JPS5955663A - Detecting circuit of pulse trio - Google Patents

Abstract

PURPOSE:To detect an appropriate pulse trio with a simple circuit, by providing the circuit with a decoder circuit detecting that the counted value of a counter is ''2'' and a gate circuit detecting that the number of input pulses between violation pulses is ''2''. CONSTITUTION:When a trio string is inputted, the counted value of the counter 12 is ''2'' at the generation of violation error pulses. Namely, the number of unipolar pulses between violation error pulses is ''2''. When the counted value of the counter 12 is ''2'', outputs QA, QC, QD are turned to ''0'' and only an output QB is ''1''. Consequently, the output (d) of an AND gate 14 is turned to the high level and the output (e) of an AND gate 15 to which the output (d) and the output (b) of a violation error detector 11 are inputted is turned to ''1'', the high level, so that the pulse trio is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a pulse trio detection circuit, and particularly to a pulse trio detection circuit that is included in a test noise signal used for monitoring the speech quality of a repeater in a digital communication system, etc. The present invention relates to a circuit for digitally detecting a pulse trio signal.

(2) Background of the technology Generally, in a communication system that transmits signals by bipolar/4' pulse, testing of each repeater and transmission line or locating the fault location is performed by applying a test pulse to the repeater or transmission line under test. This is done by inputting As this test pulse signal, a pattern signal is used in which a so-called pulse trio consisting of a pair of double-current pulses and one single-current pulse is repeated for every predetermined bit. Therefore, it is necessary to detect a pattern signal containing this pulse trio on the output side of the repeater under test or the transmission line, but how this detection is performed depends on the configuration and cost of the test equipment such as the repeater. therefore, appropriate detection methods are required.

(3) Prior art and problems Conventionally, pulse trio detection when testing repeaters, etc. utilizes the fact that low frequency components change depending on the density of pulse trios included in the test pattern signal.
This low frequency component was detected by a band pass filter of a predetermined band.

However, the conventional type requires a pulse trio tester with band-pass filters for various bands and frequencies, resulting in a complex configuration of the tester, resulting in high costs and a national problem in implementing ICs. There was an inconvenience.

(4) Object of the Invention In view of the problems with the conventional type described above, an object of the present invention is to detect that a violation of an input bipolar pulse occurs every two input pulses in a Nockles Trio detection circuit. Based on this concept, it is an object of the present invention to enable a pulse trio to be properly detected using a simple circuit, and to easily integrate the detection circuit into an integrated circuit.

According to the present invention, the present invention provides a bipolar-unipolar conversion circuit for converting an input bipolar signal into a unipolar signal, a bipolar violation detection circuit for detecting bipolar violation of the input bipolar signal, and a bipolar-unipolar conversion circuit for detecting bipolar violation of the input bipolar signal. a counter that counts the output pulses of and is reset by the output of the violation detection circuit, a decoder circuit that detects that the count value of the counter is 2, and an output of the decoder circuit and an output of the violation detection circuit. This is achieved by providing a pulse trio detection circuit characterized in that it includes a dart circuit that detects that the number of input pulses between violation pulses is two.

(6) Embodiments of the Invention The present invention will be described in detail below with reference to the drawings. FIG. 1 partially shows the configuration of a digital communication system that is tested using a pulse trio detection circuit according to an embodiment of the present invention. In the system shown in the figure, there is a terminal section 3 including a terminal circuit 1 and a terminal repeater 2, intermediate repeaters 4 and 5, etc., and another terminal including a terminal circuit 1' and a terminal repeater 2'. Station equipment 3' etc. are connected via relay lines 6 and 7.

In the system shown in FIG. 1, the terminal circuit 1 of the terminal device 3
A signal is inputted from a terminal (not shown), etc., and the signal is converted into a bipolar signal in the terminal circuit 1 and sent to the relay line 6 via the transmission amplifier 2-1 of the terminal repeater 2. The signal sent to the relay line 6 is relayed via amplifiers 4-1 and 5-1 such as intermediate repeaters 4 and 5, and is received by another terminal device 3'. The signal received by the terminal device 3' is amplified and shaped by the receiving amplifier 2'-1 of the terminal repeater 2' and sent to a terminal (not shown) via the terminal circuit 1'. The signal input to the terminal circuit 1' of the terminal device 3' is similarly received at the terminal station &t3 via the terminal station repeater 2' relay line 7, intermediate repeaters 4 and 5, etc. The received signal is amplified and shaped by the receiving amplifier 2-2 of the receiver 2, inputted to the terminal station circuit 1, and transmitted to another terminal.

In the communication system as described above, when determining the margin of error of the intermediate repeaters 4 and 5, etc., for example, a pulse trio PT as shown in FIG. The test is performed by sending out a test pulse signal containing Here, the pulse trio means a three-pit continuous nozzle PT consisting of a pair of double-current pulses and one single-current pulse, as shown in FIG. 2(,). As the test noise signal, a pattern in which this pulse trio PT is repeated every n bits is used, with the polarity inverted at a low frequency (audio frequency) as shown in FIG. 2(b).

Conventionally, the test pulse signal as described above does not satisfy the bipolar side and has a DC component within the period of polarity reversal.
Therefore, from a long-term perspective, each repeater etc. has been tested using points that have low frequency components. That is, by inputting a test pulse signal as shown in FIG. 2(b) to the intermediate repeater under test, and inputting the output of the intermediate repeater to a bandpass filter of a predetermined band, the low Frequency components were detected, and repeaters and the like were tested by detecting the presence, density, and polarity of pulse trios based on the period and level of these low frequency components. However, as mentioned above, this conventional method has the disadvantages that the test equipment becomes complicated and it is difficult to integrate it into an IC.

The IJO detection circuit according to one embodiment of the present invention digitally detects the presence or absence of a Sibarst trio, which is different from the conventional method, and the circuit is shown in FIG. The 79 Lustrio detection circuit shown in FIG.
It is composed of AND gates 14, 15, other counters 16, inverters 17, 18, 19, and the like.

FIG. 4 shows waveforms of various parts in the circuit of FIG. 3. Hereinafter, the operation of the circuit of FIG. 3 will be explained with reference to FIG. For example, the bipolar-unipolar converter circuit 10 shown in FIG. Output. Further, when the X input bipolar pulse is a pulse of negative polarity, a pulse of positive polarity is output to the -NRZ output terminal. The pulses from both of these output terminals are input to the bipolar bioreciprocal detection circuit 11 and output from the same output terminal.
For example, if 2 or more bits of pulses are input consecutively from the +NRZ output terminal, a 4-bit error pulse is output. Therefore, if two or more pulses of the same polarity are input in succession in the i4 pulse signal input to the normal polarity/unipolar conversion circuit 10, a violation detection circuit 11 outputs a violation error signal. Output Sarel. This violation error signal can be outputted at the timing of the preceding mother signal among nine consecutive signals of the same polarity, as shown in FIG. It is also possible to output the signal at the time of the later pulse of the f pulse. The timing differs depending on the configuration of the hippo violation detection circuit 11 at which the violation error pulse is output. On the other hand, bipolar
+NRZ output terminal and -N of unipolar conversion circuit 10
The signal at the RZ output terminal is applied to the output terminal C of the ordart 13, and a unipolar pulse as shown in FIG. be done. The counter 12 counts the input unipolar 4 pulses,
An output of each digit is generated at each output terminal QA to QD. Further, an error pulse from the biolage date error detector 11 is applied to the clear terminal CLR of the counter 12,
The count value of the counter 12 is cleared to 0 by this error pulse. Therefore, assuming that the counting and clearing operations in the counter 12 are performed at the falling edge of the input signal and the clearing signal, respectively, FIG.
), if a pulse trio train as shown in ) is input,
The count value of the counter 12 becomes 2 at the time when the biolage error pulse is generated. Immediately, the number of unipolar pulses between the biorage and the error noculus is 2.
becomes. When the count value of the counter 12 becomes 2,
Outputs QA and QcIQD are both "0", that is, low level, and only output QB is Itl#, that is, high level. Therefore, the output d of ANDR-) 14 is at a high level, and the output e of ANDR-) 15, to which this output d and the output of the biorage error detector 11 are input, is "l", that is, a high level. Gino's Mother Rustrio is detected. The counter 16 generates, for example, a high level output when a predetermined number of the output e of the AND gate 15, that is, the detection pulse is input within a predetermined time, and the pulse trio is output due to an error in the transmission line. This deals with cases where the judgment is made incorrectly.

(7) Effects of the Invention As described above, according to the present invention, since the pulse trio is detected digitally, it is possible to easily integrate the pulse trio detection circuit into an integrated circuit, and it is also possible to integrate the pulse trio detection circuit into an integrated circuit. Thus, by using bandpass filters and the like, it is possible to reduce the cost of the repeater test equipment, and it is also possible to accurately detect pulse trios.

[Brief explanation of the drawing]

FIG. 1 shows A?A according to one embodiment of the present invention. A block circuit diagram showing the configuration of a digital communication system in which a transmission line, etc. is tested using a pulse trio detection circuit, Figure 2 is a schematic waveform diagram showing the configuration of a test signal including a pulse trio, and Figure 3 is a , a block circuit diagram showing a pulse trio detection circuit according to an embodiment of the present invention, and FIG. 4 is a waveform diagram for explaining the operation of the circuit of FIG. 3. 1.1'...Terminal station circuit, 2.2'...Terminal station repeater,
2-1, 2'-1, 2-2, 2'-2... amplifier,
3゜3'... End part, 4, 5... Intermediate repeater, 4-
1゜4-2.5-1.5-2...Amplifier, 6,7...
・Relay line, 10... Bipolar/unipolar converter, 11... Bipolar biolage eye detector, 12
...Counter\ 13...or dirt, 14.15
...and dart, 16...counter. Patent applicant Fujitsu Limited Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney 1) Yukio Patent attorney Akira Yamaguchi

Claims (1)

[Claims] a bipolar-unipolar conversion circuit that converts an input bipolar signal into a unipolar signal; a violation detection circuit that detects a bipolar violation of the input bipolar signal; and a violation detection circuit that counts the output pulses of the bipolar-unipolar conversion circuit, and a counter that is reset by the output of the violation detection circuit; a decoder circuit that detects that the count value of the counter is "2"; and a pie breaker connected to the output of the decoder circuit and the output of the violation detection circuit. 1. A loop detection circuit characterized by comprising a dirt circuit that detects that the number of input pulses between vr and arm is "2".