JPS5929018B2 - Multi-signal error detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting an error from a normal value of each signal that is the basis of control in a feedback control device that maintains the values of a plurality of signals at preset values. It is something.

Control to maintain the values of multiple signals is performed by detecting each level of multiple in-band pilot signals and performing feedback control (feedback control) for ultra-wideband FDM line level control.
(ontrol), or when performing (P
Keying for hase-shift) When a modulated wave is captured as a transition process of four points in a phase plane expressed by two orthogonal axes, the phase control of the carrier wave is performed by moving these four points to preset positions on the phase plane. This can be seen in cases where something is done to maintain the situation.

Of the above two examples, the former is an example in which a plurality of signals can be observed simultaneously, and independent feedback control is performed on each signal.

The latter is an example in which each signal can be observed only in time series, and in this case, the order in which each signal appears is often irregular.

However, the disturbance that causes errors in each signal is due to a single common factor called phase shift, and one phase control device operates based on the output of the multi-signal error detector.

In conventional control over a plurality of signals, the number of signals to be handled is not large, or the relationship between the signals is somehow simple, so error detection is not difficult.

However, QASK (Quadra) in carrier band communication
trueAmplitude-shiftKeying
) When considering carrier wave regeneration of orthogonally modulated waves using multivalued pulses such as Hybrid-Modulation, the structure of these signal points on the phase plane is usually as simple as the above-mentioned 4-phase PSK, and Also, the number of signal points is not small.

Therefore, error detection based on control over a plurality of signals naturally becomes complicated, resulting in increased processing time and complexity of the apparatus. In order to avoid complicating the device, there is also a method of detecting only the polarity of the error.

In this case, since the error detection is binary, the control gain of the control device depends on the magnitude of the error, and the steady-state characteristics against noise (noise bandwidth, the size of the compensation output for small errors) and the error against It becomes impossible to provide satisfactory characteristics in terms of quick convergence characteristics (size of compensation output for large errors). To solve this problem, it is necessary to perform analog error detection according to the magnitude of the error within a certain error range. An object of the present invention is to provide a multi-signal error detection device that detects errors from normal values for a plurality of signals using a simpler procedure and with sufficient accuracy.

According to this invention, it is possible to detect errors from their respective normal values for a large number of signals whose mutual relationships are not simple.
Among the signal groups, precise error detection is performed only on some specific signals whose errors are relatively easy to detect, and coarse error detection is performed on other signals whose errors are relatively difficult to detect. Weighting and correction are performed based on the results of precise error detection performed on the specific signal, and this is used as an error for signals other than the specific signal, and the error from the normal value of all signal groups is calculated. , it is possible to provide a multi-signal error detection device that can perform the detection with sufficient precision using a simpler procedure.

Next, the present invention will be explained in detail with reference to the drawings.

First, a case where a signal group can only be observed in time series will be explained using carrier synchronization in QASK as an example.

Figure 1 shows the four mapping points on the in-phase and orthogonal planes of the conventional 4-phase PSK, and the direction of carrier phase control on the transmitting side when a signal occurs at a location shifted from the determined mapping position, with arrows. It is shown. In other words, area A105 in the same figure,
If a signal occurs in the area 106, it is assumed that the mapping point 101 has been transmitted, and if a signal occurs in the area 105, the transmitting side carrier phase is rotated clockwise to return it to the correct position. If a signal occurs at the area entrance 106, it is estimated that the transmission side carrier phase needs to be corrected counterclockwise. The above description has been made using the transmitting side carrier phase as a reference, but when controlling the phase of the receiving side recovered carrier wave on the receiving side, the phase is controlled in the opposite direction. Like this n
In the case of phase-1 PSK, phase control is possible using only information about the angle (phase) from the center of the mapping points arranged on the circumference. However, nine mapping points 201 to 2 as shown in Figure 2
09, the phase control method performed with n-phase 1-PSK is no longer used. ．． , That is, when detecting the phase difference, amplitude information of the input signal is also required. However, in this example as well, since the nine mapped points are arranged on two concentric circles, the phase difference can be detected using the conventional technique. However, as shown in Figure 3, 10 mapping points 30
In cases where numbers 1 to 310 appear to be arranged randomly, multilevel pulse orthogonal modulation, in other words, focuses on the existence of a finite number of mapped points on a two-dimensional plane, and determines the location and arrival of predetermined mapped points. A method of detecting a positional shift of a mapped point detected from a signal by pattern matching is a general method and is excellent in terms of equipment simplification. The + and - symbols in the figure indicate the phase control direction when a signal occurs in the region indicated by the symbol, with + indicating counterclockwise and 1 indicating clockwise. As is clear from this figure, it is relatively easy to detect in which direction the positions of the arriving mapped point and the regular mapped point are shifted, but it is difficult to quantitatively detect the shift with a simple device. Can not. The present invention provides an answer to this problem. FIG. 4 is a block diagram of an embodiment of the present invention for the multilevel pulse quadrature modulation shown in FIG.

First, the in-phase and quadrature components of the multi-level pulse quadrature modulated wave are separately input to input terminals 100 and 101 and digitally coded by analog-to-digital converters 401 and 401', respectively.

These digital codes each represent the coordinates of the position of the mapping point of the incoming signal on the in-phase, orthogonal, or two-dimensional plane. These digital codes are input in parallel to read-only memories (hereinafter abbreviated as ROM) 402, 403, and 404. Of the three ROMs, ROM4O2 contains information as shown in FIG. 5, with in-phase coordinates taken on the horizontal axis and orthogonal side coordinates taken on the vertical axis.

This information represents the region in which the mapped point 304 in FIG. 3 should occur. That is, the ROM 402 detects the mapping point 304 among the 10 mapping points detected from the incoming signal, and only when the mapping point 304 is detected, the memory 405
Issue a read command to. The memory 405 continues to hold the content just read until the next read command. The ROM 4O3 has contents such that the actual reception coordinates Xl, y of the mapping point 304 are used as addresses, and the phase shift θe(X, y) Rad corresponding thereto is outputted.

Input continues to be input to this ROM4O3,
Meaningful phase information is provided only for the mapped point 304. The output of this ROM4O3 is input to the memory 405 and read into the memory only by the detection signal of the mapping point 304 from the ROM4O2. Above ROM4O2, ROM
4O3, memory 405 constitutes precision error detector 500. ROM4O4, like ROM4O2, contains information as shown in Figure 6, with the in-phase coordinates on the horizontal axis and the orthogonal side coordinates on the vertical axis, and when a signal occurs in the hatched area, a white signal appears in the counterclockwise direction. When a signal occurs in the area, it outputs an output to correct the phase clockwise. In other words, it is a phase comparator with binary output. This is the coarse error detector. This output is input to a multiplier 406 which is a load corrector, and is input to a memory 40
This is multiplied by the latest precise phase error obtained based on the mapping point 304 held at 5, multi-valued, and then outputted from the carrier phase detection device of the present invention and sent to the output terminal 102. to go out. Next, consider a case where five mapping points are set as shown in FIG.

It can be seen from this figure that it is convenient to precisely perform phase detection at the mapping point 704.

If it is assumed that offset control of the incoming signal is performed, the abscissa value of the signal occurring in area 706 in the same figure, with the opposite polarity (-x), can be made to directly correspond to the phase error. can. Therefore, the role of precise phase error detection θe(X,y), which was played by ROM4O3 in the embodiment shown in FIG. 4, is no longer required. Figure 8 shows the 7th
FIG. 6 is a block diagram of another embodiment of the present invention when the five mapped points shown in the figure are sent;

As in the embodiment of FIG. 4, the in-phase and quadrature components enter input terminals 100 and 101 separately and are digitally coded by analog-to-digital converters 801 and 80, respectively.

This code is input to two ROMs in parallel and ROM8O
2 detects whether the arriving mapping point occurs in area 2 706 in FIG. The memory 805 holds the current value until the next read command. The memory 805 has inputted the abscissa coordinate of the arriving mapped point, and provides precise phase shift information to the mapped point 704 only when the mapped point 704 occurs. Memory 805
and ROM8O3 constitute a precision error detector 501. ROM8O4 contains the contents of ROM4O3 (see Figure 6).
As in the case of Figure 1), contents are written that allow the phase shift of all mapped points to be identified by binary values of + and 1, that is, clockwise and counterclockwise.

It is a coarse error detector. This output enters a multiplier 806 as a load corrector, multiplies it by the magnitude of the phase error precisely detected when the mapping point 704 occurs, multivalues it, and becomes the final output of the carrier phase detection circuit. terminal 10
Go out to 2. The multi-signal error detection device in the synchronous circuit has been described above, but since the control target is the carrier wave phase, the only output of the multi-signal error detection device is phase difference information with respect to the carrier wave.

As described above, according to the present invention, QASK,
It is possible to provide a multi-signal error detection device that can detect errors in carrier wave synchronization of HybridMOdulation with a simple procedure and sufficient accuracy.

In precision error detection, a precision error detector that outputs a detection result after band-limiting it using a filter or the like is also practically conceivable.

The present invention is very useful for carrier wave regeneration for all types of QASK modulated waves that will appear in the future, especially as a phase difference detector for a regeneration device with excellent convergence characteristics.

[Brief explanation of drawings]

Figure 1 shows an example of conventional 4-channel control for multiple signals.
A diagram showing the four mapping points of phase-PSK and their control outputs,
2 and 3 are diagrams showing the mapping point positions of multilevel pulse quadrature modulated waves having 9 and 10 mapping points and their control outputs, and FIG. 4 shows one embodiment of the present invention. In the block diagram shown, analog-to-digital converters 401 and 40', a precision error detector 500, and a ROM 4O as a coarse error detector are shown.
4. Consists of a multiplier 406 as a load corrector.

Claims (1)

[Claims] 1. A multi-signal error detection device that detects a deviation from a normal value of a plurality of signals due to a disturbance factor, which detects a precision error that is a deviation from a normal value of some signals among the plurality of signals. a coarse error detector that detects the polarity of deviation from a normal value of each signal for the plurality of signals, and an output of the fine error detector as the output of the coarse error detector. and a load corrector that multivalues the output of the coarse error detector by multiplying the output, and outputs the output of the load corrector as an error from the normal value of the plurality of signals. Error detection device.