IT-102, IT-108 Simulator-Tester of Е1, Е2 Streams

     An IT-102 simulator-tester of Е1 streams (a tester hereafter) is intended for a testing of E1 digital stream transmitting paths (a PDH system ) and digital radio relay stations. The testing is effected with a calculation of error rate and other parameters according to the recommendations ITU-T G.821, G.826, M.2100. The inner structure of the streams is not analysed.
    The device enables effecting efficient measurements of a network and a long-term monitoring .
    The measuring results are represented in the form of tables and diagrams.
    Device operation is effected with the help of a graphical interface.
     A IT-108 simulator-tester of streams is intended for testing of E1 and E2 digital stream transmitting paths (a PDH system ) and digital radio relay stations. The principle of operation of the device is analogous to the principle of operation of the IT-102
    The simulator shapes unstructured streams E1 and E2 which are a pseudorandom pulse sequence.

Product specifications	Stream E1	Stream E2
Transmission speed	2048 Kbit/s	8448 Kbit/s
Maximum relative error of transmission speed	±25ppm	±15ppm
Used linear code	AMI; HDB3	HDB3
Input and output resistance	120 Ω	75 Ω
Interface type	symmetric	coaxial
Allowable attenuation of an input signal	12dB - Short Haul mode 14dB - Long Haul mode	20dB
Test signal structure	Pseudorandom sequence or a loop constant 8 bit
Error rate measurement range	from 10^-10 to 10^-2
Monitoring range (parameter accumulation)	from 15 min. to 7 days
Energizing	From a power adapter or from accumulator batteries
AC mains voltage	220V ± 20%
AC mains frequency	50 Hz
Mains power consumption (including a charger)	≤ 20 W
Operation time from built-in accumulators	≥ 2.5h
Weight	0.4 kg
Dimensions	87x173x39 mm

Preparation and Turning on of Tester

     Before tuning on the device install the accumulators included into a delivery set into a battery compartment. Connect a power cable of a mains supply unit, connect a supply unit to a mains.
    Press the "ВКЛ/POWER" button to turn on the tester. A static picture will be displayed within 0,5 s. During this time initialization and configuration of internal tester devices occurs.
    The tester transfers into a measuring mode afterwards. A metering table is displayed the appearance of which is shown in fig. 1.

Figure 1 - The appearance of a measuring mode

BER - is error rate, Err - an error counting device, Sync - is a skip counting device, FRQ - is the frequency of the clock pulses regenerated during reception.

While having bit errors a LED flashes for a short time and the tester generates an auditory message (it can be deactivated in the menu of settings). If there is a great error stream an auditory message is turned off automatically.

Figure 2 - The appearance of a dialog box "selection from multitude" on the basis of
a menu of standard choosing to present reports

    A status line located in the upper part of the display shows the symbols characterising a supply source, an accumulator charge and current time.

    Key Function:
    / < / , / > / - moving of a pointing tool (a dot) over the dialog box options;
    /Отмена/Cancel/ - exit from the dialogue box without any actions
    /Выбор/Choice/ - fulfilment of actions in the chosen mode (for example displaying of a chosen report type).

Reduction of the measured parameters according to the G0.821 standard
No	Shorthand name	Parameter designation
1	ES	Quantity of seconds with errors
2	%ES	Second percentage with errors
3	SES	Quantity of seconds heavily damaged by errors
4	%SES	Second percentage heavily damaged by errors
5	FES	Quantity of seconds without errors
6	UAT	Time of channel unavailability

Reduction of the measured parameters according to the G.826 standard
No	Shorthand name	Parameter designation
1	ES	Quantity of seconds with errors
2	ESR	Frequency of seconds with errors
3	SES	Quantity of seconds heavily damaged by errors
4	SESR	Frequency of seconds heavily damaged by errors
5	UAT	Time of channel unavailability

    A time monitoring is effected using three parameters: error rate, quantity of errors, quantity of skips. A skip may occur while sliding of a received sequence by 1 bit or more or while having a high error rate, or while disappearing of a test sequence of reception. Display error rate corresponds to the maximum value per a single observation period specified on a diagram by one dot of a horizontal axis (a sampling period). A mode of bit error accumulation displays a decimal logarithm of error sum per a sampling period. A mode of skip accumulation is analogous to a mode of bit error accumulation.
    A set monitoring period - 15 min, 1 h, 8 h, 24 h, 7 days.
    While having a power supply blackout the monitoring results are saved in a long-term memory of the tester.

Fig.3 - The appearance of a monitoring box