DE1922641C3 - Arrangement for automatic delay equalization of telephone channels for the transmission of data - Google Patents

Description

J _6n remaining unknown function names gui eni complementary computations generated in the equalizer

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The invention relates to an arrangement for delay equalization of telecommunication channels for

tSglng of data, wherein the Obenmgd sendestiti * and empfangsseitigein Uufzeitmeßplatz _a i _tung this purpose, only the undbejetaer at an upper voice band area, based on

, needed. The be.den Laufze.tun computing circuit such that

SÄethneU becomes in increasing M ^ for the transmission of data mhbemitztJDieWaW

gen on. You have to become a CteLtant for data transfer; Uuftime equalization must 5 »must be adapted to the corresponding dial-up connection each time. For data transfer on FeSfachleitung is thus an automatic adjusting runtime equalizer to be used ^

It is known to use an equalizer for ^{asynchronous data} transmission on dedicated telephone connections, which is a chain connection

Contains all-pass terms of the 2nd order. For one-time manual adjustment of the numerous equalizer parameters an IEDV system is required which the previously measured frequency-dependent delay time

Evaluation of the corresponding telephone connection (Frequency, year 1988, issue 9, pages 267

Families of curves

55

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It is also known that in order to equalize the attenuation of submarine cables in these at certain distances To install Entzerningsneizwerke, the frequency-dependent Generate sets of evaporation curves, .With a computer system must also have the curves here

Course of the two Ku ^^^^

Re embodiment of the invention of a re g ^ _ejner

complementary curve w, rd generated by ^^ ,, paB ^ of the 2nd order. 5 | «it sfch that after the coarse equalization has been carried out _en ^ _r ? _ch end the approach described above is fm ensr ^ ngsbereich a predetermined deviation in the fc ™™ Jg is exceeded, are in, Welf ^he ^ "™" _{Η the} invention, the residual nts at 2 medium Frequenzer _e f _ner extended Rechenschaltunj | _{that one of the} selected E.nze

so poor ι . _esermitt , _erenFreqU enzenortl » _C l kurven.möe is lowered that the front

^^ Deviation of the remaining term complied with,

will

rd "," "example of the invention is in dei

™ ⁿ _dg ? _represent i _t ^F and in the following it becomes close to | _eigt

| _ma-Nazi equalization vo

Telephone lines for data transmission,

Fig. 2 decomposition of a given runtime function into 3 characteristic functions,

Fig. 3 family of curves, depending on a parameter V,

Fig. 4 set of slides, depending on a parameter μ,

Fig. S circuit of the computing circuit, Fig. 6 Mode of operation of the fine equalization.

1 gives a general overview of the function of a data transmission system with the described undistorter arrangement. Before the actual data is transmitted, a transit time measuring station is connected to the transmission channel 3 on the transmit side 1 and the receive side% , and the transit time differences 4 and 5 are measured at a lower frequency 6 and an upper frequency 7 in the speech range, based on the center frequency. The transit time differences 4 and S are the input variables of a computing circuit 8, which calculates the values of the parameters V9 and μΙΟ, which in turn control the follower controllers H and 12. The tracking controllers 11 and 12 change the frequency-dependent elements in the partial equalizers 13 and 14 so that the complementary delay curve corresponding to the value of the parameter V9 or μΙΟ is generated in the partial equalizer 13 or 14. The entire equalizer 15 also contains a partial equalizer 16 in which a fixed runtime curve is generated which has a complementary profile to that indicated in the Tefl equalizer 16.

When the setting of the curves in the partial equalizer η 13 and 14 has ended, the transit time measuring stations become switched off from the transmission channel 3 and the modems 17 and Ii and the equalizer 15 on the transmission channel 3 switched on. The data transfer can now begin.

The principle of delay equalization is explained in more detail in FIG. The transit time function 19 of the transmission channel 3 from FIG. 1 is given. This transit time function 19 in FIG. 2 can be approximated well by adding the runtime function of V-TF route sections 20, the runtime function of an interpolation polynomial 21 dependent on μ, and the fixed predetermined runtime function of the exchange 22. The delay function 19 is thus equalized by the connection in series of 3 Teilentzerrern 13, 14,16 in Fig. 1, since it Teilsntzerrer generate the complementary shape of the curves 20, 21, 22 ir. FIG. 2. Every possible single curve of the family of curves in Fig. 3 and FIG. 4, the complementary course of which is generated in the partial equalizers 13, 14 in FIG. 1, is determined by a value of the parameters V and μ each. The two values of the parameters V9 and μ lift are output variables of the computing circuit 8 in FIG. 1. In order to be able to determine them in the computing circuit 8, it requires 2 input variables. The input variables are the transit time differences 4 and 5 at a lower frequency 6 and an upper frequency 7 in the speech range,

gen to a center frequency: 23 in FIG. 2. In the computing circuit 8 according to FIG. 5, the solution of a linear system of equations with 2 unknowns V9, μ 10 is implemented. The input variables 4,5 are given as voltages via coefficient potentiometers 24, 25, 26,

ίο 27 placed on the summing amplifiers 28, 29, to which the two fixed DC voltages 30, 31 are also applied. The unique, fixed setting of the sizes from 24 to 31 depends on the underlying, characteristic course of the families of curves according to FIG. 3 and F i g. 4 and curve 22 in FIG. 2 from. For this purpose, the ordinate values of the basic curve at the lower frequency 6 and the upper frequency 7 are required. The basic curves of the families of curves in FIG. 3 and FIG. 4 are those that are defined by the parameter values V = 1

»° or μ = 1 are defined. The computing circuit 8

* now selects such values of the parameters V or μ that the superimposition of the corresponding curves 20, 21, 22 in FIG. 2 exactly match the specified runtime function 19 at the frequencies 6, 7, 23. Usually

»5 is also a good approximation of the rest Curve in the rectification area. The worst approximation is at the middle frequencies /, 32 and / 33 exist. If at these frequencies the given rest of the latency time difference is

is exceeded, a fine equalization sets in is shown in FIG.

To determine the remaining transit time deviation, the receiving side transit time measuring station 2 is used in F i g. 1 is now switched behind the roughly set equalizer 15.

The computing circuit 8 is expanded by an additional device 34 whose input variables are also available Lfibih F (ZJ 35

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measured remaining transit time deviations F (ZJ 35 and F (/) 36 at the middle frequencies / _t 32 and / 33 and the value of the parameter μΙΟ. In the additional device 34, the values of the parameters μ 37 and //, 38 are calculated, the in turn control the two follow-up regulators 39 and 40. The follow-up regulators 39 and 40 change the frequency-dependent elements

of the partial equalizer 14, which raise or lower the generated by the value of the parameter μ 10 Runtime kui ve at the middle frequencies 32 and 33 cause

The measurement of the delay time distortion of the remote

So speaking channel with at least 2 but at most 4 measuring frequencies is sufficient to use a technically simple arithmetic circuit to generate equalization curves from predetermined values Automatically select families of curves and change their location to achieve the desired rectification to reach.

In addition 5 sheets of drawings

Claims (1)

ÄäTÄa IBSSSS claims 1 and 2, characterized in that by measuring the crack uptime distortion at 2 other 3 » Snte ^ Ln an additional fine equalization is achieved. ^ A ^^ gg further part equalizer generated uite Uufzeitfunktion the remote