JPS60248032A - Automatic equalizer - Google Patents

Abstract

PURPOSE:To equalize properly a flat loss easily with simple constitution by extracting a signal required for compensating the flat loss from a burst signal transmitted from the transmission side to control a flat gain amplifier. CONSTITUTION:A reception information signal S1 of the burst mode received to an input terminal 100 is inputted to a flat gain amplifier section 11 and a supervisory signal extracting section 22. The extracting section 22 extracts at least one supervisory signal from the signal S1 and inputs it to a flat gain control section 21. The control section 21 compares the input supervisory signal with a prescribed value and outputs a control signal so that the gain corresponding to the said difference is compensated by the amplifier section 11. The amplifier 11 outputs an information signal S2 where the flat loss is equalized and it is inputted to a slope gain amplifier section 31. A slope gain control section 41 inputs an output information signal S3 of the amplifier section 31, controls the gain of the amplifier section 31 so that the signal S3 is a prescribed amplitude based thereupon and converges the slope loss so as to be equalized properly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a transmission system in which information is sent and received through time-division direction control via a subscriber line transmission line, and the present invention is directed to The present invention relates to an automatic equalizer that compensates for loss and slope loss separately [7], and particularly relates to an automatic equalizer that controls the equalization amount for flat loss using a monitoring signal extracted from a burst signal.

(Prior art) Losses occurring in subscriber line transmission lines connecting exchanges and subscribers include constant loss (hereinafter referred to as flat loss) LF that is independent of frequency f, and loss that attenuates as frequency f increases. There is a loss (hereinafter referred to as slope loss) LS (f+) whose slope is proportional to q.

In addition, both flat loss and slope loss are 44 (class 44) of the line.

I is related to the diameter, length, etc., and varies depending on the combination thereof.

Furthermore, since the correlation between flat loss and slope loss is not unique, equalization of flat loss and slope loss are performed separately.
An independently controlled automatic equalizer is preferred.

Conventionally, this type of automatic equalizer was used in the 1985 IEICE General Conference Lecture Proceedings Volume 1゜Paper No. 231.
4, a method for configuring a v'7 equalizer is proposed. In this automatic equalization amount, the flat gain amplification means and the slope gain amplification means are provided separately, but the peak voltage of the equalization amount output is detected,
Loss equalization is performed by controlling the flat gain amplification means and the slope gain amplification means using the peak voltage according to a preset distribution law of the equalization amount of flat loss and the equalization amount of slope loss.

(Problem to be Solved by the Invention) In this way, the conventional automatic equalizer cannot uniquely equalize flat loss and slope loss, and must allow a certain amount of equalization residual. There is a drawback.

(Means for Solving the Problems) The automatic equalizer of the present invention is configured to transmit an equalization signal from the transmitting side at an equalization amount that individually compensates for the flat loss and slope loss occurring in the subscriber line transmission line. flattening gain control means for extracting a signal component (monitoring signal) 1 necessary to compensate for flattening loss from the burst signal and outputting a control signal for equalizing flattening loss by the extracted signal component; The present invention includes flat gain amplification means that performs flat amplification with respect to frequency according to the output signal of the flat gain control means.

(effect) FIG. 1 is a block diagram showing an automatic equalizer of the present invention.

This automatic equalization branch includes a flat gain amplification means 1 that equalizes flat loss that is not dependent on frequency but mainly depends on line type and line length, and a monitoring signal from among the burst signals inputted to the input terminal 100. flat gain control means 2 for controlling the flat gain amplification means 1 so as to extract and compensate for the flat loss according to the extracted monitoring signal; and a slope gain amplification means 3 for equalizing the slope loss exhibiting frequency dependence. , for example, includes a slope gain control means 4 for controlling the reverse slope gain amplification means 3 by a peak value detection control type control, and the flat loss and slope loss of the signal input to the input terminal 100 are compensated for and the signal is output to the output terminal. 200.

As can be seen from FIGS. 2(a-1) to (c), the loss in the subscriber line transmission line is dominated by flat loss in the low range, and is dominated by slope loss in the high range.

Therefore, a signal having a frequency within a band where flat loss is dominant (hereinafter referred to as a flat loss region) is received as a signal attenuated by the flat loss.

Figure 3 shows the power spectrum of an information signal in a commonly used transmission code format.When transmitting and receiving information using time-division direction control (also called burst mode), it is transmitted at a past cycle Tb. Then, a coarse spectrum of burst frequency fb(=,ri,) appears.

It is obvious that in the time-division direction control transmission system, the burst frequency fb and the information signal sending frequency, fs, have a relationship of fb≦fs. Therefore, the burst frequency fb can be separated from (il information signal) without mutual influence.
The burst frequency f can be selected in a low range so that it can be extracted and treated as a signal within the 1υ flat loss region.Not only the burst frequency f, but also the harmonics of the burst frequency fb that satisfy the above two conditions The component can also be received and extracted as a signal attenuated by the flat loss, and is useful as a signal (monitoring signal) for obtaining control information necessary for equalizing the flat loss.

(Embodiment) Fig. 4 is a block diagram showing a first embodiment of the present invention. However, in the following embodiments, parts having similar functions to those in this embodiment are designated by the same numbers.

The burst mode reception information signal S1 received at the input terminal 100 is input to the flat gain amplification section 11 and the monitoring signal extraction section 22. The supervisory signal extractor 22 extracts at least one supervisory signal from the input information signal and inputs it to the flat gain controller 21 . The flat gain control unit 21 compares at least one input monitoring signal with a predetermined value, and calculates a gain amount according to the error (however, the gain amount described here indicates the amount of amplification and attenuation). A control signal is output so that the flat gain amplification section 11 compensates.

Therefore, the flat gain amplification section 11 to which the control signal is input,
It is set so that flat loss can be properly equalized.

Therefore, the flat gain amplification section 11 which receives the information signal S1 outputs the information signal S2 whose flat loss is equalized.

The information signal S2 is input to the slope gain amplification section 31 via the connection point 400. In the initial state, since the gain amount of the slope gain amplification section 31 is not set appropriately, the output information signal S3 of the slope gain amplification section 31 is incompletely compensated for the slope loss.

The information signal S3 is input to the slope gain control unit 41, and the slope gain control unit 41 controls the gain amount of the slope gain amplification unit 31 based on the information signal S3f so that the information signal S3 has a predetermined amplitude. and converge to properly equalize the slope loss. In a state in which the gain amount of each of the flat gain amplifying section 11 and the slope gain amplifying section 31 has converged to an appropriate value, an information signal S3 in which the flat loss and the slope April loss have been appropriately equalized is output from the output terminal 200. is output, and automatic equalization of flat loss and slope loss has been performed.

FIG. 5 is a block diagram showing a second embodiment of the present invention. The received information signal S1 is input to the flat gain amplification section 11. In the initial state, the gain amount of the flat gain amplifying section 11 is not properly set, so that the output s2 of the flat gain amplifying section 11 is incompletely compensated for the flat gain amplifying section 11 loss.

At least one supervisory signal is extracted from the output S2 of the flat gain amplifier 11 by the supervisory signal extractor 22.

The monitoring signal is input to the flat gain control unit 21, and the flat gain control unit 21 controls the gain h1 of the flat gain amplification unit 11 so that the monitoring signal becomes a predetermined value, and appropriately equalizes the flat loss. Converge like this. In a state where the flat gain amplifying section 11 has converged to an appropriate value, an information signal S2 whose flat loss has been appropriately equalized is outputted from the flat gain amplifying means 1 to the connection point 400.

Regarding the subsequent equalization operation of the slope loss, since the block configuration from the connection point 400 to the output terminal 200 is the same as in the first embodiment, there is no need to describe the slope loss in detail. Automatic equalization of flat loss and slope loss is also performed in .

FIG. 6 is a block diagram showing a third embodiment of the present invention. The information signal S1 received from the input terminal 100 is input to the slope gain amplification section 31. In the initial state, the gain amount of the slope gain amplifying section 31 is not set appropriately, so that the output/information signal S4 is incompletely compensated for the slope loss. From the output of the slope gain amplification section 31, a feedback branch point 300
The block configuration up to this point is the same as the configuration from the input terminal 100 to the connection point 4004 in the first embodiment, so it is not too much to explain in detail, but the first It is clear that the flat loss is equalized by the same series of operations as in the embodiment. Therefore, at the feedback branch point 300, the information signal S whose flat loss has been equalized is
3 is output, and the information signal S3 is input to the slope gain control section 41.

The slope gain control unit 41 controls the slope gain amplification unit 31 so that the input information signal S3 has a predetermined amplitude, and converges to properly equalize the slope loss.

By performing the above series of operations, the gain amounts of the flat gain amplification section 11 and the slope gain amplification section 31 converge to appropriate values, and the flat loss and
It can be seen that the slope loss can be automatically equalized.

FIG. 7 is a block diagram showing a fourth embodiment of the present invention, and automatic equalization of flat loss and slope loss is performed in the second and third embodiments, which need not be described in detail.

(Effects of the Invention) As explained above, the present invention transmits an information signal through a subscriber line transmission line under time-division direction control, and uses a monitoring signal extracted from the received information signal to adjust the gain of the flat gain amplification means. By controlling the amount, the flat loss in the subscriber line transmission line can be equalized, and there is an effect that not only the flat loss but also the slope loss can be appropriately equalized with a simple configuration.

Figure 3 showing an example of the frequency characteristics of loss in a large line transmission line.
The figure shows the electric drop vector in the transmission code format.
7 to 7 are block diagrams showing first to fourth embodiments of the present invention, respectively.

1...Flat gain amplification means, 2...Flat gain control means, 3...Slope gain amplification means, 4.
. . . Slope gain control means, 11 . . . flat gain amplification section, 21 . . . flat gain control section, 22 . . .
Monitoring signal extraction section, 31...Slope gain amplification section, 4
1... Slope gain control section, 100... Input terminal, 200... Output terminal, 300...
...Return branch point, /100...Connection point.

Agent Patent Attorney Susumu Uchihara =',”” −’=′)−
1. Kotobuki/Figure

Claims (1)

[Claims] In an equalizer that separately compensates for the flat loss and slope loss that occur in the subscriber transmission line, the signal components necessary to compensate for the flat loss are extracted from the burst signal sent from the transmitting side. flat gain control means for outputting a control signal for equalizing the flat loss by the signal component obtained by the flat gain control means, and flat gain amplification means for performing flat amplification with respect to frequency according to the output signal of the flat gain control means. An automatic equalizer characterized by: