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WO1996002995A2 - Transmission de donnees par changement de frequence - Google Patents

Transmission de donnees par changement de frequence Download PDF

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Publication number
WO1996002995A2
WO1996002995A2 PCT/DE1995/000842 DE9500842W WO9602995A2 WO 1996002995 A2 WO1996002995 A2 WO 1996002995A2 DE 9500842 W DE9500842 W DE 9500842W WO 9602995 A2 WO9602995 A2 WO 9602995A2
Authority
WO
WIPO (PCT)
Prior art keywords
data
transmission
participants
transmission signal
carrier frequency
Prior art date
Application number
PCT/DE1995/000842
Other languages
German (de)
English (en)
Other versions
WO1996002995A3 (fr
Inventor
Hilmar Locher
Rudi Schneider
Original Assignee
Siemens Aktiengesellschaft
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 Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO1996002995A2 publication Critical patent/WO1996002995A2/fr
Publication of WO1996002995A3 publication Critical patent/WO1996002995A3/fr

Links

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
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/114—Indoor or close-range type systems
    • H04B10/1149—Arrangements for indoor wireless networking of information

Definitions

  • the invention relates to a method for the transmission of data between a plurality of subscribers, in which the data is modulated by frequency shift keying to generate a transmission signal, and to a suitable arrangement.
  • Frequency shift keying is also generally known under the term frequency shift keying (FSK).
  • FSK frequency shift keying
  • a voltage-controlled oscillator can be used, on the voltage input of which a data signal is carried. If the data signal has two discrete voltage levels, an alternating signal with two carrier frequencies is generated as the transmission signal, which, however, do not suddenly change into one another.
  • modulating and demodulating digital data difficulties can arise due to transients if the carrier frequencies are not many times higher than the data rate. By selecting the carrier frequencies at a sufficient distance from the data rate, the transmission capacity in narrow-band transmission channels is thus subject to narrow limits.
  • the object of the invention is to find a method for transmitting data in which an increase in the data rate up to the order of magnitude of the carrier frequencies is possible, and to provide a suitable arrangement.
  • the new method of the type mentioned at the outset has the features of claim 1.
  • Advantageous further developments of the method are specified in claims 2 to 9.
  • a new arrangement to carry out the The method is described in claim 10, an advantageous embodiment of this arrangement in claim 11.
  • the invention has the advantage that the carrier frequencies and the data rate can be of the same order of magnitude. Since the central subscriber also sends a carrier frequency signal to the other subscribers during the message breaks, a reference signal is constantly available to all subscribers for synchronizing their own oscillator via a phase locked loop. A synchronization character preceding the message, a so-called preamble, which would otherwise be required to synchronize the participants, is not required. Since the scanning frequency of the receivers is constantly locked onto the carrier frequency, errors in the demodulator are avoided and correct data are determined immediately from the start of a message. This is particularly advantageous if several participants communicate with a central participant via a wireless transmission medium or with a bus via a repeater.
  • inexpensive means of transmission can be used to achieve the data rate prevailing in the bus.
  • inexpensive infrared light-emitting diodes which can be operated at a maximum of 10 MHz, are sufficient for the optical transmission of data at a data rate of 1 MB / s.
  • Figure 1 shows an arrangement for the transmission of
  • FIG. 2 a block diagram of the devices of two subscribers required for the transmission.
  • the arrangement in FIG. 1 consists of a central subscriber 1, which is connected to a bus network 2 as a repeater is, as well as three further participants 3, 4 and 5.
  • the transmission takes place optically by infrared light.
  • participants 1, 3, 4 and 5 are each provided with transmission devices 6, 7, 8, 9, which have inexpensive infrared light-emitting diodes, and with receiving devices 10, 11, 12, 13 with photodiodes.
  • the transmitters 6 ... 9 are modulated via two different carrier frequency pairs in order to avoid mutual interference and to ensure a clear selection by means of bandpasses in the receiving devices 10 ... 13.
  • a first signal direction is shown in FIG. 1 by arrows 14, 15 and 16, a second signal direction by arrows 17, 18 and 19.
  • the center or repeater 1 continuously sends a signal of a frequency of the carrier frequency pair f ⁇ 0 , f ⁇ _ u to the further participants 3, 4 and 5.
  • participants 3, 4 and 5 the synchronization takes place via a phase locked loop with a voltage controlled oscillator.
  • the result is a simplex transmission with a data rate that is in the range of the carrier frequency.
  • the other participants 3, 4 and 5 send one after the other in time when they are requested to submit a message by the participant 1. They all use the carrier frequencies f2 0 and f2u »which are only switched through with a transmission enable to the transmission devices 7, 8 and 9 to generate a transmission signal.
  • the reception and the synchronous demodulation of the carrier frequencies f2 0 and d f2 U is thus possible without additional synchronization at the start of transmission, since a rigid coupling with respect to the carrier frequencies is already achieved by the direction of the arrows 14, 15 and 16 transmitted transmission signal exists. If the subscribers 3, 4 and 5 are located at a variable location, only phase-related phase shifts can occur, but these do not lead to sampling errors on the demodulated signal. Due to the type of data transmission between subscribers 1, 3, 4 and 5 according to the invention, in the case of a repeater as subscriber 1, it is possible to address subscribers 3, 4 and 5 on bus 2 directly as subscriber 20.
  • repeater 1 Similar to repeaters that connect two identical segments of a bus system to one another, repeater 1 also establishes a bus connection between subscribers 3, 4 and 5 and subscriber 20 located in another segment. If the data rate on bus 2 is also 1 MB / s, no special features need to be taken into account when transferring data via repeater 1. Participants 3, 4 and 5 on the wireless transmission medium can have master and slave functions, so that master-slave operation and multimaster operation as well as mixed operation are possible.
  • FIG. 2 shows the block diagram of a central participant 21 and a further participant 22.
  • a central clock 24 of 12 MHz is generated in the subscriber 21 by an oscillator 23. This central clock 24 is performed on two dividers 25 and 26.
  • a switch 27 is controlled by the data 28 to be sent, which are provided by further devices of the central subscriber 21, not shown in FIG. 2.
  • the transmission data 28 are synchronized with the central clock 24 so that the switching points of the switch 27, which Dulator of the transmission data 28 acts to always come to the times when the carrier frequency signals supplied by the dividers 25 and 26 are in phase.
  • the zero crossing of the carrier frequency signals is preferably selected as the switchover point.
  • a light-emitting diode with a suitable connection 29 generates an optical transmission signal 30 from the modulated transmission signal.
  • the further subscriber 22 has a photodiode with a signal amplifier 31 for receiving the optical transmission signal 30 for generating a digital reception signal 32.
  • the signal 32 is fed both to a phase locked loop and to a synchronous demodulator 33.
  • the phase-locked loop which consists of a phase comparator 34 and a voltage-controlled oscillator 35, is used to synchronize the subscriber 22 so that it is clocked at the same frequency as the central subscriber 21.
  • a clock signal 36 is generated by the phase control loop, which corresponds to the central clock 24.
  • the synchronous demodulator 33 delivers received data 37 from the digital received signal 32. Since an optical transmission signal 30 is also transmitted by the central subscriber 21 during message breaks, the clock signal 36 is always at the central clock 24 synchronized, and receive errors at the start of messages are avoided. Similar to the sending device of the central subscriber 21, the sending device of the other subscriber 22 is also constructed.
  • Synchronized with the clock signal 36, transmission data 40 for modulation and a control signal 41 for transmission release are routed to a switching device 42 in the further subscriber 22.
  • a light-emitting diode with a suitable connection 43 in turn supplies an optical transmission signal 44.
  • This is received in the central subscriber 21 by a photodiode with a signal amplifier 45 and in a synchronous demodulator 46 which is controlled by the central clock 24. clocks is converted into received data 47.
  • the internal connection of the central subscriber 21, for example for the simultaneous transmission of the received data 47 as transmitted data 28 in a repeater function, is not shown in FIG. 2 for reasons of clarity.
  • the transmission method according to the invention is also applicable to other physical transmission types, e.g. B. wired or with radio, applicable.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computing Systems (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Small-Scale Networks (AREA)

Abstract

L'invention concerne un procédé et une configuration de transmission de données entre plusieurs abonnés (1, 3, 4, 5). Les données sont modulées par changement de fréquence, ce qui permet de produire un signal de transmission (14...19). Les fréquences porteuses affectées à chaque valeur constituent des multiples entiers de la moitié du débit des données et les signaux des fréquences porteuses sont couplés asservis en phase au signal de données, de sorte que la phase des signaux des fréquences porteuses coïncide, chaque fois que les données changent de valeur. Un abonné central (1) émet, y compris pendant les pauses de transmission, pendant lesquelles aucune donnée ne doit être transmise, un signal de transmission (14, 15, 19) avec une fréquence porteuse d'une valeur de donnée, ce signal étant reçu, démodulé et utilisé à des fins de synchronisation par les autres abonnés (3, 4, 5). L'invention présente l'avantage de n'entraîner aucune perte de données au début d'un message, et de permettre l'utilisation de moyens de transmission dont la fréquence de coupure se situe dans le même ordre de grandeur que le débit des données. L'invention peut être utilisée dans la transmission des données en général.
PCT/DE1995/000842 1994-07-13 1995-06-29 Transmission de donnees par changement de frequence WO1996002995A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19944424741 DE4424741A1 (de) 1994-07-13 1994-07-13 Verfahren und Anordnung zur Übertragung von Daten
DEP4424741.9 1994-07-13

Publications (2)

Publication Number Publication Date
WO1996002995A2 true WO1996002995A2 (fr) 1996-02-01
WO1996002995A3 WO1996002995A3 (fr) 1996-04-25

Family

ID=6523065

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1995/000842 WO1996002995A2 (fr) 1994-07-13 1995-06-29 Transmission de donnees par changement de frequence

Country Status (2)

Country Link
DE (1) DE4424741A1 (fr)
WO (1) WO1996002995A2 (fr)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0147008A3 (fr) * 1983-09-30 1986-07-16 Texas Instruments Incorporated Modem digital utilisant la modulatio n à déplacement de fréquence
JPS6180932A (ja) * 1984-09-28 1986-04-24 Nec Corp Ｍｓｋ型変調方法

Also Published As

Publication number Publication date
DE4424741A1 (de) 1996-01-18
WO1996002995A3 (fr) 1996-04-25

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