JPH01200727A - Data transmission equipment - Google Patents

Abstract

PURPOSE:To speed up the convergence of an automatic equalizer and to improve transmitting efficiency by storing the tap coefficient of plural remote side automatic equalizers and using the tap coefficient corresponding to a control signal received from a remote side through a subchannel. CONSTITUTION:Plural memories 21-2n are provided through a switching circuit 3 to a demodulation circuit 1. Optimum tap coefficients found for every respective transmitting lines with plural remote sides in the memories 21-2n. Then, the corresponding memory is selected among the memories 21-2n corresponding to a control signal 13 from the remote side through a subchannel and is connected to an automatic equalizer in the circuit 1. Consequently, when communication with the same remote side is executed again, the tap coefficient stored before is used, the convergence of the automatic equalizer is made quick, and transmitting efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data transmission device including a modem and an automatic equalizer.

[Conventional technology]

For data transmission using pulse signals, an AC signal modulated with a carrier wave is generally used.When receiving this signal, in order to correct transmission distortion such as amplitude distortion and delay distortion caused by the transmission line, recently An automatic equalizer is used, and the optimal tap coefficients of the automatic equalizer are automatically set based on a training signal sent from the other party prior to the start of communication.

FIG. 2 is a block diagram showing the reception side of a conventional example. A demodulation circuit 1 equipped with an automatic equalizer is attached with a memory 2 for storing the tap coefficients of the automatic equalizer, and While the training signal is being given as the received signal 11 through the demodulation circuit 1, the automatic equalizer in the demodulation circuit 1 automatically sets the optimum tap coefficient according to the transmission characteristics of the line used, and stores this in the memory 2. After determining the equalization state using this,
A demodulation circuit 1 demodulates subsequent received signals and sends them out as demodulated output 12.

[Problem to be solved by the invention]

However, the tap coefficient changes depending on the line used between the other parties, and when data is transmitted alternately with multiple parties, the automatic equalizer taps each time according to the other party. The coefficients must be set, and the time required to reach the optimal convergence state is, for example, CCI
160m5e according to segment 3 of TT V, 29
c. During this period, normal reception is impossible, so this convergence time is required each time the other party is changed, resulting in a drawback that overall transmission efficiency is reduced.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention is constructed by the following means.

That is, in the data transmission device described above, there are a plurality of memory circuits that store the tap coefficients of the automatic equalizer, and a corresponding one of the memory circuits is selected according to a control signal received from the other party via a subchannel. and a switching circuit for connecting to an automatic equalizer.

[Effect]

Therefore, tap coefficients for each of a plurality of parties are stored in a plurality of memory circuits, and the tap coefficients of the corresponding memory circuits are used for automatic equalization in response to a control signal from the party via a subchannel. The automatic equalizer will converge more quickly if it is possible.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the block diagram of FIG. 1 showing an embodiment.

In the figure, a plurality of memories 21 are provided for the demodulation circuit 1.
~2n are provided, and a switching circuit 3 is interposed between these and the demodulation circuit 1, and a control signal 13 from the other side via the subchannel is applied to this. There is.

Further, the switching circuit 3 selects a corresponding memory among the memories 21 to 2n in response to a control signal 13 unique to the other party, and connects it to the automatic equalizer in the demodulation circuit 1. , each of the memories 21 to 2n stores the optimal tap coefficient determined for each transmission line between multiple parties, so when communicating with the same party again, the If the previously stored tap coefficients are used by the control signals from the automatic equalizer, convergence of the automatic equalizer will occur immediately.

〔Effect of the invention〕

As is clear from the above description, the present invention includes a plurality of storage circuits for storing tap coefficients of an automatic equalizer, and each storage circuit in response to a control signal received from the other party via a subchannel. By providing a switching circuit that selects the corresponding one among them and connects it to the automatic equalizer, when communicating alternately with multiple parties, the tap coefficient previously stored in the memory circuit can be used. The automatic equalizer converges on the fly using
The overall transmission efficiency is greatly improved, and a remarkable effect can be obtained in a data transmission device equipped with an automatic equalizer.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional example. 1...Fist/demodulation circuit, 2.21~2n...memory,
3...Switching circuit, 11...Received signal, 13...
··Control signal

Claims (1)

[Claims] A data transmission device including an automatic equalizer that automatically equalizes transmission distortion of the line by a signal received via the line, comprising: a plurality of storage circuits for storing tap coefficients of the automatic equalizer; A data transmission device comprising: a switching circuit that selects a corresponding one of the storage circuits and connects it to the automatic equalizer in accordance with a control signal received from the other party via a channel.