MODMER / Segédlet / Mûszerek/ HP 37724A

HP 37724A (SDH/PDH) interface tester

With the help of HP 37724A interface tester we can make test on the following interfaces:

ITU-T G.703 2048 kbit/s PDH (PCM interface)
ITU-T G.703 34 Mbit/s PDH
ITU-T G.703 140 Mbit/s PDH
ITU-T G.703 G.708 155 Mbit/s SDH (STM-1 interface)
ITU-T G.708 622 Mbit/s SDH (STM-4 interface)

This measuring instrument was designed first and foremost for testing the interfaces of SDH, then we will emphasize measurements can be executed on these interfaces, and we refer to the general description of measures on PDH interfaces.

We emphasize from test executable on SDH interfaces:

• Payload Testing (mapping, transmission, demapping) – Here we can test, how can the tested equipment multiplex the digital signal flows with smaller speed to the STM frame, and how can raise the tested equipment a signal flow with smaller speed from the STM frame.
Network Equipment Stress Testing
- Frame synchronization
- Optical clock recovery stress
- Desynchroniser Stress
- Pointer processor test
- Line jitter tolerance testing
Network Equipment Stimulus/Response Testing
- Alarm stimulus/response testing
- Performance monitor stimulus/response
- MSP stimulus/response
In-Service Performance Monitoring
- In-service performance monitoring
- PDH in-service tributary performance monitoring
- PDH Cross Multiplex Testing
- Measure 2 Mbit/s Structured Signal from 140 Mbit/s Structured Signal
- Frequency Offset Tolerance Testing
DCC testing
Transmit static overhead
Transmit overhead sequence
Receive overhead monitor
Receive overhead sequence

Accesses of measuring instrument:

STM-1 interface can be found on the face:

STM-1 OUT ericcson cable
STM-1 IN ericcson cable
2M REF IN ericcson cable + 3 pol CF external 2 Mbit/s clock signal access

Opticalinterface:

HP 37776A 155/622 MB/S OPTICAL INTERFACE 1310 NM
HP 15744A OPTICAL COUPLER 1310/1550 NM - splitter in the cover (IN +20DBM MAX, OUT 90% 0,5 DB, TEST 10% 10 DB)

Payload (2M...140M), clock signal, jitter resource cables are on the backboard:

Handling of the measuring instrument:

Switching on with the switch on the face of the instrument.

Handling of the tester can be made in the menu system.

Block diagram of the measuring gadget:

      +------------------------------------------------------------+
           +-----------------+                                     |
           | Digital Signal  |                                     |
           | Generator       |                                     |
           +-------v---------+                                     |
                   |                                               |
           +-2/34/140 Mbit/s-+      +-155/622 Mbit/s-+   +-------+ |
    2 o-<--| Internal        |-->---| STM-1/4        |->-|Cu if. |-o  155
   34 o-<--| Payload         |   +>-|                |   +-------+
  140 o-<--| Generator and   |-<-|+ | Transmitter    |   +-------+
  Mbit/s   | Test Interface  |   || |                |->-|Opt.if.|-/  155/622
   OUT     +-----------------+   || +----------------+   +-------+    Mbit/s
               -Ext. payload---->||                                   OUT
                                 ||
           +-2/34/140 Mbit/s-+   || +-155/622 Mbit/s-+   +-------+
    2 o->--| Internal        |->-+| | STM-1/4        |-<-|Cu if. |-o  155
   34 o->--| Payload         |    | |                |   +-------+
  140 o->--| Receiver and    |--<-+-| Receiver       |   +-------+
  Mbit/s   | Test interface  |      |                |-<-|Opt.if.|-/  155/622
   IN      +-----------v-----+      +----------------+   +-------+    Mbit/s
                       |                                           |  IN
           +-----------v-----+                                     |
           | Digital Signal  |                                     |
           | Receiver        |                                     |
           +-----------------+                                     |
      +------------------------------------------------------------+

We can boot menus to the display with the buttons at the right side of the built-in display:

TRANSMIT - measure selection, giving the measuring parameters
RECEIVE - selection of display of measuring results
RESULTS – selection of the measuring result display
GRAPHS - display of measuring results in graphic format
OTHER - measuring tool setup, optional parameters

We can move in the menu appearing on the display with the arrow buttons, and we can choose from the offered values with the buttons at the bottom of the display.

We can execute the start of measuring, stop of measuring, putting in errors with the following buttons:

ACTION
SINGLE ERROR
START/STOP
ADJUST POINTER
FREEZE DISPLAY
PRINT NOW
LOCAL (GPIB) Next we will review TRANSMIT RECEIVE and RESULTS menus.