JPS62133828A - Signal quality detection method - Google Patents

Abstract

PURPOSE:To quicken the pull-in speed of a signal quality evaluation circuit and to evaluate the signal quality of a line even top a short training signal by using an eye deterioration rate based on a reception signal so as to setting the initial value of an integration circuit. CONSTITUTION:A reception signal is inputted to an equalization circuit 1, an equalization signal of phase and amplitude is fed to a decision circuit 2 and a decided result signal is outputted. Further, the equalization signal and the decided result signal are inputted to an adder circuit 3, an error signal corresponding to an error of the both is generated and fed to a calculation circuit 4. The circuit 4 calculates the eye deterioration rate when the impulse response method to the equalization circuit 1 to generate a prescribed initializing signal corresponding to the eye deterioration rate. The initializing signal is used to set the initial value of the integration circuit constituting the signal quality evaluation circuit 5. Thus, the quality evaluation signal in a form corresponding to the error signal is generated quickly.

Description

[Detailed Description of the Invention] [Summary] In a signal quality detection method that detects signal quality based on the error between a signal obtained by equalizing a received signal and a judgment signal that judges this equalized signal, the signal quality An evaluation circuit and an eye deterioration rate calculation circuit are provided, and an initial value of an integrating circuit constituting the signal quality evaluation circuit is set in accordance with the eye deterioration rate calculated by the eye deterioration rate calculation circuit, and the signal quality is A quality evaluation signal detected by the evaluation circuit is output.

[Industrial application field]

The present invention relates to a signal quality detection method that quickly performs pull-in when detecting signal quality.

[Problems to be solved by conventional technology and invention] Conventionally,
Phase modulated data is received by a modem through a data transmission line, and the phase and amplitude are equalized through an equalizer. When evaluating the line quality of a modem that includes this type of flower vase, there is a method that performs integral processing on the error of the equalized signal obtained by equalizing the received signal (for example,
issue).

In order to output such evaluation signals, statistical processing called integration processing was performed using an integrating circuit, as in the case of fast polling modems, for example.
The problem is that when the duration of the training signal is short, for example, several ms to several + ms, the SQD circuit (signal quality detection circuit) does not sufficiently capture the signal, making it impossible to detect and evaluate the signal quality. was there.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention uses an eye deterioration rate calculated based on the error between an equalized signal obtained by equalizing a received signal and a judgment signal obtained by judging this equalized signal to improve signal quality. By adopting a configuration in which the initial value of the integrating circuit that constitutes the evaluation circuit is set, the acquisition speed of the signal quality evaluation circuit is increased and the signal quality of the line can be evaluated even for short training signals. ing.

FIG. 1 shows a basic configuration diagram of the present invention. In the figure, 1 is an equalization circuit that equalizes the phase and amplitude of the received signal, 2 is a determination circuit, 3 is an addition circuit, 4 is an eye deterioration rate calculation circuit, and 5 is SQ
D (signal quality detection) represents the evaluation circuit.

In FIG. 1, the eye deterioration rate calculation circuit 4 includes the equalization circuit 1
As will be described later, an error signal consisting of the difference between the equalized signal (contains an error) whose phase and amplitude have been equalized by This is to generate an initialization signal corresponding to the eye deterioration rate calculated as follows. This initialization signal sets an initial value for the integrating circuit that constitutes the SQD evaluation circuit 5.

As will be described later, the SQD evaluation circuit 5 generates a quality evaluation signal for evaluating line quality using the error signal manually.

[Effect]

When the configuration shown in FIG. 1 is adopted and the received signal is input to the equalization circuit 1, the equalization circuit 1 equalizes the phase and amplitude.
Sends an equalized signal. This sent out equalized signal is judged by the judgment circuit 2, and a judgment result signal is sent out.

On the other hand, by inputting the equalization signal and the determination result signal to the adder circuit 3 with the illustrated polarities, an error signal corresponding to the error between the two is generated. This generated error signal is input to the eye deterioration rate calculation circuit 4, and the eye deterioration rate when the impulse response method is applied to the equalization circuit is calculated. A predetermined initialization signal corresponding to this calculated eye deterioration rate is generated, and using this generated initialization signal, the SQD
The initial value of the integrating circuit constituting the evaluation circuit 5 is set. Therefore, a quality evaluation signal corresponding to the error signal manually input to the SQD evaluation circuit 5 is quickly generated, and a quality evaluation signal that is sufficiently drawn in even for a short training signal is output.

As explained above, S
For the QD evaluation circuit, a configuration is adopted in which an initialization signal corresponding to the eye deterioration rate calculated using the impulse response method is supplied to the integrating circuit forming the SQD evaluation circuit to forcibly set an initial value. By using the averaging method, S
The QD evaluation circuit is quickly pulled in, and thereafter it becomes possible to stably generate and output quality evaluation signals even for short training signals.

〔Example〕

The configuration and operation of the eye deterioration rate calculation circuit 4 in FIG. 1 will be explained in detail using FIGS. 2 to 5.

Figure 2 shows an illustration of the operational concept of the impulse response method, Figure 2 (a) shows the impulse response waveform when there is no EYE deterioration, and Figure 2 (b) shows the impulse response waveform when there is eye deterioration. The impulse response waveform is shown. As can be seen from both figures, the amount of deterioration of the impulse response is dependent on the slope and the SQD value (
signal quality evaluation value) can be calculated. A detailed explanation will be given below.

First, the cumulative sum of absolute values of errors 0 to +23rd order in the final round of inverse matrix calculation is calculated. This corresponds to 0, ■, ■ written in the impulse response waveform in Figure 3.
. . @ and 1.3 . . . 23 may be calculated, respectively, and the cumulative sum of absolute values may be calculated.

Second, the eye deterioration rate Ec is calculated from the above values using the following formula.

E C=(Σl St l −l So l)/l
So l xlOOχ After normalizing the value of Ec, E c =22/(3(1+(2)")
))(ΣIE i l), Next).

Thirdly, when determining the equalization circuit of the eye deterioration rate calculation circuit 4,
What is shown in FIG. 4(a) is obtained. In the figure, N3 is a normalization coefficient. Furthermore, when this is implemented, an equalization circuit shown in FIG. 4(b) can be obtained. In the diagram! As shown in FIG. 5, SQD has a value that depends on the transmission speed.

Using the equalization circuit generated as described above, the eye deterioration rate Ec corresponding to the impulse response method is calculated from the error signal, and then the calculated eye deterioration rate E,
Calculate the SQD value from

Then, generate an initialization signal corresponding to this SQD value,
The signal is supplied to an integrating circuit constituting an SQD evaluation circuit 5, which will be described next, to switch taps, for example.

FIG. 6 shows the SQD evaluation circuit 5, in which the aforementioned eye deterioration rate calculation circuit 4 Initialization signal supplied from (
Initialization signal) initializes the SQD value calculated by the impulse response method. Therefore, the illustrated SQD evaluation circuit 5 in FIG. 6 can quickly detect the line quality and send it out as an illustrated quality evaluation signal. The configuration and operation will be briefly explained below.

In FIG. 6, the error signal IE is input to a scalar value conversion circuit 12 via a multiplier 11 which serves as an output feedback point. The scalar value conversion circuit 12 creates the square value or absolute value of the amplitude value in order to convert the error signal IE (including the hector quantity, the phase error component and the amplitude error component in the signal) into power. As a result, the error signal IE is expressed as an absolute quantity that does not include an imaginary value, and can be managed with a single real value without having to be managed with both a real part and an imaginary part.

This scalar value is input to the next adder 13 and subtracted from the reference value B0 corresponding to the equalized output. The reference value B0 is set to about 1/2 of the calculation limit width. Therefore, the output of the adder 13 indicates how much the scalar value of the input error signal IE differs from the median value of the preset calculation limit width, for example, the average line error. becomes.

The output of the adder 13 is converted into a control constant T by a multiplier 14.

is multiplied. The output of the multiplier 14 is inputted into the adder 15, which is a 15-tone, 16-tone signal.

Therefore, this integrator circuit operates in either the positive or negative direction until the amount of difference from the reference value B0 for a plurality of error signals that are continuously input becomes the same direction (because the polarity is either positive or negative). or increase in one direction. On the other hand, the greater the deterioration of the line, the greater the reference value B. The amount of difference with respect to will appear as positive or negative, and its integral amount will become a smaller value toward zero. At this time, Figures 2 to 5
Since the value corresponding to the SQD value calculated using the impulse response method explained using the diagram is inputted as an initialization signal to the feedback gain circuit 16 that constitutes the integrator circuit, the integrator circuit operates extremely quickly. state and can generate significant values.

The integral output from the integrating circuit is further multiplied by a control force constant γ1 in a multiplier 17, and the difference from the reference value C6 is calculated in an adder 18. Thereby, the amount of feedback to the multiplier 11 can be adjusted. This value is then supplied to the adding section 19. The output C of this feedback loop is obtained as an analog quantity when the error signal is small and line deterioration is small, the value of C becomes large, and when the error signal is large and line deterioration is large, C rapidly decreases. . In order to output the output C of this circuit as a binary digital quantity, an adder 19 takes the difference from the reference value D0 determined by the error rate and outputs a binary quality evaluation signal, which is used to evaluate the quality of the line. It will be done.

〔Effect of the invention〕

As described above, according to the present invention, signal quality is evaluated using an eye deterioration rate calculated based on the error between an equalized signal obtained by equalizing a received signal and a judgment signal obtained by determining this equalized signal. Since the configuration is adopted in which the initial value of the integrating circuit constituting the circuit is set, the pull-in speed of the signal quality evaluation circuit can be increased. Therefore, even if the duration of the training signal included in the received signal is extremely short, for example, several ms to several + ms, the line quality can be evaluated with sufficient stability.

[Brief explanation of drawings]

Figure 1 is a diagram showing the basic configuration of the present invention, Figure 2 is a diagram explaining the operational concept of the impulse response method, Figure 3 is a diagram explaining eye deterioration rate calculation, Figure 4 is an example of an eye deterioration rate calculation circuit, and Figure 5. 6 shows an example of parameters for an eye deterioration rate calculation circuit, and FIG. 6 shows an SQD evaluation circuit. In the figure, ■ represents an equalization circuit that equalizes the phase and amplitude of the received signal, 2 represents a determination circuit, 3 represents an addition circuit, 4 represents an eye deterioration rate calculation circuit, and 5 represents an SQD evaluation circuit.

Claims (1)

[Claims] In a signal quality detection method that detects signal quality based on an error between a signal obtained by equalizing a received signal and a judgment signal obtained by determining this equalized signal, an error corresponding to the error is provided. a signal quality evaluation circuit (5) that converts a signal into a scalar value and generates an integral value according to the converted scalar value; and an eye deterioration rate that calculates an eye deterioration rate using an error signal corresponding to the error. a calculation circuit (4), and sets an initial value of an integrating circuit constituting the signal quality evaluation circuit (5) in accordance with the eye deterioration rate calculated by the eye deterioration rate calculation circuit (4), and A signal quality detection method characterized by being configured to output a quality evaluation signal detected by a signal quality evaluation circuit (5).