WO1987004311A1 - Procede de communication de donnees par radio et dispositif pour la mise en oeuvre du procede - Google Patents

Procede de communication de donnees par radio et dispositif pour la mise en oeuvre du procede Download PDF

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Publication number
WO1987004311A1
WO1987004311A1 PCT/SE1986/000591 SE8600591W WO8704311A1 WO 1987004311 A1 WO1987004311 A1 WO 1987004311A1 SE 8600591 W SE8600591 W SE 8600591W WO 8704311 A1 WO8704311 A1 WO 8704311A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
receiver
dcd
transmitter
level
Prior art date
Application number
PCT/SE1986/000591
Other languages
English (en)
Inventor
Sievert Berndtsson
Original Assignee
Atlet Ab
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 Atlet Ab filed Critical Atlet Ab
Publication of WO1987004311A1 publication Critical patent/WO1987004311A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/14—Two-way operation using the same type of signal, i.e. duplex
    • H04L5/16—Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission
    • 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

Definitions

  • the present invention relates to a method of data communication by radio, for which purpose use is made of a standardized series 5 interface which, amongst other things, handles standardized TD (Transmitted Data), RD (Received Data), DCD (Data Carrier Detect) and RTS (Request To Send) signals, a transmitter, a receiver and a common antenna with a change—over switch.
  • the invention also relates to an arrangement for the execution of the method in
  • a standardized series interface which at its contact pins handles, amongst other things, standardized TD, RD, DCD and RTS signals, together with a transmitter and a receiver connected via an antenna change-over switch to a common antenna.
  • a modem of conventional and standardized design has a band width of 3.5 kHz, which is attributable to the fact that this is the band width which was selected in order to achieve satisfactory audibility from telephone communication in return for a 5 reasonable technical and financial input.
  • the standard frequencies used for the binary characters *zero' and 'one' are 2100 Hz and 1700 Hz respectively. What this means, in conjunction with the.specified available band width, is that a conventional modem can permit a maximum of 1500 baud, which is a familiar fact 10 to experts. At these particular frequencies, this means that at least two periods are required in order to detect a character.
  • a conventional modem has a number of in—built delays, so-called 'hand—shaking* routines, which are included in order to 15* increase the reliability of the transmission.
  • These delays amount to 20-40 s, which is a comparatively long time for a 10-bit character, which is 2 ms at a rate of transmission of 4800 bits/s.
  • the object of the present invention is to make available a method
  • An arrangement which operates by the method specified in the invention is characterized in that the TD pin of the interface is connected via a voltage/frequency converter directly to the crystal oscillator of the transmitter, in that the MF signal output of the receiver is connected via a carrier wave and level detector to the DCD pin of the interface, and in that the LF signal output of the receiver is connected to the RD pin of the interface .via a level detector and a filter, so arranged as to produce a reliable RD signal on the basis of the RTS and DCD signals.
  • the designation 1 is used in the drawing to indicate a standardized series interface which, at its contact pins 2, 3, 4, 5, handles, amongst other things, the above-mentioned signals.
  • the designations 6 and 7 are used to indicate a transmitter and a receiver which are connected via an antenna change-over switch 8 to a common antenna 9.
  • a frame 10 in the form of a broken line is used to indicate the characteristic features of the invention.
  • the TD pin 2 of the interface 1 is connected via a voltage/frequency converter 11 to the crystal oscillator of the transmitter 6, which is thus modulated directly with a voltage/frequency—converted TD signal.
  • the MF signal output 12 of the receiver 7 is connected to the DCD pin 5 - .
  • the DCD signal of the interface 1 is obtained after the detection of the carrier wave and the level of the MF signal of the receiver 7.
  • the 5 LF signal output 15 of the receiver 7 is connected via a level detector 16 and a filter 17 to the RD pin 3 of the interface 1. In this way the RD signal of the series interface 1 is obtained after the level of the LF signal of the receiver 7 has been detected and filtered depending on the DCD signal obtained in
  • a sampling circuit 18 is connected to the LF signal output 15 of the receiver 7, which sampling circuit is so arranged as to monitor a d.c. voltage level in the LF signal by means of which the reference leveL of the level detector 16 is regulated.
  • the antenna change—over switch 8 is connected to the RTS pin A of the series interface 1, that is to say it is controlled by the RTS signal.
  • a data signal which is to be transmitted is fed via the TD pin 2 to the series interface 1. After voltage/frequency conversion in the converter 11, it is able to influence the crystal oscillator of the transmitter 6
  • the RTS signal which is a so-called *hand-shaking' signal at the pin A of the series interface 1, actuates the antenna change-over switch 8 so that the transmitter 6 is connected to the antenna 9.
  • the aforementioned signal also actuates the filter 17 so that any signals from the receiver 7
  • the MF signal of the receiver 7 is taken out after the second IF filter of the receiver 7, is detected in the carrier wave detector 13, and has its LeveL detected after amplification and half-wave rectification in the detector 1A, which is preferably of the comparator type, when it constitutes the DCD signal of the receiver at the contact pin 5 of the series interface.
  • the future RD signal is taken out in the form of an LF signal from the receiver 7 after the AF amplifier of the FM detector, and is sampled continuously in the sampling circuit 18, the d.c. voltage value of which is able to influence the reference level of the level detector 16, the output signal of which, after filtering in the filter 17, constitutes the aforementioned RD signal.
  • the RTS and DCD signals are used for controlling the filter 17.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Circuits Of Receivers In General (AREA)

Abstract

Procédé et dispositif pour la communication de données par radio, dans lequel on utilise une interface sérielle normalisée (1) qui traite, entre autres, des signaux normalisés DT (Données Transmises), DR (Données Reçues), DPD (Détection de Porteurs de Donnéesf et DDE (Demande d'Envoi), un émetteur (6), un récepteur (7) et une antenne commune (9) avec un commutateur (8). L'oscillateur à cristal de l'émetteur est directement modulé au moyen du signal DT de l'interface sérielle après transformation de tension/fréquence. L'onde porteuse et le niveau du signal FM du récepteur (7) sont détectés pour obtenir le signal DPD de l'interface sérielle (1). On détecte le niveau du signal BF du récepteur (7) et le filtre en fonction du signal DPD reçu et de son propre signal DDE pour obtenir le signal DR de l'interface sérielle (1).
PCT/SE1986/000591 1986-01-03 1986-12-30 Procede de communication de donnees par radio et dispositif pour la mise en oeuvre du procede WO1987004311A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8600030A SE8600030L (sv) 1986-01-03 1986-01-03 Sett vid datakommunikation med radio
SE8600030-4 1986-01-03

Publications (1)

Publication Number Publication Date
WO1987004311A1 true WO1987004311A1 (fr) 1987-07-16

Family

ID=20363011

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1986/000591 WO1987004311A1 (fr) 1986-01-03 1986-12-30 Procede de communication de donnees par radio et dispositif pour la mise en oeuvre du procede

Country Status (4)

Country Link
EP (1) EP0281566A1 (fr)
AU (1) AU6846087A (fr)
SE (1) SE8600030L (fr)
WO (1) WO1987004311A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1930046A (en) * 1929-11-12 1933-10-10 Jr John Hays Hammond System for the transmission and reception of radiant energy
DE952989C (de) * 1953-05-18 1956-11-22 Philips Nv Sender fuer Frequenzverschiebungstelegraphie
SE428513B (sv) * 1976-07-28 1983-07-04 Australasian Training Aids Pty Sett att koda och derefter avkoda en datasignal jemte anordning for kodning av en datasignal och anordning for avkodning av en datasignal

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1930046A (en) * 1929-11-12 1933-10-10 Jr John Hays Hammond System for the transmission and reception of radiant energy
DE952989C (de) * 1953-05-18 1956-11-22 Philips Nv Sender fuer Frequenzverschiebungstelegraphie
SE428513B (sv) * 1976-07-28 1983-07-04 Australasian Training Aids Pty Sett att koda och derefter avkoda en datasignal jemte anordning for kodning av en datasignal och anordning for avkodning av en datasignal

Also Published As

Publication number Publication date
SE8600030L (sv) 1987-07-04
AU6846087A (en) 1987-07-28
EP0281566A1 (fr) 1988-09-14
SE8600030D0 (sv) 1986-01-03

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