T3 In‑service Testing

In order to avoid disrupting service, Monitor receiver settings must be used when testing a T3 circuit that is in-service. The following measurements are used to check T3 performance during regular maintenance:

•	Vpp measurement

•	Carrier Frequency

•	Frame Bit Errors

•	C‑bit Errors

•	FEBE Errors

•	P‑bit Errors

•	Bipolar Violations

Required Equipment

•	BNC Cables, Anritsu Part Number 3‑806‑169

Measurement Setup Procedure

1.	Confirm that the instrument is in T1/T3 Analyzer Mode, see “Selecting the T1/T3 Analyzer Mode”.

1.	Press the Configuration main menu key.

2.	Use the Up/Down arrow keys or the rotary knob to highlight Line Code and press the B3ZS or the AMI coding submenu key.

3.	Use the Up/Down arrow keys or the rotary knob to highlight Tx Clock and select Recovered.

4.	Use the Up/Down arrow keys or the rotary knob to highlight Rx Input and select Monitor.

5.	Use the Up/Down arrow keys or the rotary knob to highlight Framing and select M13, C‑Bit, or Unframed.

Note	The setup parameters are displayed in the instrument settings summary table on the left side of the measurement display.

6.	Connect to the Monitor jack on one direction of the circuit under test.

Submenu keys for the Configuration Test Mode Menu are described in the “T3 Configuration Menu”.

Rx Signal Measurement Procedure

1.	Press the Measurements main menu key to activate the Measurements menu.

2.	Press the BERT submenu key and check P‑bit errors, C‑bit errors, and FEBE errors. Press the Back key to return to the Measurements menu.

3.	Press the Rx Signal submenu key and verify Frequency and Vpp. When close to the transmitter, the Vpp result should be between 0.72 Vpp and 1.7 Vpp. The Frequency should be 44.736 MHz ± 895 Hz (± 20 ppm).

4.	Move the connection to the other circuit pair and repeat these measurements.

 

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	Anritsu Company
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