JPS6349950B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for automatically measuring the transmission characteristics of a communication network including a switch.

When there are a large number of trunk lines, there is a method that automatically measures the transmission characteristics (call loss, noise) of the trunk lines during quiet periods (for example, when reading magazines,
Facilities Vol.15 No.5, Vol.19 No.6, 10, 11). The present invention relates to an improvement of this method, in which a measuring device is installed at the first station, which is the center of the communication network, and a test trunk for relaying measurements is placed at a second station in the periphery, and transmission is performed using a loopback method. It performs automatic measurement of characteristics.

First, a known method will be briefly explained based on FIG.

In the figure, EX-A is a central first office exchange, and EX-B is one of the second exchanges located on the loop of EX-A. OGT1 and OGT2 in exchanges EX-A and EX-B are outgoing trunks, ICT1 and ICT
2 is an incoming trunk, SWF1 and SWF2 are switch frames of the exchange, and MKR1 and MKR2 are control devices of the exchange. Further, H in EX-B is a hybrid circuit that performs 4-wire/2-wire conversion. OTM1 and OTM2 in the transmission characteristic measuring section are transmission characteristic measuring devices on the sending side, TTM1 and TTM2 are transmission characteristic measuring devices on the receiving side, and PRT1 and PRT2 are printers for printing the test results. in the control section
OTT1 and OTT2 are calling side test trunks, TTT
1, TTT2 is the called side test trunk, CONN1,
CONN2 is a connecting device, and TLR1 and TLR2 are translators that extract information necessary for testing.

The originating test trunk OTT1 is a translator
The connection device CONN1 receives the information extracted sequentially from TLR1 including the test line number and line transmission standard.
The specified outgoing trunk OGT1 is captured by operating the control device MKR1 via the control device MKR1.
The originating test trunk OTT1 is the outgoing trunk OGT1
Activates the incoming trunk ICT2 via the
to capture. The terminating side test trunk TTT2 acquires the terminating side transmission characteristic measuring device TTT2. here,
OTM1-OTT1-SWF1-OGT1-H-ICT
2-SWF2-TTT2-TTM2 connection path is completed, and transmission characteristics such as call loss and noise are measured.

Figure 2 shows the measurement principle diagram of transmission characteristics, and shows the OSC
is an oscillator, LM is a level meter, and NM is a noise voltage measuring device, all of which have the function of automatically measuring call loss and the integral value of noise voltage, and displaying the results as electrical signals. MOD is a modem, BPF is a band filter, and AMP is an amplifier. OTM1 indicates a transmission characteristic measuring device on the transmitting side, and TTM2 indicates a transmitting characteristic measuring device on the receiving side. R is the resistance of the reference impedance.

In this example, the exchanger EX-A is a 4-wire type, and the exchanger EX-B
exemplifies the case of a two-wire system, but both cases are the same for either a four-wire system or a two-wire system.

In Figure 2a, the transmission characteristics measuring device on the receiving side
The TTM2 oscillator OSC sends out a 1KHz reference level signal, which is then measured by the transmission characteristics measuring device on the transmitting side.
Measured with level meter LM of OTM1, TTM2
Measure the loss between OTM1 and OTM1. Figure 2b is
Terminate TTM2 with reference impedance R, and use a noise voltage measuring device in the transmission characteristic measuring device OTM1 on the transmitting side.
Measure the noise voltage with NM.

The call loss from OTM1 to TTM2 uses a method called the loopback method, as shown in Figure 2c.
Sends a 0.8KHz signal from the oscillator OSC1,
The output of the 1.8KHz oscillator OSC2 is modulated by the modulator/demodulator MOD in the transmission characteristic measuring device TTM2 on the receiving side, and the 1.0KHz modulated wave is taken out through the band filter BPF, amplified by the amplifier AMP, and transmitted on the sending side. The signal is sent to the level meter LM of the characteristic measuring device OTM1, and the transmission level is automatically measured. From this, the transmission loss on the return path is determined by subtracting the transmission loss on the outbound path obtained in the measurement shown in FIG. 2a.

Figure 2 d shows a noise voltage measurement circuit from the transmission characteristic measuring device OTM1 on the transmitting side to the transmission characteristic measuring device TTM2 on the terminating side, and the measurement results are transferred from the transmission characteristic measuring device TTM2 on the terminating side to the transmission characteristic measuring device OTM on the transmitting side.
1 with a 1000Hz pulse signal and send it to the printer.
Printed on PRT1.

In this method, the called side transmission characteristic measuring device TTM
2. Loopback modem MOD, bandpass filter BPF, amplifier AMP, and noise voltage measuring device
It is necessary to provide an NM at each opposing station, and if there are many opposing stations, the price of the measuring device will increase.

In addition, in Figure 1, from exchange EX-B to exchange
line to EX-A (i.e., outgoing trunk
In order to measure the transmission characteristics of the line (from OGT2 to incoming trunk ICT1), on the exchange EX-B side,
A calling side transmission characteristic measuring device OTM2, a calling side test trunk OTT2, and a connecting device CONN2 are required, and an incoming test trunk is also required on the exchange EX-A side.
TT1 and the called side transmission characteristic measuring device TTM1 are required. Therefore, even more investment is required for measuring the transmission characteristics.

The present invention aims to eliminate the drawbacks of such conventional methods, simplify each measuring device, and provide an automatic transmission characteristic measurement method having equivalent functions, and will be described in detail below with reference to the drawings.

FIG. 3 is a diagram of a relay system to which the present invention is applied.
In the figure, EX-A is the central exchange at the first station, and EX-B is one of the exchanges at the second station around EX-A. Outgoing trunk OGT1, OGT2, incoming trunk ICT1, ICT
2. The switch frames SWF1 and SWF2, the control devices MKR1 and MKR2, and the hybrid circuit H are the same as those shown in FIG. The TM in the transmission characteristic measurement section is the transmission characteristic measurement device, and the OTT in the control section
is the calling side test trunk, TTT is the called side test trunk, RTT is the relay test trunk, CONN1,
CONN2 is a connecting device. TLR is a translator that extracts the information necessary for testing, and PRT is a printer that prints out test results.

In Fig. 3, the test trunk OTT on the originating side receives the test line number and line transmission characteristic standards sequentially extracted from the translator TLR, and connects the specified outgoing trunk OGT1 to the connecting device CONN1.
Capture via. The originating test trunk OTT activates the incoming trunk ICT2 via the outgoing trunk OGT1, controls the terminating exchange EX-B, and captures the relay test trunk RTT. The originating test trunk OTT further sends outgoing trunk OGT2 to the relay test trunk RTT based on the information extracted from the TLR.
The relay test trunk RTT sends the specified number of the relay test trunk RTT to the specified outgoing trunk via the connecting device CONN2.
Select OGT2. The relay test trunk RTT is the connection device CONN2, the outgoing trunk OGT2, and the incoming trunk.
A signal is sent to the exchange EX-A via ICT1, and the called side test trunk TTT is captured. As a result,
This means that the OTT-RTT-TTT connection is completed. Here, the first line between OTT and RTT,
The transmission characteristics of the second line between RTT and TTT will be measured. The measurement method will be explained using examples of call loss and noise.

Figures 4 and 5 illustrate the measurement method for each route, where OSC is an oscillator, LM is a level meter,
NM is a noise voltage measuring device, R is a reference impedance resistance, AMP is an amplifier, and ATT is a resistance attenuator. In this example, the exchange EX-A is a 4-wire type, and the exchange EX-
Although B is an example of a two-wire exchange, both four-wire and two-wire exchanges can be tested in the same way.

In Figure 4a, the reference level signal from the oscillator OSC of the relay test trunk RTT is measured with the level meter LM of the transmission characteristic measuring device TM,
Measure the loss L1 of the first line from RTT to TM. Figure 4b shows RTT as the reference impedance R.
and RTT with TM's noise voltage measuring device NM.
Measure the noise voltage N1 of the first line to TM. Figure 4c shows the oscillator of the transmission characteristic measuring device TM in order to measure the call loss of the second line from the transmission characteristic measuring device TM to the relay test trunk RTT.
A reference level signal is sent from the OSC, passed through the relay test trunk RTT, and then transmitted to the transmission characteristic measurement device TM.
Measure the reception level with the level meter LM. If the loss at this time is L2, the loss on the first line from RTT to TM is calculated as L1 in Figure 4a, so the loss on the second line from TM to RTT is L2 - L1. Become. Note that here the resistance attenuator
The ATT is inserted to eliminate line impedance interference, and the amplifier AMP is installed to compensate for this loss.
The AMP gains are set equal. Similarly, Figure 4d
is the relay test trunk from the transmission characteristic measuring device TM.
In order to measure the noise on the second line to the RTT, the transmission characteristic measuring device TM is terminated with a reference impedance R, and the noise voltage measuring device of the transmission characteristic measuring device TM is
Measure the noise voltage N2 at NM. If the gain of AMP is G, the noise on the second line from the transmission characteristic measuring device TM to the relay test trunk RTT is (N2
-N1-G).

Similarly, in Figure 5, a is the call loss on the second line from RTT to TM, b is the noise on the second line from RTT to TM, and c is the first call loss from TM to RTT.
The call loss of the line, d is the first loss from TM to RTT.
This section shows how to measure line noise. The reason for inserting the amplifier AMP during noise measurement is to prevent noise on the outbound path of the measurement target from being obscured by noise on the inbound path. Also, in case of call loss, use a resistive attenuator.
The purpose of inserting the ATT is to reduce interference between the impedances on the forward and return sides, and by inserting the amplifier AMP in series with it, the amount of attenuation of the ATT can be compensated for.

According to the present invention, the relay test trunk RTT provided at the second station requires a reference level oscillator OSC, a resistive attenuator ATT, and an amplifier AMP for measuring transmission characteristics, which are generally Since it is cheaper than the level meter LM and noise voltage measuring device NM that are required for transmission characteristic measurement equipment, the relay test trunk RTT can be an extremely simple device. On the other hand, since the transmission characteristic measuring device including the level meter LM and noise voltage measuring device NM only needs to be installed at the first central station, automatic transmission characteristic measurement is possible for networks with many peripheral stations. It is possible to introduce it economically.

The measurements in Figures 4 and 5 are switched depending on the timing, and the call loss values L1 to L4 and noise N1 to N4 are automatically measured. From these data, the first and second lines of the outbound and return routes are calculated. Call loss and noise in both directions are calculated, compared with the standard values obtained from the translator TLR, and the results are sent to the printer.
Print on PRT. This method is similar to a known method, and detailed explanation will be omitted.

After measuring the transmission characteristics of the first and second lines for the outbound and return routes, restore only the outbound route, only the return route, or both the outbound and return routes, set the next line using the information from the translator TLR, and check the transmission characteristics. Perform measurements. In this way, all lines can be automatically tested one after another.

The connecting devices CONN1 and CONN2 are controlled by the originating test trunk OTT or the relay test trunk RTT, and each selects one line from the outgoing trunks OGT1 and OGT2. If the selected line is in use, it will be skipped and the next line will be tested, and the skipped line will be tested again at the end, either automatically or manually.

Next, the configuration of each device will be explained in detail. Figure 6 shows the relay test trunk RTT and connection equipment.
This is a configuration diagram of CONN2, where AMP is an amplifier and OSC
is an 800Hz oscillator, REC is a 1000Hz receiver,
ATT is the resistive attenuator, TSEL is the trunk selection circuit,
RCONT is a relay control circuit, No.SEND is a test number sending circuit, A, S, S0 to S4, CO to CN are relay windings, and lowercase letters s, s ₀ to _{s 4} , and sp indicate relay contacts. R is the resistance of the reference impedance.

When a call is received from the exchange EX-A in FIG. 3 to the incoming trunk ICT2 of the exchange EX-B, and the test number is sent as a register signal from the exchange EX-A, the incoming register of the exchange EX-B (not shown) is sent to the incoming trunk ICT2 of the exchange EX-B.
Switch frame is controlled by marker MKR2.
SWF2 operates and connects the incoming trunk ICT2 to the main relay test trunk RTT. At this time the marker
MKR2 tests the selection circuit TSEL of this trunk RTT and selects it after confirming that it is free. In the relay test trunk RTT, relay A operates to hold switch frame SWF2. Exchange EX
- When various control information is sent as a 1000Hz pulse signal from the originating test trunk OTT of A, the 1000Hz receiver REC of the relay test trunk RTT is activated and the relay S is activated. S contact is control circuit
Sends a signal to RCONT and returns outgoing trunk OGT2
In order to select the outgoing trunk, the outgoing trunk number is sent from the outgoing test trunk OTT. As a result, the relay test trunk RTT sends a signal to the connection device CONN2, for example, operates a CO relay, connects the outlet of the relay test trunk RTT to the outgoing trunk OGT2, operates a relay SP (not shown), and operates the test number sending circuit No.SEND. The test number is sent to exchange EX-A. As a result, the incoming trunk ICT1 (Figure 3) of exchange EX-A becomes the incoming test trunk.
Capture TTT.

Next, it is sent from the calling side test trunk OTT.
Relay S is activated by relay control circuit RCONT using a 1000Hz pulse signal and a time limit based on a 1 second pulse.
Operate 0 to S4 and test trunk RTT for relay
Oscillator OSC, resistive attenuator ATT, at the inlet and outlet of
Connect the amplifier AMP to configure the measurement circuit shown in FIGS. 4 and 5. For example, the measuring circuit shown in FIG. 4d only needs to operate when the S2 relay shown in FIG. 6 operates. The measuring circuit shown in FIG. 5a is constructed by the operation of the S0 relay shown in FIG. Further, the measuring circuit shown in FIG. 5c is constituted by the operation of relays S1 and S3. In addition, the oscillator
When OSC, amplifier AMP, and resistor attenuator ATT are not connected, terminate with reference impedance R.

Figure 7 shows the originating test trunk OTT and connection equipment.
This is a block diagram of CONN1, where OSC is a 1000Hz oscillator, CONNC is a connector control circuit, TLRC is a translator control circuit, PRTC is a printer control circuit, TESTC is a test control circuit, No.SEND is a test number sending circuit, and OGTTEST is an output trunk. This is a blank test circuit. a and sp indicate contacts of relays A and SP, which are not shown, respectively. co indicates the contact point of the relay CO of the connection device CONN1.

Based on instructions from a test board (not shown), the outgoing test trunk OTT is controlled by the translator control circuit.
Operate TLRC, start translator TLR, and receive information necessary for the test. As a result, the specified outgoing trunk to be tested OGT1 is emptied by the OGT empty test circuit OGTTEST, and if the specified outgoing trunk to be tested is empty, the connector control circuit CONNC is used to empty the specified outgoing trunk under test OGT1.
Activate the CO relay and use the CO contact to output trunk OGT
1 and the originating test trunk OTT. Relay whose test number is not shown for exchanger EX-B
Through the operation of SP, the communication line is switched to the test number sending circuit No.SEND through the SP contact, and the signal is sent in pulse or multi-frequency signal format. This allows the exchange EX-
B captures the relay test trunk RTT. Subsequent instructions to the relay test trunk RTT are given by sending a 1000 Hz oscillator OSC signal to the communication line through contact a of relay A (not shown).

After the relay SP is restored, the outgoing trunk OGT1 is connected to the transmission characteristic measuring device TM, and the printer control circuit PRTC receives the transmission characteristic measurement results from the TM and sends them to the printer PRT together with the output of the translator TLR for printing.

FIG. 8 shows a block diagram of the transmission characteristic measuring instrument TM.

OSC is the 800Hz oscillator, R is the reference impedance resistance, S0 to S5 are switching relays, lowercase letters _s0 to _s5 are the relay contacts, RCONT is the relay control circuit, MSEND is the measurement result sending circuit,
BPF is a band leaker, AMP is an amplifier, PAD is a variable resistance attenuator, LVC is a level controller,
PADCONT is a pad control circuit, NA is a noise amplifier, TIM is a 5 second time limit circuit, and COUNT is a noise integration counter.

The relay control circuit RCONT operates the S0 to S5 relays according to the timing of the 1 second pulse, and operates the oscillator.
OSC, level meter LM, noise voltage meter NM, calling side test trunk OTT, called side test trunk
Connect to TTT and configure the measurement circuit shown in Figs. 4 and 5. Level meter LM is an imperial leaker
BPF, amplifier AMP, variable resistance attenuator PAD, level controller LVC, pad control circuit PAD
Consists of CONT, level controller LVC
Pad control circuit so that the output is 0 decibels
PAD CONT controls the variable resistance attenuator PAD and sends its value to the originating test trunk OTT via the measurement result sending circuit MSEND. In addition, the noise voltage measuring device NM amplifies the input with the noise amplifier NA, integrates it with a timing of 5 seconds in the time limit circuit TIM, counts the output integral value during that time with the counter COUNT, and sends the measurement result to the sending circuit MSEND.

The embodiment described above is a system that can be easily added to an existing switchboard using the connection devices CONN1 and CONN2, regardless of the type of switchboard.
The transmission characteristics up to 1 and 2 are not measured. As in the conventional example, it is also possible to adopt a method in which the originating side test trunk OTT is accommodated on the input side of the switch frame SWF1, and information is sent to the marker MKR1 to connect to the specified output trunk.

Furthermore, although an example is shown in which a 1000 Hz audio frequency pulse signal is used from the transmitting test trunk OTT to the relay test trunk RTT, it is also possible to use a DC signal or an audio multi-frequency signal.

The main point of the present invention is that the relay test trunk RTT for the destination exchange EX-B is connected to the output trunk OGT1 under test.
By sending a signal to the transmitter and setting the circuit for the return route, it is possible to automatically test whether the transmission characteristics of the outward and return routes meet the standards using the round trip route.

The relay test trunk RTT requires simple equipment such as an oscillator, resistive attenuator, and amplifier, making it possible to save on equipment for a large number of peripheral stations. In addition, in the central exchange EX-A, the conventional transmitting side transmission characteristic measuring device OTM and incoming transmission characteristic measuring device TTM are combined into one transmission characteristic measuring device TM, so that the measurement circuit can be shared. , become economized.

[Brief explanation of the drawing]

FIG. 1 is a relay system diagram showing a conventional measurement method, FIG. 2 is an explanatory diagram showing a method for measuring the transmission characteristics in FIG. 1, FIG. 3 is a relay system diagram showing an embodiment of the present invention, and FIG. 5 are explanatory diagrams showing the transmission characteristic measuring method of the present invention, and FIGS. 6, 7, and 8 are block diagrams showing the configuration of the main apparatus of the present invention. EX-A, B: Exchange, SWF1, 2: Switch frame, OGT1, 2: Outgoing trunk, ICT1,
2: Incoming trunk, MKR1, 2: Control device (marker), CONN1, 2: Connecting device, OTT: Calling side test trunk, TTT: Calling side test trunk,
RTT: Relay test trunk, TLR: Translator, TM: Transmission characteristic measuring device, RRT: Printer, LM: Level meter, NM: Noise voltage measuring device, OSC: Oscillator, AMP: Amplifier, R: Reference impedance, H: Hybrid Circuit, ATT:
Resistance attenuator.

Claims (1)

[Claims] 1. A device for measuring the transmission characteristics of a line between two-wire or four-wire exchanges, which transmits signals transmitted from the first station between a first station and a second station. The first line consists of 2 or 4 lines, and the second line is connected via the first line.
Set up two lines of the second line consisting of 2 or 4 lines originating from the second station selected by sending the number of the second line to the station. Measure the transmission loss and noise in the direction from the second station to the first station by connecting an oscillator to the second station or terminating the audio transmission path in the direction from the second station to the first station. Next, in order to measure the transmission loss and noise of the voice transmission path in the direction from the first station to the second station, a second line was installed to loop back the first line and the second line. The first station measures the round-trip transmission characteristics of the line connected via the relay test trunk of the station, and based on the measurement results, determines the outgoing line characteristics of each of the first and second lines. An automatic transmission characteristic measurement method characterized by determining call loss and noise. 2. The first station is provided with a transmission characteristic measuring device connected to a calling side test trunk, a called side test trunk, and the calling side and called side test trunks, and By sending control information to the second station, a route to connect to the relay test trunk is first set, and then items of transmission characteristics to be measured such as transmission loss and noise and items of the second line to be measured are set. Information on the test type, such as a number, is sent to the relay test trunk, and based on that information, the relay test trunk configures an internal circuit according to the transmission characteristics to be measured, and also configures an internal circuit according to the transmission characteristics to be measured. according to the number of
select the line, create a route to be connected to the transmission characteristic measuring device via the incoming test trunk of the first station, and measure the transmission characteristic according to the test type with the transmission characteristic measuring device. An automatic transmission characteristic measurement method as claimed in claim 1.