JPH01147934A - Loopback test system for multiplex converter - Google Patents

Abstract

PURPOSE:To reduce the scale of the test side by selecting a test use low-order group unipolar signal, inserting it to a multiplex converter to be tested and applying branch so as to apply loopback test of the multiplex converter. CONSTITUTION:Plural selecting circuits 12 select either of a test use low-order group unipolar signal generated from a test signal generator 11 and plural low-order group unipolar signal converted by plural B/U conversion circuits 13 respectively and supply the result to a multiplexer circuit 14. The plural selecting circuits 12 select a test low-order group unipolar signal respectively during the test and supply the result to the multiplex circuit 14. The multiplex circuit 14 multiplexes the result to one group of high-order group unipolar signal, the result is converted into one group of high-order group bipolar signal at the U/B conversion circuit 15, the converted signal is sent to the outside of the multiplex converter 10 from an output terminal 16 and inputted to the input terminal 17 of the multiplex converter 10 for the loopback test again.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a folding test method in a multiplex conversion device that multiplex-converts a plurality of low-order group signals into a group of high-order group signals.

[Prior Art] A conventional foldback test method for a multiplex converter will be described with reference to FIG.

The test low-order group unipolar signals generated by the test signal generator 8 are converted from the test low-order group unipolar signals to low-order group bipolar signals in a plurality of unipolar/bipolar (U/B) conversion circuits 24, and multiplexed. The signals are respectively input to the input terminals 22 of the conversion device 10. The plurality of input low-order group bipolar signals are converted into a plurality of low-order group unipolar signals in a plurality of bipolar/unipolar (B/U) conversion circuits 13, and then converted into one group of high-order group unipolar signals in a multiplexing circuit 14. The signal is multiplexed into a unipolar signal, converted into a high-order group bipolar signal by the U/B conversion circuit 15, and sent out from the output terminal 16 of the multiplex conversion device 10.

For the foldback test, the high-order group bipolar signal inputted again from the input terminal 17 to the multiplex converter 10 is converted into a high-order group unipolar signal by the B/U conversion circuit 18, and into a plurality of low-order group unipolar signals by the separation circuit 19. separated. A plurality of separated low-order group unipolar signals are transmitted to a plurality of U/Bs.
Each signal is converted into a plurality of low-order group bipolar signals by the conversion circuit 20 and sent out from the output terminal 21 of the multiplex conversion device 10 . The plurality of low-order group bipolar signals sent out are each converted again into a plurality of low-order group unipolar signals by the plurality of B/U conversion circuits 25, and then sent to the error detection circuit 23. The error detection circuit 23 detects bit errors in the input signal.

[Problems to be Solved by the Invention] In the above-mentioned conventional foldback test method for multiplex converters,
Depending on the multiplicity (number of low-order group signals to be multiplexed) of the multiplex conversion device under test 10, a considerable number of U/B conversion circuits 24 and B/U conversion circuits 25 are required on the test device side. The system becomes large-scale and costs increase. Moreover, since the U/B conversion circuit 24 and B/U conversion circuit 25 on the test equipment side are analog circuits, the U/B conversion circuits 15 and 20 and the B/U conversion circuits 13 and 18 of the multiplex conversion device under test 10 are analog circuits. If it does not have better characteristics than the above, there is a drawback that it becomes unclear which U/B conversion circuit or B/U conversion circuit is being tested, the test equipment side or the multiplex converter under test 10 side. .

[Means for Solving the Problems] According to the present invention, a plurality of first input terminals into which a plurality of low-order group bipolar signals are input, and a plurality of low-order input terminals input from the plurality of first input terminals. a plurality of first bipolar/unipolar conversion means for converting each next-order group bipolar signal into a plurality of low-order group unipolar signals; and a plurality of low-order group unipolar signals converted by the plurality of first bipolar/unipolar conversion means. a first unipolar/bipolar conversion means that converts the group of high-order unipolar signals multiplexed by the multiplexing means into a group of high-order bipolar signals; , a first output terminal that outputs a group of high-order group bipolar signals converted by the first unipolar/bipolar conversion means;
a second input terminal for inputting a group of high-order group bipolar signals; and a second bipolar/unipolar conversion means for converting the group of high-order group bipolar signals input from the second input terminal into a group of high-order group unipolar signals. and separation means for separating a group of high-order group unipolar signals converted by the second bipolar/unipolar conversion means into a plurality of low-order group unipolar signals, and a plurality of low-order group unipolar signals separated by the separation means. a plurality of second unipolar/bipolar conversion means for converting each into a plurality of low-order group bipolar signals, and each outputs a plurality of low-order group bipolar signals converted by the plurality of second unipolar/bipolar conversion means. In a method for repeating testing a multiplex converter having a plurality of second output terminals, the first output terminal and the second input terminal are connected, and the plurality of second output terminals and the A test signal generation means that connects each of the plurality of first input terminals and generates a low-order group unipolar signal for testing, and is inserted between the plurality of first bipolar/unipolar conversion means and the multiplexing means. and selecting one of the plurality of low-order group unipolar signals converted by the plurality of first bipolar/unipolar conversion means and the test low-order group unipolar signal generated from the test signal generation means. A multiplex conversion device comprising a plurality of selection means and an error detection means for respectively detecting bit errors in a plurality of low-order group unipolar signals converted by the plurality of first bipolar/unipolar conversion means. A fold-back test method is obtained.

Further, according to the present invention, a plurality of first input terminals into which a plurality of low-order group bipolar signals are input, and a plurality of low-order group bipolar signals input from the plurality of first input terminals are respectively input to a plurality of first input terminals. a plurality of first converting signals into a low order group unipolar signal;
bipolar/unipolar conversion means, multiplexing means for multiplexing a plurality of low-order group unipolar signals converted by the plurality of first bipolar/unipolar conversion means into a group of high-order group unipolar signals, and the multiplexing means. 1 multiplexed with
a first unipolar/bipolar conversion means for converting a group of high-order group unipolar signals into a group of high-order group bipolar signals; and a first unipolar/bipolar conversion means for outputting a group of high-order group bipolar signals converted by the first unipolar/bipolar conversion means. an output terminal, a second input terminal for inputting a group of high-order group bipolar signals, and a second bipolar terminal for converting the group of high-order group bipolar signals input from the second input terminal into a group of high-order group unipolar signals. /unipolar conversion means, and the second
separation means for separating one group of high-order group unipolar signals converted by the bipolar/unipolar conversion means into a plurality of low-order group unipolar signals; a plurality of second unipolar/bipolar conversion means for converting into next-order group bipolar signals; and a plurality of second unipolar/bipolar conversion means for respectively outputting a plurality of low-order group bipolar signals converted by the plurality of second unipolar/bipolar conversion means. In a method for repeating testing a multiplex converter having output terminals, the first output terminal and the second input terminal are connected, and the plurality of second output terminals and the plurality of first A test signal generating means for generating a low-order group unipolar signal for testing by connecting the input terminals respectively, and a test signal generating means inserted between the separating means and the plurality of second unipolar/bipolar converting means, and the separating means a plurality of selection means for selecting one of the plurality of separated low-order group unipolar signals and the test low-order group unipolar signals generated from the test signal generation means; and a plurality of separated low-order group unipolar signals by the separation means. and error detection means for detecting bit errors in low-order group unipolar signals, respectively.

[Examples] Examples of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, the folding test method of the multiplex converter 10 according to the first embodiment of the present invention includes a test signal generator 11 that generates a low-order group unipolar signal for testing. The group unipolar signal is supplied to one input terminal of the plurality of selection circuits 12.

A plurality of low-order group unipolar signals converted by a plurality of B/U conversion circuits 13 are respectively supplied to the other input terminals of the plurality of selection circuits 12 . Choice of order i? 812 is
Each of the test low-order group unipolar signals generated from the test signal generator 11 and the plurality of low-order group unipolar signals converted by the plurality of B/U conversion circuits 13 is selected, and the plurality of selected The low-order group unipolar signal is sent to the multiplexing circuit 14.

During the test, the plurality of selection circuits 12 each select a test low-order group unipolar signal, and send these to the multiplexing circuit 14 as a plurality of selected low-order group unipolar signals. The multiplexing circuit 14 multiplexes the selected low-order group unipolar signals of these orders (a plurality of test low-order group unipolar signals) into a group of high-order group unipolar signals. The one group of high-order group unipolar signals multiplexed by the multiplexing circuit 14 is converted into one group of high-order group bipolar signals by the U/B conversion circuit 15, and this one group of high-order group bipolar signals is output from the output terminal 16 to the multiplex converter. 10 and inputted to the input terminal 17 of the multiplex converter 10 again for loopback testing. This input group of high-order group bipolar signals is
The B/U conversion circuit 18 converts the signal into a group of high-order group unipolar signals, and the separation circuit 19 separates this group of high-order group unipolar signals into a plurality of low-order group unipolar signals. The plurality of low-order group unipolar signals separated by the separation circuit 10 are respectively converted into a plurality of low-order group bipolar signals by the plurality of U/B conversion circuits 20. Multiple output terminals 21
is sent out from the multiplex converter 10, and the multiplex converter 10
After being turned back outside, the signals are again input to the plurality of input terminals 22 of the multiplex converter 10. The plurality of input low-order group bipolar signals are each converted into a plurality of low-order unipolar signals by the plurality of B/U conversion circuits 13, and then supplied to the error detection circuit 23, where bit errors are detected. be done.

It can be seen that the signal return test of the multiplex converter 10 can be performed using the above method.

Referring to FIG. 2, in the folding test method of the multiplex converter 10 according to the second embodiment of the present invention, the test low-order group unipolar signal generated from the test signal generator 11 is transmitted to the separation circuit 19 and a plurality of U The signal is supplied to one input terminal of a plurality of selection circuits 12 each inserted between the /B conversion circuits 20. Multiple selection times FI! The other input terminal of 112 is supplied with a plurality of low-order group unipolar signals divided by the separation circuit 19, respectively. The plurality of selection circuits 12 each select one of the test low-order group unipolar signal generated from the test signal generator 11 and the plurality of low-order group unipolar signals separated by the separation circuit 19, and The selected low-order group unipolar signals are each sent to a plurality of U/B conversion circuits 20.

During the test, the plurality of selection circuits 12 each select a test low-order group unipolar signal, and these are used as the plurality of selected low-order group unipolar signals to be sent to the plurality of U/B conversion circuits 20.
Send to. The plurality of U/B conversion circuits 20 each convert the plurality of selected low-order group unipolar signals (the plurality of test low-order group unipolar signals) into a plurality of low-order group bipolar signals. These plural low-order group bipolar signals are each sent out from the multiplex converter 10 from the multiple output terminals 21, and after being turned back outside the multiplex converter 10, are inputted again to the multiple input terminals 22 of the multiplex converter 10. be done. The plurality of input low-order group bipolar signals are respectively converted into a plurality of low-order group unipolar signals by the plurality of B/U conversion circuits 13 and then sent to the multiplexing circuit 14. The multiplexing circuit 14 multiplexes a plurality of low-order group unipolar signals into one group of high-order group unipolar signals. This multiplexing circuit 14
One group of high-order group unipolar signals multiplexed with U/B
The conversion circuit 15 converts the signals into a group of high-order group bipolar signals, and this group of high-order bipolar signals is sent out from the multiplex converter 10 from the output terminal 16, and is then sent to the input terminal 17 of the multiplex converter 10 for a repeat test. is input. The input one group of high-order group bipolar signals is converted into one group of high-order group unipolar signals by the B/U conversion circuit 18, and this one group of high-order group unipolar signals is converted into one group of high-order group unipolar signals by the separation circuit 19.
is separated into a plurality of low-order group unipolar signals. The plurality of low-order group unipolar signals separated by this separation circuit 10 are supplied to an error detection circuit 23, where bit errors are detected.

It can be seen that the signal return test of the multiplex converter 10 can be performed using the above method.

[Effects of the Invention] As is clear from the above description, according to the present invention, a selection circuit that selects a low-order group unipolar signal of the main line system and a low-order group unipolar signal for testing generated from the test signal generating means is provided. During the test, the test low-order group unipolar signal is selected by the selection circuit, inserted into the multiplex converter under test, branched, and looped back to the multiplex converter, thereby reducing the scale of the test side. It can be downsized, and since analog circuits are omitted, there is no need to consider the characteristics of that part.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a folding test method for a multiplex converter according to a first embodiment of the present invention, and FIG. 2 shows a structure of a foldback test method for a multiplex converter according to a second embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of a folding test method of a conventional multiplex converter. 10... Multiplex converter, 11... Test signal generator,
12... Selection circuit, 13... Bipolar/unipolar (B/U) conversion circuit, 14... Multiplexing circuit, 15
... Unipolar/bipolar (U/B) conversion circuit, 1
6... Output terminal, 17... Input terminal, 18... Bipolar/unipolar (B/U) conversion circuit, 19...
Separation circuit, 20...unipolar/bipolar (U/B
) conversion circuit, 21...output terminal, 22...input terminal, 23...error detection circuit.

Claims (1)

[Claims] 1) A plurality of first input signals receiving a plurality of low-order group bipolar signals;
a plurality of first bipolar/unipolar conversion means for converting a plurality of low-order group bipolar signals inputted from the plurality of first input terminals into a plurality of low-order group unipolar signals, respectively; multiplexing means for multiplexing a plurality of low-order group unipolar signals converted by the first bipolar/unipolar conversion means into a group of high-order group unipolar signals; and a group of high-order group unipolar signals multiplexed by the multiplexing means. a first unipolar/bipolar conversion means for converting a signal into a group of high-order group bipolar signals; a first output terminal for outputting a group of high-order group bipolar signals converted by the first unipolar/bipolar conversion means; a second input terminal for inputting one group of high-order group bipolar signals; and a second bipolar/unipolar conversion means for converting one group of high-order group bipolar signals inputted from the second input terminal into one group of high-order group unipolar signals. and separation means for separating a group of high-order group unipolar signals converted by the second bipolar/unipolar conversion means into a plurality of low-order group unipolar signals, and a plurality of low-order group unipolar signals separated by the separation means. a plurality of second unipolar/bipolar conversion means for converting each into a plurality of low-order group bipolar signals, and each outputs a plurality of low-order group bipolar signals converted by the plurality of second unipolar/bipolar conversion means. In a method for loop testing a multiplex converter having a plurality of second output terminals, the first output terminal and the second input terminal are connected, and the plurality of second output terminals and the A test signal generation means that connects each of the plurality of first input terminals and generates a low-order group unipolar signal for testing, and is inserted between the plurality of first bipolar/unipolar conversion means and the multiplexing means. and selecting either one of the plurality of low-order group unipolar signals converted by the plurality of first bipolar/unipolar conversion means and the test low-order group unipolar signal generated from the test signal generation means. A multiplex conversion device comprising: a plurality of selection means; and an error detection means for detecting bit errors in each of the plurality of low-order group unipolar signals converted by the plurality of first bipolar/unipolar conversion means. Folded test method. 2) A plurality of first input signals receiving a plurality of low-order group bipolar signals.
a plurality of first bipolar/unipolar conversion means for converting a plurality of low-order group bipolar signals inputted from the plurality of first input terminals into a plurality of low-order group unipolar signals, respectively; multiplexing means for multiplexing a plurality of low-order group unipolar signals converted by the first bipolar/unipolar conversion means into a group of high-order group unipolar signals; and a group of high-order group unipolar signals multiplexed by the multiplexing means. a first unipolar/bipolar conversion means for converting a signal into a group of high-order group bipolar signals; a first output terminal for outputting a group of high-order group bipolar signals converted by the first unipolar/bipolar conversion means; a second input terminal for inputting one group of high-order group bipolar signals; and a second bipolar/unipolar conversion means for converting one group of high-order group bipolar signals inputted from the second input terminal into one group of high-order group unipolar signals. and separation means for separating a group of high-order group unipolar signals converted by the second bipolar/unipolar conversion means into a plurality of low-order group unipolar signals, and a plurality of low-order group unipolar signals separated by the separation means. a plurality of second unipolar/bipolar conversion means for converting each into a plurality of low-order group bipolar signals, and each outputs a plurality of low-order group bipolar signals converted by the plurality of second unipolar/bipolar conversion means. In a method for loop testing a multiplex converter having a plurality of second output terminals, the first output terminal and the second input terminal are connected, and the plurality of second output terminals and the A test signal generation means that connects each of the plurality of first input terminals and generates a low-order group unipolar signal for testing, and is inserted between the separation means and the plurality of second unipolar/bipolar conversion means. , a plurality of selection means for respectively selecting one of the plurality of low-order group unipolar signals separated by the separation means and the test low-order group unipolar signal generated from the test signal generation means; and the separation means. and error detection means for respectively detecting bit errors in a plurality of low-order group unipolar signals separated by .