JPS63209358A - Method for testing coder and decoder - Google Patents

Abstract

PURPOSE:To reduce the test time by testing single a coding function and a decoding function of a coder/decoder mounted in a subscriber circuit. CONSTITUTION:The coder/decoder 4 mounted onto a subscriber circuit 1 connects a general-purpose test equipment 10 and an accessory circuit 400 by a probe pin P, a frequency signal a0 in voice band from a test signal generating circuit 200 is inputted to the test object coder/decoder 4, the coded output signal d1 is decoded by a testing coder/decoder 100, compares it with an original signal a0 to test the coding function of the test object coder/decoder 4. A test signal a0 outputted from the generating circuit 200 is inputted to the coder/ decoder 100, the coded signal d2 is inputted to the coder/decoder 4, the decoded output signal a2 is compared with the original signal a0 to test the decoding function.

Description

[Detailed Description of the Invention] [Summary] A code decoder and a general-purpose test device that are implemented in a subscriber circuit by adding a test code decoder, a test signal generation circuit, and a synchronization signal generation circuit to a general-purpose test device. and each additional circuit through a probe bin, input the voice band in-frequency test signal from the test signal generation circuit to the code decoder under test,
The encoded output signal is decoded by a test code decoder and compared with the original signal, and the signal obtained by encoding the voice band in-frequency test signal from the test signal generation circuit by the test code decoder is used as the test target code. By inputting the decoder and comparing the decoded output signal with the original signal, the testing time of the encoding and decoding functions of the code decoder is reduced.

[Industrial application field]

The present invention relates to a code decoder testing method that allows a code decoder installed in a subscriber circuit package for a digital exchange to be tested in a short time.

Digital exchanges have a current supply function, an overvoltage detection function, a calling signal sending function, a subscriber monitoring function, a two-wire four-wire conversion function, a test lead-in function, etc., as well as an analog-format audio signal arriving from the subscriber side. Each subscriber circuit is equipped with a code/decoding function that encodes a signal and sends it to the communication path side, and also decodes the encoded voice signal arriving from the communication path side and sends it to the subscriber side.

Therefore, there is a need for a method that can test this type of code/decoding function in a short time.

[Conventional technology]

FIG. 3 is a diagram showing an example of a subscriber circuit to be tested.

In FIG. 3, a current supply section (r3TF) 2 having a current supply function and a subscriber monitoring function (Ah), a ringing signal sending section (RG) 3 having a calling signal sending function and a subscriber monitoring function, a code decoding A code decoder (GO
DEC) 4, 2-line 4-wire converter (HYB) 5 equipped with a 2-line 4-wire conversion function, test lead-in part (HYB) equipped with a test lead-in function (
TST) 6, a control unit (C
NT) 7.

In the subscriber circuit 1, a plurality of circuits are mounted in the same cage.

Conventionally, this type of functional test of the code/decoder (CODEC) 4 has been performed as part of the functional test of the subscriber circuit 1 as a whole.

[Problem that the invention seeks to solve]

As is clear from the above explanation, in the conventional code/decoder testing method, the functional test of the code/decoder (CODEC) 4 is performed as part of the functional test of the subscriber circuit in general, which requires a large amount of testing time. There was a problem that required .

[Means for solving problems]

FIG. 1 is a diagram showing the principle of the present invention.

In FIG. 1, 1 is a subscriber circuit to be tested, and 4 is a code decoder to be tested 4.1 installed in the subscriber circuit 1.
0 is a general-purpose test device such as an in-circuit tester.

100 is a test code decoder having the same format as the code decoder 4 to be tested.

200 is a test signal generation circuit that generates an audio band internal frequency test signal aO.

300 is a synchronization signal generation circuit that generates a synchronization signal necessary for the operation of the code decoder 4 under test and the code decoder 100 for test.

Reference numeral 400 denotes an additional circuit that includes a test code decoder 100, a test signal generation circuit 200, and a synchronization signal generation circuit 300, and is installed alongside the general-purpose test apparatus 10.

When performing a test, the test target code decoder 4 mounted in the subscriber circuit 1, the additional circuit 400, and the general-purpose test device 10 are coupled by probe pins P.

[Effect]

First, the audio band in-frequency test signal aO output from the test signal generation circuit 2,00 in the additional circuit 400 is inputted from the analog input terminal of the code decoder 4 to be tested connected via the probe pin P, and the test is performed. The encoded signal d1 output from the digital output terminal of the target code decoder 4 is
The analog signal a1 input to the digital input terminal of the test code decoder 100 in the additional circuit 400 connected via the probe pin P and output from the analog output terminal of the test code decoder 100 is sent to the general-purpose test equipment 10. received at
By comparing with the audio band in-frequency test signal aO outputted by the test signal generation circuit 200, the test target code decoder 4
Test the normality of the encoding function.

Next, the audio band frequency test signal aO output from the test signal generation circuit 200 in the additional circuit 400 is inputted from the analog input terminal of the test code decoder 100 and output from the digital output terminal of the test code decoder 100. input the encoded signal d2 to the digital input terminal of the code decoder under test 4 connected via the probe pin P,
The analog signal a2 output from the analog output terminal of the code decoder 4 under test is received by the general-purpose test device 10 connected via the probe pin P, and the test signal generation circuit 20
The decoding function of the code decoder 4 to be tested is tested by comparing it with the audio band in-frequency test signal aO output by the test target code decoder 4.

As described above, the function test of the code decoder 4 to be tested installed in the subscriber circuit 1 can be performed independently, and the time required for the test can be significantly reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram illustrating a code decoder testing method according to an embodiment of the present invention. Note that the same reference numerals indicate the same objects throughout the figures.

In FIG. 2, the subscriber circuit 1 to be tested includes:
Only the code/decoder (CODEC) 4 to be tested is shown.

The test equipment that executes the functional test of the code/decoder (CODEC) 4 includes a general-purpose test equipment 10 capable of measuring analog signals such as an in-circuit tester, a test code decoder (CODEC) 21, and an audio signal. A dedicated additional circuit 20 containing a generation circuit 22 and a clock generation circuit 23 is also provided.

The test code/decoder (CODEC) 21 is a code/decoder of the same type and has the same characteristics as the code/decoder (CODEC) 4 to be tested, and the normality of its functions and characteristics has been confirmed. be.

The audio signal generation circuit 22 generates a test audio signal aO having a specific frequency within the audio band.

The clock generation circuit 23 is a code decoder (
CODEC) 4, and a test code decoder (CODEC
) 21 generates a lock signal or synchronization signal as necessary for operation.

When performing a test, it is mounted on a fixture or the like connected to the code decoder 0 to be tested.

As a result, the analog input terminal AI, analog output terminal AO, digital input terminal DI, and digital output terminal DO of the code/decoder (CODEC) 4 are connected to the output terminal of the audio signal generation circuit 22 and the signal reception terminal of the general-purpose test equipment 10, respectively. The digital output terminal DO and digital input terminal DI of the test code decoder (CODEC) 21 are
They are connected via probe pins P, respectively. Further, the clock signal and synchronization signal receiving terminals of the code decoder (CODEC) 4 are connected to the clock signal output terminal and the synchronization signal output terminal of the clock generation circuit 23 via probe pins P, respectively.

In this state, the test audio signal aO output from the audio signal generation circuit 22 is input to the analog input terminal AI of the code/decoder (CODEC) 4.

A code/decoder (CODEC) 4 uses an encoding function to encode the input test audio signal aO, and generates an encoded signal dl.
It is converted into and output from the digital output terminal DO.

The coded signal d1 is sent to a test code decoder (CO, DEC)
It is manually input to the digital input terminal DI of 21.

The test code decoder (CODEC) 21 decodes the input coded signal d1 and generates a decoded signal a in analog format.
1, output from the analog output terminal A○, and transmit it to the general-purpose test equipment IO.

The general-purpose test device 10 is a test code decoder (C0DEC)
The decoded signal a1 transmitted from the audio signal ordering circuit 22 is compared with the test audio signal aQ output from the audio signal ordering circuit 22, and if the error is within the allowable range, the encoding function of the code/decoder (CODEC) 4 is normalized. It is determined that

Next, the test audio signal aO output from the audio signal generation circuit 22 is input to the analog input terminal AI of the test code decoder (CODEC) 21.

The test code/decoder (CODEC) 21 encodes the input test audio signal aO, converts it into an encoded signal d2, and outputs the encoded signal d2 from the digital output terminal Do.

The encoded signal d2 is input to a digital input terminal DI of a code/decoder (CODEC) 4.

The code/decoder (CODEC) 4 uses a decoding function to decode the input coded signal d2, convert it to an analog format decoded signal a2, output it from the analog output terminal AO, and transmit it to the general-purpose test equipment 10. do.

The general-purpose test device 10 converts the decoded signal a2 transmitted from the code decoder (CODEC) 4 into the audio-signal generation circuit 22.
If the error is within the allowable range, the decoding function of the code/decoder (CODEC) 4 is determined to be normal.

As is clear from the above description, according to this embodiment, the code decoder (CODEC) 4 installed in the subscriber circuit 1
In order to independently test the encoding and decoding functions of
The time required for testing can be significantly reduced.

〔Effect of the invention〕

As described above, according to the present invention, the function test of the code/decoder installed in the subscriber circuit of a digital exchange can be performed independently, and the time required for the test can be significantly shortened.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing a code/decoder testing method according to an embodiment of the present invention, and FIG. 3 is a diagram showing an example of a subscriber circuit to be tested. be.

Claims (1)

[Scope of Claims] A test code decoder (100) having the same format as the code decoder (4) to be tested; a test signal generation circuit (200) that generates an audio band test signal (a0); An additional circuit (400) comprising a synchronization signal generation circuit (300) that generates a synchronization signal for operation of the code decoder under test (4) and the code decoder for test (100) is added to the general-purpose test equipment (10). The code decoder under test (4) added and mounted in the subscriber circuit (1) is coupled to the additional circuit (400) and the general-purpose test device (10) by a probe pin (P), The voice band in-frequency test signal (a0) output from the test signal generation circuit (200) is inputted from the analog input terminal of the code decoder under test (4), and the code decoder under test (4) is The encoded signal (d1) output from the digital output terminal is sent to the test code decoder (10
0) and receives an analog signal (a1) output from the analog output terminal of the test code decoder (100) by the general-purpose test device (10),
The encoding function of the code decoder (4) to be tested is tested by comparing it with the voice band in-frequency test signal (a0), and the voice band in-frequency test signal output from the test signal generation circuit (200) is tested. The signal (a0) is input from the analog input terminal of the test code decoder (100), and the encoded signal (d2) output from the digital output terminal of the test code decoder (100) is input to the test code decoder (100). receiving an analog signal (a2) input to a digital input terminal of a target code decoder (4) and output from an analog output terminal of the test target code decoder (4) by the general-purpose testing device (10);
A code/decoder testing method, characterized in that the decoding function of the code/decoder to be tested (4) is tested by comparing it with the audio band in-frequency test signal (a0).