JPH02239731A - Automatic equalizer - Google Patents

Abstract

PURPOSE:To set a parameter automatically to optimum by setting a parameter of an equalizer so as to decrease an error rate based on the degree of a change in the error rate extracted by an extraction means and giving the setting result to a variable means. CONSTITUTION:A detection means 4 detects an error rate of a digital signal from a data processing circuit 14, forms a data SR representing the detected error rate and gives it to an extraction means 5. The said extraction means 5 extracts the degree of a change in the error rate with respect to a change in parameters C1, C2 and a setting means 6 gives a correction value to preceding values C1, C2 to calculate the parameters C1, C2 of the equalizer 2 newly so as to reduce the error rate. The new parameters C1, C2 set in this way are given to the variable means 3 to vary the parameters C1, C2 and to give them to the equalizer 2. Thus, the parameters C1, C2 of the equalizer 2 are set automatically to be optimum.

Description

[Detailed Description of the Invention] A. INDUSTRIAL APPLICATION FIELD The present invention relates to an equalizer used in a transmission circuit such as a recording/reproducing device or a communication device, and particularly relates to an automatic equalizer in which parameters are automatically and optimally set. ．． B. Summary of the Invention The present invention is an automatic equalizer used in a transmission circuit of a recording/reproducing device, a communication device, etc., by varying the parameters of the equalizer, extracting the degree of change in error rate, and calculating the error rate. The parameters are set optimally based on the degree of change. C. Conventional Technology Equalizers are generally used in transmission circuits such as recording/reproducing devices and communication devices to reduce distortion in analog signals and errors in digital data. Conventionally, the parameters that determine the characteristics of such equalizers have been properly adjusted and fixed at the time of product shipment. D. Problem to be Solved by the Invention However, if the equalizer parameters are fixed, the temperature,
It has the disadvantage that it is not only unable to follow changes in characteristics due to environmental changes such as time and humidity, but also cannot respond to changes over time in circuits, variations in recording media, etc. To overcome these drawbacks, an automatic equalizer has been proposed that automatically changes parameters in response to changes in the waveform pattern of a synchronization signal, etc., to always obtain optimal characteristics. However, such automatic equalizers have drawbacks such as poor responsiveness because they require complex processing, and high costs because they require large-scale circuits. The present invention was proposed in view of the above circumstances, and aims to provide a practical automatic equalizer in which parameters are automatically and optimally set. E. Means for Solving the Problems In order to achieve the above-mentioned object, an automatic equalizer according to the present invention includes an equalizer whose parameters are freely variable, and a variable means for varying the parameters of the equalizer within a predetermined range. and a detection means for detecting an error rate for the output of the equalizer, an extraction means for extracting the degree of change in the error rate in the parameter varied by the variable means, and an error extracted by the extraction means. and setting means for setting the parameters of the equalizer so as to reduce the error rate based on the degree of change in the rate, and applying the parameter to the variable means. F. Operation: In the automatic equalizer according to the present invention, the parameters set by the setting means are varied within a predetermined range by the variable means and applied to the equalizer. The equalizer outputs an output according to the changed parameters, and the error rate is detected by the detection means. From the change in the error rate of the output according to the change in the parameters of the equalizer, the degree of change in the error rate with respect to the change in the parameter is extracted by an extraction means, and the error rate is determined based on the degree of change in the error rate. The parameters of the equalizer are set by the setting means so that the ratio is small. Then, by applying the set parameters to the equalizer via the variable means, the error rate is minimized, that is, the parameters of the equalizer are optimized. G. EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a case where the automatic equalizer according to the present invention is applied to a reproduction transmission circuit of a recording and reproduction apparatus. The automatic equalizer 1 shown in FIG.
1 through analog-to-digital (A/D) conversion circuit l
2, is converted into a digital signal by this A/D conversion circuit 12, and is supplied. Furthermore, this automatic equalizer l outputs a digital signal that has been subjected to equalization processing, and outputs P
The signal is transmitted to the data processing circuit l4 via the L L (Phaso Locked Loop) circuit l3. The automatic equalizer l includes the A/D conversion circuit B12 and the P
An equalizer 2 connected between the LL circuit 13 and variable means 3 provided for setting parameters of the equalizer 2. It is composed of a detection means 4, an extraction means 5, and a setting means 6. Among these, the equalizer 2 is, for example, C+.
This is an FIR type digital filter whose characteristics are controlled by three parameters, Cz and Cs, in which each of the above parameters Ct. Cz. It is configured to give equalization characteristics according to Cx and send it to the PLL circuit 13 described above. In such an equalizer 2, for example, as shown in FIG. 2 and 3 multipliers 25 and 26, respectively, and the parameters CI
,C. ,C. After weighting is done according to the adder 2
7 and output through the output terminal 28 can be used. In this automatic equalizer 1, each parameter C. ,C. ,C. , the parameter C, is always fixed to a predetermined value, and the parameter C,,C! is freely variable. These variable parameters C,,C. is adapted to be varied according to the output from the variable means 3.

The variable means 3 controls the parameters C, , C., which are set by the setting means 6 as described later. is varied within a predetermined minute range every predetermined short period, and the parameter C of the equalizer 2 is
It is now given as I and CI. This parameter C. ,C. For example, as shown using the coordinates in FIG.
C ++1, C I ) (hereinafter referred to as the value ■), (
C++1, Cz+1) (hereinafter referred to as the value ■),
(Cl, Cz+1) (Hereinafter referred to as value ■.) Repeat the process from the above value ■ to the above value ■ to set the neighborhood of the above value ■ to a predetermined 1! One that vibrates orthogonally by l (1 in this case) is effective for high-speed operation. When the above-mentioned values ■ to values ■ are sequentially given as the parameters C+ and Cz, the equalizer 2 performs equalization processing on the digital signal according to the values and outputs the data from the PLL circuit 13 in the subsequent stage to the data processing circuit. Send to 14th. A part of the digital signal sent to this data processing circuit l4 is
The signal is again supplied to the automatic equalizer 1 and sent to the detection means 4.

The detection means 4 detects the error rate of the digital signal from the data processing circuit 14, forms data SR indicating the detected error rate, and supplies it to the extraction means 5.

The extracting means 5 is supplied with data indicating the value ■ from the value ■ from the variable means 3, and takes in the data SR indicating the error rate when the value ■ is between the value ■ and the value ■. Each error rate SR■ for each value■ to value■
～SR■ is detected. From the results, the following formula ΔSR (SR■+SR■)−(SR■+SR■)Δ
The degree of change () in the error rate ΔSR with respect to the change in the parameter C1 is extracted using C+2, and the parameter C! is calculated using the following formula ΔC, The setting means 6 calculates the parameter C1 of the equalizer 2 anew so that the error rate becomes smaller by using the following equation ΔC1 ΔSR, and , the following formula ΔSR Cm +K (K is a proportionality constant) ΔC, ΔSR The parameter C2 of the equalizer 2 is calculated. Note that such new parameter calculation processing is not limited to linear processing, but may be nonlinear processing as long as good characteristics can be obtained.

The new parameters set in this way (C, .C
．． ) is given to the variable means 3. Then, the variable means 3 varies the new parameters (C+, Cz) as described above and supplies them to the equalizer 2. In the automatic equalizer L, the parameter C of the equalizer 2 is adjusted so that the error rate of the output of the equalizer 2 is reduced by repeating such operations by the respective means.
I and Cx change automatically. Finally, the parameters C+ and C2 of the equalizer 2 are automatically set so that the error rate is minimized, that is, the parameters C+ and C2 of the equalizer 2 are optimized.

Moreover, the automatic equalizer l calculates the parameters C, . C! Since the system is configured to set , it can be realized with a simple circuit configuration, making the system smaller and lower in cost. Furthermore, as mentioned above, the parameters CI of equalizer 1,
C! can be calculated with simple processing, so it is possible to converge to the optimal parameters quickly. In this way, the above-mentioned automatic equalizer l is highly practical. Note that the above embodiment is an automatic equalizer 1 that handles digital signals.
As described above, it is also possible to realize automatic equalizers that handle analog signals by detecting the error rate of the output of the analog equalizer using digital signal processing, etc., and performing similar processing. ．． H. Effects of the Invention Since the automatic equalizer according to the present invention is configured as described above, it has the following excellent effects. First, since the equalizer parameters are automatically set to the optimum value, it is possible to follow changes in characteristics due to environmental changes, and it also automatically responds to changes in circuits over time, variations in recording media, etc. be able to. Therefore, by using the automatic equalizer described above, it is possible to realize a system with excellent interchangeability and high reliability. Furthermore, since it is configured to set the equalizer parameters based on the degree of change in the error rate, it can be implemented with a simple circuit configuration, which helps reduce system size and cost. Furthermore, since the equalizer parameters can be calculated through simple processing, it is possible to quickly converge to the optimal parameters. In particular, by using the variable method of orthogonally oscillating the parameters as described above, it is possible to set the optimal parameters very quickly.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an automatic equalizer according to the present invention, FIG. 2 is a block diagram showing an example of the configuration of an equalizer used in the above automatic equalizer, and FIG. 3 is a block diagram showing the configuration of an equalizer used in the above automatic equalizer. FIG. 2 is a diagram for explaining the variation of parameters using coordinates. l...Auto equalizer 2...Equalizer 3...Variable means 4...Detection means 5...Extraction means 6...Setting means

Claims (1)

[Scope of Claims] An equalizer whose parameters are variable; variable means for varying the parameters of the equalizer within a predetermined range; detection means for detecting the error rate of the output of the equalizer; an extraction means for extracting the degree of change in the error rate in the parameter varied by the variable means; and an equalizer for reducing the error rate based on the degree of change in the error rate extracted by the extraction means. and setting means for setting the parameters of and applying them to the variable means.