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Enhanced Multi Channel Bit Error Rate Testing Over T1/E1


Overview | Operation | Main Features | BER Patterns
Real-Time Tabular & Graphical Display | Offline Graphical Display
Comparison with other GLís BERT Applications | Standard BERT | Multi-Channel BERT


Overview

The enhanced Bit Error Rate Tester measures the correctness of data received on T1/E1 lines (contiguous and non-contiguous timeslots, sub-channels) according to a repetitive fixed or pseudorandom pattern for a given transmission. The application also supports sub-channel selection (fractional BERT within a timeslot) for finer control of testing on individual bits.

 
 
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The application generates/detects framed, unframed, fractional, and sub channel BER patterns with a variety of standard static and pseudorandom data patterns such as QRSS, All Zeros/ Ones, CSU and NIU Loop-Up/Loop, and user defined patterns.

The Bit Error Rate Testing can be performed simultaneously in real-time or off-line mode on multiple cards along with a consolidated result view in tabular / graphical formats. The Tx and Rx settings can be independently controlled or set as coupled.


Operation

The applicationís operational system includes a data receiver unit, error & pattern generator unit, a comparator, and a statistics-counting unit.

The data receiver unit allows the data to be captured in real-time and load the resultant files in offline. The comparator receives incoming data & generated patterns, compares them, and determines whether both are the same or not, and outputs a comparison result. The statistics unit counts the number of bit errors based on the comparison result.




Main Features

  • Testing on multiple cards

    Supports testing on multiple cards simultaneously with consolidated result view

  • Independent settings for Tx and Rx configuration

    Tx and Rx settings for multiple cards can be independently controlled or coupled.

    Screen Shot of Tx and Rx Configuration Settings Window

  • Quick view of the status and trouble indication

    The icon on the tree view will show the status (BERT is running or stopped) as well as indicate any kind of errors through the red, green or yellow alarms. A trouble is also indicated through an alarm, allowing the users to look at the results for further investigation.

  • Save and Load configuration settings

    With this feature, the configuration settings created for a particular scenario can be saved for later use. These saved profiles can be made available to address various testing conditions.

  • Timeslot Selection (Fractional BERT)

    Supports non-contiguous timeslot for performing fractional BERT and sub-channel selection (Fractional BERT within a timeslot) for finer control of testing on individual bits. Timeslots of 1 to 31 for E1 and 0 to 24 for T1 and Sub-channels of 00 to FF are available for testing.

    Screen Shot of Timeslot Selection Window

  • Error Insertion

    The application can automatically insert logic and BPV errors at regular intervals of time (secs) or insert just single bit errors into the incoming stream.

  • Error Rate

    Supports predefined error insertion rate and user defined error rates ranging from 0.01 to 1e-009.

  • Bit Patterns (Static and User-defined)

    Generates various static bit patterns such as-QRSS, 25-1, 29-1, 211-1, 215-1, 220-1, 223-1, All ones, All zeros, 1:1, 1:7, 3 in 24, CSU Loop-Up (0001), CSU Loop-down (001), NIU Loop-UP (11000), and NIU Loop-Down (11100), and user-defined patterns of size up to 32 bits

    Screen Shot of Bit Patters Selection Window

  • Events and Error logging

    Events can be logged for extended periods. This information is recorded in *.CSV file formats. The length of these result files is limited with defined time duration or file size.

    Screen Shot of Error Logging Window


BER Patterns

The framing patterns available in Enhanced BERT can be Unframed or Framed. Entire T1/E1 bit rate is used to transmit /receive the selected pattern. For T1, the entire timeslots are used for pattern data and not for framing bits. However, for E1 cards, timeslot 0 is used for pattern data and not for framing bits.

BERT application has various available predefined data patterns:

  • Quasi Random Signal Source (QRSS):

    The length of this pattern is 1,048,575 bits. This pattern is generally used as a test signal to test T1 lines.

  • 26-1 (63):

    Here a maximum of five consecutive zeros and consecutive ones are generated. The length of this pattern is 63 bits.

  • 29-1 (511):

    Here a maximum of eight consecutive zeros and nine consecutive ones is generated. The length of this pattern is 511 bits.

  • 211-1 (2047):

    Here a maximum of ten consecutive zeros and eleven consecutive ones is generated. The length of this pattern is 2047 bits.

  • 215-1:

    Here a maximum of 14 consecutive zeros and 15 consecutive ones is generated. The Length of this pattern is 32,767 bits.

  • 220-1:

    Here a maximum of 19 consecutive zeros and 20 consecutive ones is generated. The length of this pattern is 1,048,575 bits. See definition of QRSS.

  • 223-1:

    Here a maximum of 22 consecutive zeros and 23 consecutive ones is generated. The length of this pattern is 8,388,607 bits.

  • CSU (Channel Service Unit) Loop Up Code:

    The framed sequence consists of a repetitive 5 bit sequence "00001" with the framing bit in its normal position. The unframed sequence consists of the same repetitive 5bit sequence without a framing bit.

  • CSU Loop Down Code:

    The CSU Loop Down Code is a 3 bit sequence "001" and is similar to the CSU Loop Up Code in the unframed and framed modes.

  • NIU Loop UP and Loop Down codes:

    Loop up code is of 5 bits ('11000' as defined in application) and Loop down code is of 3 bits (111).

  • All Ones, All Zeroes:

    Itís a Static pattern of continuous ones or zeros respectively.

  • 1:1:

    It's a Static pattern of alternating ones and zeros.

  • 1:7:

    It's a Static pattern with one "1" and seven "0"s.

  • 3 in 24:

    It's a Static pattern with three "1"s in a string of 24 bits User Defined User definable 24-bit static pattern.

  • User Defined Static Pattern:

    It is a Static pattern with 32-bit pattern. Available bit patterns are binary 1ís or 0ís / HEXA values or all ones / all zeroes values.


Real-Time Tabular & Graphical Display

Tabular Result for Frame Errors, Bipolar Violations and Logic Errors

  • Status/Errors:

    "Pat Sync" is displayed in this field if BER is less than 0.019. "No Pulses" is displayed if no signal is received.

  • Total Bit Errors:

    This is the Count of total number of bit errors detected after Pat Sync is achieved.

  • Err Rate (Cont):

    This is the ratio of Total Bit Errors to the total number of bits received i.e., the BER.

  • Err Second (ES):

    It is the number of seconds with one or more errors detected during the Pat Sync condition.

  • Err Free Second (EFS):

    It is the number of seconds with no errors detected during the Pat Sync condition.

  • %EFS:

    The ratio of EFS to Test Sec multiplied by 100, where, Test Sec = Test Run Sec - Loss of Pat Sync Sec.

  • Severely Err Sec (SES):

    It is the number of Test Sec with a Bit Error Rate worse than 1*10-3 in each second.

  • %SES:

    This is the ratio of SES to Test Sec multiplied by 100.

  • Degraded Minutes:

    The number minutes with a Bit Error Rate in each minute equal to or worse than 1.0*10-6

  • %Dmin:

    This is the ratio of Degraded Minutes to the Test Run Minutes. Loss of Pat Sync time is included in Test Run Minutes.

  • Loss of Sync Count:

    The count of number of times the pattern sync was lost. Pat Sync is automatically re-established if lost.

  • Loss of Sync Sec:

    The total number of seconds the pattern sync was lost. If Pat Sync was momentarily lost and re-established during 1-second interval (one or more times), then this count is incremented by one.

  • Loss of Pat Sync Threshold:

    If the BER is worse than 0.19 (approximately 1 error in bits on average) during any poll of the pseudo random bits, a Loss of Pat Sync is declared. A poll occurs with a frequency of once in 3 to 10 multiframes depending on whether a fast Pentium or a fast 386-host computer is used.

  • Available Seconds:

    The number of seconds with a BER in each second better than .0*10-3

  • %Available Sec:

    It is the ratio of available seconds to the Test Run Sec multiplied by 100. Loss of Pat Sync time is included in Test Run Sec.

  • Unavailable Seconds:

    It is the number of seconds with a BER in each second worse than 1.0*10-3. The count begins at ten and after ten consecutive unavailable seconds has been detected.

Graphical Result

The Error Rate Vs Time graph of the bit error test results is displayed. For real-time graph, the predefined or the user defined bit pattern and the errors can be inserted.

Any of the events such as LOGIC_ERROR, BPV, or FRAME_ERROR can be set for the displayed. The graph depicts the start and end of the x-axis and for the entire file.


Offline Graphical Display

For Offline graph display the saved (*.egf) files are loaded for analysis. The entire file selected for analysis can be played back for complete view of the graph.


Comparison with other GLís BERT Applications

MCBERT

  • Supports both real-time and offline analysis. In real-time, data along with pattern file is transmitted on timeslots and sub-channels for analysis. In offline, the stored data file is loaded and compared with the pattern file
  • Patterns files are externally loaded
  • Provides results in tabular format and logs results in *.txt files
  • Supports Multiple 64kbps (56kbps) independent stream channels, n x 64kbps hyperchannels (where n = 1..24 T1, 1..32 E1; contiguous timeslots), and multiple subchannels n x 8kbps (eight subchannels per timeslot). For example, for T1 it could be up to 24 x 8 separate 8kbps subchannels

For more information, please visit Multi-channel BERT page

Basic BERT

  • Supports real-time generation of patterns, and errors (Logic error, BPV) on framed, unframed, full-frame, fractional, and fractional with drop and insert frames.
  • Sends/Receives BER pattern with Tx and Rx internally coupled
  • Supports 16 static BER patterns (QRSS, 25-1, 29-1, 211-1, 215-1, 220-1, 223-1, All ones, All zeros, 1:1, 1:7, 3 in 24, CSU Loop-Up (0001), CSU Loop-down (001), NIU Loop-UP (11000), and NIU Loop-Down (11100)
  • Analysis and logs results in *.txt files

For more information, please visit T1/E1 Basic Bit Error Rate Test page

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