amplitude of these signals may be taken as a measure of the attenuation inherent in the transmission path. This condition can be utilized for the purposes of an automatic attenuation regulation, which fact is of further advantage in the case of simultaneous telegraphy and telephony.
  • the special control frequency usually employed for fading regulation can then be dispensed with, if the telegraph frequency is used for this end.
  • Figures 1 and 2 illustrate a constructional example of the invention, Fig. 1 representing the transmitting station and Fig. 2 the receiving station.
  • the two generators G1 and G2 which produce the adjacent frequencies f1 and f2 are, through the key relay RT, alternately applied to the transmitter S which emits a carrier frequency.
  • the band-pass filters K1 and K2 confine the telegraph spectrum in such a manner, that frequencies interfering with the telephone set, consisting of the transmitter M and the input amplifier W, are screened out.
  • the frequencies emitted in this way are received by means of a receiver E, which is followed by a control amplifier RV common to telegraphy and telephony.
  • the incoming current passing through the control amplifier is branched off to the filters K3 and K6.
  • the filter K3 rejects the speech frequencies and enables the telegraph frequencies to reach another current branching tap, in the two branches-of which are inserted filters K4 and K5 each letting through one of the two telegraph frequencies.
  • the telegraph frequencies separated in such a manner from one another are rectified by means of de- 35..-
  • the filter K6 which is so designed as to enable the telegraph frequencies to be rejected and the speech frequencies to be transmitted, permits of carrying the speech currents on to the receiving set H.
  • the control amplifier RV common to the telegraph-and speech frequencies, is used simultaneously, for fading regulation on transmitting speech, since it is controlled by means of the permanently existing telegraph frequency signals.
  • Means for receiving signals composed of double current impulses at different frequencies and continuous voice modulated oscillations including,
  • rectifiers and a rectifier having its input termi- I nals connected to the output of said amplifier and its output terminals connected to the volume control means in said amplifier.
  • Means for receiving signals composed of double current impulses of different frequencies comprising, signal absorbing means tuned to a band of frequencies, an amplifier connected with said absorbing means, said amplifier including automatic volume control means, a filter circuit signal responsive means, said amplifier including volume control means, a plurality of filter circuits connected with said amplifier, an indicator connected with one of said filter circuits, a rectifier connected with the output of another of said filter circuits, means connecting said volume control means with the output of said rectifier, a plurality of filter circuits connected with said last named filter, rectifying means connected with each of said last named filter circuits, and a difierential recording means connected with said last named rectifiers.
  • DIETWALD TI-IIERBACH DIETWALD TI-IIERBACH.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Relay Systems (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
US446326A 1929-04-25 1930-04-22 Wireless transmission of telegraph impulses Expired - Lifetime US1942580A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE352590X 1929-04-25

Publications (1)

Publication Number Publication Date
US1942580A true US1942580A (en) 1934-01-09

Family

ID=6276253

Family Applications (1)

Application Number Title Priority Date Filing Date
US446326A Expired - Lifetime US1942580A (en) 1929-04-25 1930-04-22 Wireless transmission of telegraph impulses

Country Status (3)

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US (1) US1942580A (xx)
GB (1) GB352590A (xx)
NL (1) NL31478C (xx)

Also Published As

Publication number Publication date
NL31478C (xx)
GB352590A (en) 1931-07-16

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