G.168-2004/2006 ECHO CANCELLER TESTING SERVICE

SERVICE DESCRIPTION

G.168 echo canceller is important for both telephone equipment manufacturers and service providers. Adaptive Digital Technologies, Inc., a leader in the echo canceller business, offers a G.168 echo canceller test service. Adaptive Digital performs G.168 testing on T-1 or E-1 based hardware that echo cancellation. Testing can be done in Adaptive Digital’s lab, in the customer’s lab, or even in the field.

TEST DESCRIPTION

The following ITU tests are performed:

Test 2: Convergence and Steady state residual and returned echo level tests

2-A: Convergence and reconvergence with NLP enabled

2-B: Convergence and reconvergence with NLP disabled

2-C: Convergence in the presence of background noise

Test 3: Performance under the condition of double-talk

3-A: Double-talk with low cancelled-end levels

3-B: Double-talk stability

a: Double-talk stability with high cancelled-end levels

b: Double-talk stability with low cancelled-end levels

3-C: Double talk test under simulated conversation

Test 4: Leak rate

Test 5: Infinite return loss convergence

Test 6: Non-divergence on narrow-band signals

Test 7: Stability

Test 8: Non-convergence of echo cancellers on specific ITU-T No. 5, 6 and 7 in-band signalling and continuity check tones

Test 9: Comfort Noise

1.) Matching

2.) Adjustment down

3.) Adjustment up

Test 10: Fax

A: Calling station side

B: Called station side

Test 13: Performance with ITU-T low bit rate coders

Test 14: Performance with V-series low speed data modems

Test 15: PCM Offset Test

Each test is run over a variety of conditions in which the following parameters are varied:

Receive signal level (Lrin)

Echo Delay

Return Loss

Hybrid Model

TEST RESULTS

Test results are offered in both summary and detail forms. The summary report consists of a pass/fail spreadsheet for each test trial. A trial is distinguished by the test (Test 5 for example) and the conditions (Lrin, Delay, Return Loss, and Hybrid Model). The detailed data is the raw time domain data that can be viewed in graphical format using a Windows-based viewer that is provided. Each graph shows residual signal level vs. time. Also included in each graph is the ITU mask, making it easy for the user to see the difference between the actual output level and the ITU requirements. Test results are provided either on CD or via FTP download.

TEST SETUP

A diagram of the test setup is shown below.

Configuration A: Single Span

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Configuration B: Two Span

The G.168 tester is connected to the unit under test via T1 or E-1 and via RS232. The T1 or E1 carries the PCM data. The test can be configured to use a single T1/E1 span or two T1/E1 spans. In the case of a single span, the receive and send are placed on different time slots. In the case of two spans, the receive and send are placed on the same time slot in two different spans. The test setup can be modified to use analog interfaces as well.

The RS232 interface is used to control the echo canceller. The unit under test must implement the following commands when issued by the G.168 tester via the RS232 interface:

Reset the echo canceller

Enable echo canceller adaptation

Freeze echo canceller adaptation

Disable NLP

Enable NLP

Enable NLP/CNG

PRICES

Test setup: $2000

Per-day test fee: $1500

Additional fees apply for on-site testing

Discounts are available for customers who license Adaptive Digital’s echo canceller

Typically, a full suite of tests can be run in 5 days if the unit under test operates reliably. A typical suite of tests includes all ITU tests listed above with test condition ranges as follows:

Lrin: -30 dBm to 0 dBm in steps of 10 dB

Delay: 0 msec to 128 msec in steps of 32 msec

Return Loss: 18 dB, 12 dB, 6 dB

Hybrid Models: ITU 1, 2, 3, 4, 5, 6, 7. Three branch