JPH02104049A - Code error prediction detection system for digital communication - Google Patents

Abstract

PURPOSE:To predict the generation of a code error based on interference noise by comparing a reception signal including the interference noise with a reception signal not including the noise and outputting a dicordant comparison output in response to the increase in the interference noise. CONSTITUTION:A reception signal from an input 1 is branched, one is given to an automatic waveform equalizer 11, where interference noise is eliminated and a demodulated digital signal is obtained by a demodulator 2 and a code discriminator 3 and sent from an output terminal 4, and the other branched signal is given to a demodulator 12 and a code discriminator 7, from which a demodulated digital signal including the interference noise is obtained, the delay time of the signal with respect to the received signal via the automatic waveform equalizer 11 is adjusted by a delay adjusting device 9 to make the phases of both the signals coincident, the output of the code discriminator 3 and the output of the delay adjusting device 9 are compared by a comparator 8 and the result of comparison is sent from an output terminal 10 as a code error prediction alarm signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a detection method for predicting the occurrence of code errors due to interference noise in digital communication via a transmission line such as a wireless line.

[Conventional technology]

Conventional code error prediction detection methods mainly target the occurrence of code errors due to noise having a saw-like frequency spectrum, such as thermal noise, and the configuration shown in the block diagram shown in Fig. 3 is generally used. There is.

That is, the received codes of input 1 and 2 are demodulated in the demodulator 2, decoded by the code discriminator 3, and sent out as a demodulated digital signal from the output 4, while thermal noise generated in the noise generator 5 is The noise signal and the output of the demodulator 2 are added by an adder 6, the output of which is decoded by a code discriminator 7, this output is given to a comparator 8, and a delay adjuster 9 adds the output of both codes to the code discriminator 3. The delay time difference between the outputs of .7 is adjusted, and the output of the code discriminator 3 via the delay adjuster 9 is also fed to the comparator 8, where the two are compared and the result of this comparison is used as the output 10 and the code discriminator 3. This signal is sent as a false prediction warning signal.

That is, the output of the code discriminator 3 does not contain any noise components, whereas the output of the code discriminator 7 contains no noise components.
A noise component is included, and if the two are compared using a comparator 8 using an exclusive OR circuit, a difference corresponding to the noise component will occur.

On the other hand, if thermal noise is included as line noise in the reception-to-reception signal, the difference between the two will decrease and the comparison output of the comparator 8 will decrease, so it is possible to predict the occurrence of code errors. In other words, it is sufficient to use the signal from the output 10 to warn of the prediction of the occurrence of a code error.・ [Problem to be solved by the invention] However, in the configuration shown in FIG. 3, the output level of the noise generator 5 must be adjusted optimally, which is difficult and also reduces the possibility of code errors caused by thermal noise. This method has the disadvantage that it is only possible to predict, and it is impossible to predict the occurrence of code errors based on interference noise such as code amount interference and inter-channel interference due to deterioration of the transmission frequency characteristics of the transmission line.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention is configured by the following means.

That is, interference noise is removed from the receiving signal 4 through an automatic waveform equalizer, the delay time of this signal with respect to the receiving signal 4 is adjusted, and both signals are compared. Based on the comparison result, a code error prediction warning signal is generated. is assumed to be obtained.

[For production]

Therefore, a comparison is made between the received signal 4 that includes interference noise and the received signal 4 that does not include interference noise, and the comparison outputs become inconsistent as the interference noise increases. can be done.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to FIGS. 1 and 2 showing embodiments.

Figure 1 is a block diagram of the entire configuration.The reception signal 4 from the input 1 is branched, and the - output obtains an 11-tone digital signal from an automatic waveform equalizer, which is sent out from the output 4. A demodulated digital signal containing interference noise is obtained via the demodulator 12 and the code discriminator 7, and the delay adjuster 9 adjusts the delay time for the received signal 4 via the automatic waveform equalizer 11. After matching the phases of the two, the output of the code discriminator 3 and the output of the delay adjuster 9 are compared by the comparator 8, and the comparison result is sent to the output 10 as a code error prediction alarm signal. It has become a thing.

Therefore, if there are fewer interference noise components in the reception,
Although both inputs of the comparator 8 are in y agreement, when the interference noise component in the same signal increases, the output of the code discriminator 3 remains t't'r, but the code discriminator Since the output of the comparator 7 changes, both inputs of the comparator 8 become inconsistent, and thereby a code error prediction alarm signal can be obtained.

FIG. 2 is a block diagram of main parts showing another embodiment.
22, the carrier wave regenerated from the output side of the synchronous detector 21 by the carrier wave regenerator 23 is supplied to both transverse wave detectors 21 and 22, thereby obtaining the same result as in Fig. 1. In this case, , the expensive demodulator 2.12 is not required, and the configuration can be made at low cost.゛The delay adjuster 9 and the comparator 8 are
12 or the input side of the synchronous detectors 21 and 22. In this case, an analog type comparator may be used as the comparator 8.

Furthermore, the automatic waveform equalizer 11 is a prefix type.

Although any feedback type may be used, if it is a dead image, the delay time is small, and a delay line such as a cable may be used as the delay adjuster 9.

In addition, since signals for outputs 10 and above are generated pit by pit and at high speed, if a high-speed gate circuit or the like is used to switch the current line, line switching for outputs 10 and above will be possible without momentary interruption and before a code error occurs. Anything that can be done with signals can greatly improve the reliability of digital communications.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, interference noise is removed from the receiving signal No. 4 by an automatic waveform equalizer, and the delay time of this signal with respect to the receiving signal No. 4 is adjusted to separate both signals. By performing the comparison, it is possible to predict the occurrence of code errors based on interference noise, and there is no part that is difficult to adjust, resulting in a remarkable effect in predicting and detecting code errors in digital communication.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, FIG. 1 is a block diagram of the entire configuration, FIG. 2 is a block diagram of main parts showing another embodiment, and FIG. 3 is a block diagram of a conventional example. It is. 1...Input, 8...Comparator, 9...Delay adjuster, 11...Automatic waveform converter. Patent applicant: NEC Corporation agent Masaki Yamakawa (2 people from fG)

Claims (1)

[Claims] Interference noise is removed from the received signals through an automatic waveform equalizer, the delay time of the signal from which the interference noise has been removed is adjusted with respect to the received signals, and the two signals are compared, and the code is determined based on the comparison result. A code error prediction and detection method for digital communication characterized by obtaining an error prediction warning signal.