JPS6087549A - Detector of quality of transmission line - Google Patents

Abstract

PURPOSE:To detect distortion of a signal with good accuracy without increasing the frequency of a transmission signal by sampling a reception waveform subjected to distortion through a transmission line and a reference waveform themselves. CONSTITUTION:A reception signal (b) subjected to distortion through the transmission line is inputted to a sampling circuit 14A, where the signal is sampled by a sampling clock signal (f) and a reception wave sampling signal (g) is outputted. Moreover, a reference signal (d) subjected to synchronous regeneration from reception signal is inputted to a sampling circuit 14B, where the signal is sampled by the signal (f) and a reception wave sampling signal (h) is outputted. A subtraction circuit 15 subtracts the signal (h) from the signal (g) at each sampling period and outputs a difference sampling value (i) is outputted. The sampling values (i) exceeding a prescribed level are outputted as an amplitude distortion signal l at a threshold level detector 16A and when the signal is prescribed value or over, a preset 2-stage counter circuit 20C outputs an amplitude distortion error signal (r). Furthermore, two-stage counter circuits 20A, 20B output a waveform error signal (p) and a phase distortion error signal (q).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission path quality detection device that continuously detects the quality of a transmission path.
Quantitatively detects the quality of the transmission line by measuring sampling errors and node errors of sine wave signals, as well as amplitude distortion and biphasic distortion that can be detected secondary to sampling error detection, with high precision and detail. The present invention relates to a transmission path quality detection device.

Conventionally, various transmission path quality detection devices have already been proposed. The structure of a conventional method particularly related to the present invention is shown in FIG. 1, and the operation thereof is shown in a signal waveform diagram of each signal in FIG. 2 to explain this method.

When the signal a output from the sine wave oscillator l passes through the transmission line 2, it is distorted by noise and the received signal or waveform shaping circuit 3
The waveform shaped signal C rises and falls at the + side slice level and -(111 slice level, respectively).
is output and input to the exclusive OR circuit 4. Further, the rectangular wave generator 5 generates a reference waveform signal d having the same frequency as the signal a whose phase is synchronized with the signal C. Signal f synchronized with signal d
is input to the clock supply circuit 7, and the frequency of the signal 1;a is multiplied by N times to generate a sample clock signal 4g. The exclusive OR circuit 4 takes the exclusive OR of the signal C and the signal d and outputs a signal 4JO. In the AND circuit 6,
Performs the logical product of signal C and signal g to generate element error signal 1
Outputs 1. The reset control circuit 9 outputs a reset signal i to the precent counting circuit 8 according to a predetermined detection time using the signal g. The signal + is counted by a preset counting circuit 8 and outputs a quality standard deterioration signal j when the preset value is exceeded.

Conventional transmission line quality detection devices have a relatively simple circuit configuration as described above, but the rising and falling points at the slice level of the received signal are the same as the rising and falling points of the reference waveform. When the timing is right with the point, distortion of the received signal due to same polarity noise after exceeding the + side slice level or - side slice level will not be detected, and distortion due to different polarity noise will also be at the one side slice level. Otherwise, it will not be detected unless it exceeds the + side slice level. For example, as shown in points @, ■, ■, ■ in Figure 3, the rising point of the waveform shaping signal at the + side slice level, the falling point of the - side slice level, and the falling point of the - side slice level. , the received signal distortion between the rising points of the + side slice level has the disadvantage that it is rarely detected, and in order to improve the detection accuracy in the conventional method, the frequency of the transmitted signal must be increased. This has the disadvantage that a wide band must be used to detect the quality of the transmission path.

The present invention can accurately detect signal distortion without increasing the frequency of the transmitted signal, and can identify the cause of distortion by identifying the distortion of one signal as amplitude distortion 9 phase distortion. The present invention provides a transmission line quality detection device that can represent and detect the quality of other lines on a multiplexed transmission line by detecting the quality of a specific line on that transmission line.

In the present invention, a sine wave signal is sent to the transmission path to extract pure distortion components from a signal superimposed with noise that enters the transmission path, and quantitatively detect this as the quality of the transmission path. The received signal is sampled as it is and is reproduced from the received wave sampled signal and the received signal.

A synchronized reference signal is generated and sampled, and the reference wave sampling signal is compared at each sampling period, and the distortion component is extracted as a differential sample value C. By slicing this at an arbitrary slice level, amplitude distortion can be calculated. When each number is 01 as biphasic distortion and exceeds a certain number, it is detected as an error. In addition, the quality of the transmission path is detected by calculating the logical sum of each error, counting the number of sampling bit errors to 41, and detecting the error as a waveform error in the received signal if the number exceeds a certain number.

The configuration of an embodiment of the transmission path quality detection device according to the present invention is shown in FIG. 4, and a signal waveform diagram of each signal showing its operation is shown in FIG. 5, and will be explained.

A sine wave signal a sent from a sine wave oscillator 1 that generates a sine wave with sufficiently stable amplitude and period is susceptible to the effects of various noises and occasional breaks in the static transmission line characteristics 1 when passing through the transmission line 2. Distorted reception. This distorted signal, the received signal, is input to an automatic phase control circuit IO having a certain time constant, and a phase control signal C is output. The phase synchronized oscillator 11 outputs a reference signal d having the same phase and constant amplitude as the received signal according to the phase control signal C. A frequency multiplier 12 converts the reference signal d into a signal e having a frequency that is an integral multiple of the reference signal d, and a rectangular wave generator 13 outputs a rectangular sampling clock signal f.

Received signal distorted in transmission path, sampling circuit 1
4A, is sampled at the 174th sampling period of the sampling clock signal f, and outputs a received wave sampled signal g. Also, synchronized from receiving (ii communication ~ J-).

The reproduced reference signal d is input to the sampling circuit 14B, where it is sampled at the sampling period of the sampling clock signal f, and a received wave sampling signal is output.

The subtraction circuit 15 subtracts the reference wave sampling signal from the received wave sampling signal every sampling period, and outputs a difference sample value i. The difference sample value i is output by a threshold level detector 168 as an amplitude distortion component signal l if it exceeds the sliceless residual level at a predetermined level.

The amplitude distortion component signal l is counted by a precent two-stage counting circuit 20C, and if it exceeds a predetermined number, it is determined that the received signal is in error due to amplitude distortion. Here, for a certain period of time, the sampling clock signal
Reset signal 6. It depends on the period in which o appears. The following fixed time is based on this.

On the other hand, the received wave sampling signal is detected by the threshold level detector 1 due to the threshold level and small detection W 16C.
Slices are made at a level lower than the threshold level of 6A, and a received wave phase element signal k is output for those exceeding the threshold level. Further, the reference wave sampling signal is sliced by the threshold level detector 16B at the same level as the threshold level detector 16C, and a reference wave phase element signal j is output for those exceeding the threshold level. The exclusive OR circuit 17 performs an exclusive OR operation on the received wave phase element signal j and the reference wave phase element signal at the same period as the sampling clock signal f, and outputs the result as a phase distortion component signal m. The phase distortion component signal m is counted by a preset two-stage counting circuit 20B, and if it exceeds a certain number, it is determined that an error is due to phase distortion of the received signal, and after counting for a certain period of time, an amplitude correct error signal q is output.

Next, the OR circuit 18 performs the logical sum of the amplitude distortion component signal l and the phase distortion component signal m, and outputs a waveform distortion component signal n. The waveform distortion component signal n is counted by a preset two-stage n1 counting circuit 20A, and if it is greater than a certain number, it is determined that the error is due to waveform distortion of the received signal, and the waveform error component signal n is multiplied for a certain period of time, and a waveform error Gj "jp is output.

As in the above embodiments, according to the present invention, the received waveform distorted in the transmission path and the reference waveform themselves are sampled. Many distortion components can be masked by shaping the
However, since it depends on the sampling period and not on the frequency of the transmitted signal, if the transmitting wave number is the same between this embodiment and the conventional device, the former has higher reliability and 1"11 accuracy. It has the advantage of being detectable.

Furthermore, in this embodiment, in the process of detecting the quality of transmission 1-δ as a waveform error, it is possible to output the amplitude correct error and the phase correct error by It'll L, respectively, so the quality of the transmission path can be Therefore, it is possible to detect ii'('tllll).

[Brief explanation of drawings]

Figure 1 shows a conventional transmission line product! A configuration diagram of a JfL detection device. FIG. 2 is a signal waveform diagram of a conventional transmission path quality detection device. FIG. 3 is a diagram showing problems with a conventional device, and FIG. 4 is a configuration diagram of a transmission path quality detection device according to an embodiment of the present invention. FIG. 5 shows transmission line node 5! of an embodiment of the present invention. ! FIG. 3 is a signal waveform diagram of the IX detection device. In the figure, l - sine wave oscillator, 2 - transmission line, 3 - waveform shaping circuit, 4 - exclusive OR circuit, 5 - square wave generator, 6 - i
i19i product circuit, 7-clock connection circuit. 8-preset counting circuit, 9-reset control circuit. 10- automatic phase control circuit, 11- phase synchronized oscillator. 12-frequency multiplier circuit, 1.3- intelligent wave generator, 14A
, 1413, 14C-sampling circuit, 15-subtraction circuit, 1
6A, 1.613, 16C-threshold torque detector, 17-exclusive OR circuit, 18-OR circuit, 19
-Reset 1lill i:tll, 208, 20B
, 20C-preset two-stage counting circuit. 2nd building 3rd floor Q) (Thursday - 9J Tuesday ・) Mi ni

Claims (1)

[Claims] means for transmitting a sine wave signal with stable amplitude and period to a transmission line; means for receiving the sine wave signal via the transmission line; and means for sampling the received signal at a frequency higher than the signal frequency to generate a received wave means for generating a sampling signal; means for generating a reference signal phase-synchronized with the received signal;
The reference signal is the same as the sampling frequency of the received signal □−
means for sampling at a frequency and generating a reference wave sampling signal, means for subtracting the received wave sampling signal from the reference wave sampling signal at each sampling period and extracting the difference, and slicing the difference at a predetermined level. 7 means for extracting amplitude distortion; means for counting amplitude distortion and outputting it as an error due to amplitude distortion of the received signal when the number exceeds a certain number; and means for counting and outputting errors due to amplitude distortion for a certain period of time. The phase distortion is extracted by slicing each of the reference wave sampling signal and the received wave sampling signal at a level lower than the above-mentioned slice level, and calculating the exclusive OR of the generated signals. means for counting the phase distortion and outputting it as an error due to the phase distortion of the received signal when it exceeds a certain number; means for counting the error due to the phase distortion for a certain period of time and resetting after outputting it; Means for calculating the logical sum of amplitude distortion and phase distortion, counting waveform distortion sampling bit errors, and outputting it as a waveform error of the received signal when the number exceeds a certain number, and resetting after counting and outputting the waveform error for a certain period of time. 1. A transmission line quality detection device comprising: means for detecting the quality of a transmission line.