JPS6376628A - Semi-fixed equalizer - Google Patents

Abstract

PURPOSE:To automatically correspond to even the subsequent change of a communication line by compensating the waveform deterioration and the delay of a receiving signal for a prescribed time by a generated parameter based on a receiving signal and a setting quantity. CONSTITUTION:A signal detecting means 2 detects the condition of a receiving signal at least at one side of the input side or the output side of a fixed equalizer 1. The receiving signal receives the deterioration of a waveform by transmitting a communication line. The detecting signal is converted by a signal converting means 3 for a prescribed time based on the control signal to show the reference quantity inputted from the external part, the setting time, etc. Based on the converting signal, a parameter generating means 4 generates a parameter to compensate the deterioration for the setting time of the receiving signal and sends it to the fixed equalizer 1. Thus, since corresponding to the distortion of an hourly waveform immediately and without executing the compensation, the deterioration compensation is executed for a prescribed time specified by the control signal, an equalization characteristic can be changed by adjusting the hourly interval, etc., and corresponding to the change of the non-hourly primary factor of a distance, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A semi-fixed equalizer according to the present invention compensates for waveform deterioration and delay of a received signal at predetermined time intervals using generated parameters based on the received signal and a set amount.

As a result, unlike fixed equalizers, the equalization characteristics are not fixed at the time of setting the communication line, and subsequent changes in the communication line due to connection of the communication line etc. do not depend on the operator switching the fixed equalizer. It can respond automatically.

[Industrial application field]

Of the equalizers used for wideband, long-distance transmission, the present invention
This invention relates to a semi-fixed equalizer that is an improved fixed equalizer that compensates for signal waveform deterioration due to signal attenuation.

[Conventional technology]

Conventionally, in complex transmission systems and transmission circuits, signal waveform deterioration generally occurs within the transmission band due to attenuation distortion, etc., but fixed equalizers and automatic equalizers are added circuits to compensate for this. Fixed equalizers primarily compensate for time-invariant signal waveform distortions. On the other hand, an automatic equalizer compensates for temporal distortion due to temperature and other factors, and the range of equalization capability is short (tap length is finite). Therefore, when the distance of the communication line is short, it is possible to handle it with only an automatic equalizer, but when the distance is long, the automatic equalizer alone cannot handle the problem, so automatic equalization is used as shown in Figure 6. Fixed equalizers 61, 62, and 63 are combined with the equalizer 64 to compensate for deterioration in the signal waveform of the received signal.

[Problem that the invention seeks to solve]

By the way, as mentioned above, the fixed equalizers 61, 62, 63 mainly depend on non-temporal factors such as distance (number of repeaters,
To cope with waveform deterioration caused by factors such as the number of lines), several types of fixed equalizers 61, 62, and 63 are prepared depending on the distance of the communication line, etc., and are used when constructing the communication line. The optimum fixed equalizer 61 will be selected and set during the field survey. However, the selection of the fixed equalizers 61, 62, and 63 during field surveys requires a high level of technical ability as the operator can observe and judge the eye pattern, and once set, the fixed equalizers 61, 62, and 63 are fixed. Since the equalizer is limited, the equalization range is also limited.

Therefore, the present invention has been made to solve the above problems, and is a semi-fixed equalizer that does not require the selection of a fixed equalizer during field surveys, etc., and has a wider range of equalization capability than before. It was created for the purpose of providing an equalizer.

[Means for solving problems]

In order to solve the above problems, the present invention, as shown in FIG. A signal converting means 3 that converts a detection signal at predetermined time intervals based on a control signal, a parameter generating means 4 that generates a parameter based on the converted signal, and a fixed device that compensates for deterioration of the received signal waveform based on the parameter. It has an equalizer 1.

[Effect]

In the present invention, the signal detecting means 2 detects the state of the received signal at least on the input side or the output side of the fixed equalizer l. The received signal undergoes waveform deterioration due to transmission through the communication line. The detection signal is converted by the signal converting means 3 at predetermined time intervals based on a control signal input from the outside that indicates a reference amount, a set time, and the like. Based on the converted signal thus converted, the parameter generating means 4 generates a parameter for compensating for the deterioration of the received signal at each set time, and sends it to the fixed equalizer l. As a result, unlike automatic equalizers, the semi-fixed equalizer according to the present invention does not immediately respond to and compensate for temporal waveform distortion, but degrades at predetermined time intervals determined by control signals. In order to compensate, the equalization characteristic can be changed in response to changes in non-temporal factors such as distance by adjusting the time interval and the like.

〔Example〕

Next, embodiments according to the present invention will be described.

FIG. 2 shows a semi-fixed equalizer according to the first embodiment.

The semi-fixed equalizer is composed of a fixed equalizer 11, a signal detection means 12, a signal conversion means 13, and a parameter generation means 14.

A fixed equalizer 11 in the figure receives a received signal and compensates for waveform deterioration of the signal, and the output signal is sent to an automatic equalizer. Further, the fixed equalizer 11 has a plurality of variable parameters, and the parameters are determined by input operations from outside the fixed equalizer 11.

In this embodiment, the signal detecting means 12 detects the received signal from the output side of the fixed equalizer 11, and is composed of a filter 5 and an i gate measuring means 16. The filter 15 detects a received signal of a predetermined frequency from among the received signals.

The level measuring means 16 measures the level of the received signal that has passed through the filter 15, such as the potential.

The signal conversion means 13 includes an adder 17, a multiplier 18, and an adder 1.
9, a delay circuit 20 and a multiplier 21.

A reference amount as a control signal indicating the ideal state of the received signal is inputted to the adder 17 from the outside, and the difference from the detected signal is determined. The control force A as a control signal is also input to the multiplier 18, and the difference between the detection signal obtained by the adder 17 and the reference amount is multiplied. This control force A
is sequence-controlled and is used to convert the difference between the received signal detected by the signal detection means 12 and the reference amount at predetermined time intervals.

The adder 19 and the delay circuit 20 form a loop, and the multiplier 1
Integration is performed by repeatedly adding delayed output signals from 8. The multiplier 21 multiplies the integrated value by the control force B, which is a control signal from the outside, and determines a predetermined time by setting the time for performing the integration. Specifically, the integration is repeated until the value O is input from the outside.

The parameter generating means 14 generates parameters to be sent to the fixed equalizer 11, and the adder 22 and the RO
It is composed of M23.

The adder 22 adds a constant as a control signal from the outside to the converted signal obtained by the signal converting means 13, thereby storing parameters necessary for compensating for the deterioration of the detection signal in a ROM (Read Only Memory) 23. This is for generating an address for reading from. Parameters to be added to the fixed equalizer 11 based on the conversion signal from the signal detection means 13 are stored in the ROM 23 at predetermined addresses.
Parameters corresponding to the output from the fixed equalizer 11 are sent to the fixed equalizer 11.

Here, the principle that the characteristics of the fixed equalizer 11 change depending on one parameter will be explained using a simple filter as an example. In a filter composed of multipliers 51 and 53, an adder 52, and a delay circuit 54 as shown in FIG.
If -α is input, a filter having characteristics as shown in FIG. 4 will be obtained depending on the value of α.

Next, the operation of the semi-solid foot equalizer according to this embodiment will be explained.

In this embodiment, the parameters of the fixed equalizer 11 are adjusted during a certain period of time during a training signal performed prior to data transmission according to, for example, CCITT Recommendation V, 29 to determine its characteristics.

The state of the received signal output from the fixed equalizer 11 is detected by the signal detection means 12. The signal detecting means 12 has a filter 15 that selects a predetermined frequency, and a level measuring means 16 measures the level of the signal.

Then, the signal converting means 13 calculates the difference between the detected signal and an ideal received signal which is a reference amount as a control signal inputted from the outside using an adder 17 thereof, and further calculates the difference between the detected signal and an ideal received signal which is a reference amount as a control signal inputted from the outside in a multiplier 18. Multiply this by the control force A, which is a signal. This product is used to perform control to compensate for the degraded signal waveform at set predetermined time intervals.

Subsequently, an adder 19 and a delay circuit 20 repeatedly delay and add the results obtained by the multiplier 1.8 to perform integration. The integral time as the predetermined time is set by the control force B as an external control signal input to the multiplier 21.

Further, the parameter generation means 14 generates a parameter α1. α2. Output α3. That is, the signal output from the multiplier 21 is transferred to the adder 22 and added to a constant set by an external control signal. As a result, the information stored in the ROM 23 in advance,
The address for reading the parameters necessary to compensate for the signal deterioration is transferred to the ROM 23, and the necessary parameters α1. α2. α3 is output and sent to the fixed equalizer 11. Fixed equalizer ll has this parameter αl.

α2. A predetermined deterioration in the waveform of the received signal is compensated based on α3 and sent to an automatic equalizer.

Next, a second embodiment of the present invention will be described based on FIG. 5.

This embodiment differs from the first embodiment in that it monitors n frequencies and also takes into consideration the characteristics of the connected line.

In this embodiment, unlike the first embodiment, the signal detection means 32 includes n filters 35 and n level measurement means 36. Further, the signal conversion means 33 includes n adders 37
and n multipliers 39, n adders 40. Although this embodiment differs from the first embodiment in that it includes n delay circuits 41 and n multipliers 42, the functions of each device are the same. n
A reference amount representing an ideal received signal is added to each of the adders 37 from the outside as a set amount.

Similarly to the multiplier 18, the control force C as a control signal is input to each of the n multipliers 39 from the outside, and the adder 3
The product with the difference obtained in step 7 is taken.

Also, for each of the n multipliers 42, the product of the control force as a control signal and the integration result is calculated from the outside. Unlike the first embodiment, the parameter generating means 34 generates n parameters α1. α2. α3. ...ROM having αn
It has 44. Similarly to the first embodiment, the n adders 43 each calculate the sum of the conversion signal from the signal conversion means 33 and a constant set by an external control signal, and read out the ROM 44. Each address is generated for each operation.

In addition, in the first and second embodiments, the fixed vase 11.
The received signal is detected from the output side of 31.
In other words, although it is feedback control, the fixed equalizer 11
．． Feedforward control may be performed in which the received signal is detected from the input side of 31. Feedback control generally provides accurate control but slow control speed, whereas feedforward control is relatively coarse but fast control speed. In this embodiment, feedforward control may be used if the input is input to the automatic vase after the semi-fixed vase and further equalization is performed.

〔Effect of the invention〕

In this way, since the semi-fixed equalizer according to the present invention automatically compensates for signal waveform deterioration at each set predetermined time interval, it can also respond to changes in non-temporal factors. Can be done.

Therefore, there is no need for a worker to select a fixed equalizer when constructing a communication line, and this can be done automatically. Further, the equalization ability is not limited by the setting of a fixed equalizer as in the conventional case.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a semi-fixed equalizer according to the first embodiment, Fig. 3 is a diagram showing an example of a parameter-containing filter, and Fig. 4 is an example of filter characteristics. diagram showing,
FIG. 5 is a block diagram showing a semi-fixed equalizer according to the second embodiment, and FIG. 6 is a block diagram showing a conventional example. 1.11.31...Fixed equalizer 2.12.32...Signal detection means 3.13.33...Signal conversion means 4.14.34...Parameter generation means
R Indication 1 F'' 6th [ Lock Diagram

Claims (1)

[Claims] Signal detection means 2 for detecting the state of a received signal on at least one of the input side and output side of the fixed equalizer 1, and converting the detected signal at predetermined time intervals based on an external control signal. A signal converting means 3 for converting the signal, a parameter generating means 4 for generating a parameter based on the converted signal, and a fixed equalizer 1 for compensating for deterioration of the received signal waveform based on the parameter. Semi-fixed equalizer.