AE6980T Optical Automotive Ethernet Tx Compliance Test Software

Accurately Qualify the nGbase-AU Optical PHY with TDFOM-Assisted Measurements

Optical Automotive Ethernet uses optical fiber to transmit data between systems within a vehicle. IEEE Std 802.3cz defines optical connectivity standards supporting single-lane data rates up to 50 Gbps, with up to four in-line connectors and a maximum reach of 40 meters over OM3 multimode glass optical fiber. The key advantages of Optical Automotive Ethernet include superior electromagnetic compatibility (EMI/EMC), low signal attenuation and interference, high data rates, and reduced cable harness weight.

Key Features

• Compliant test specs: IEEE 802.3cz:2023 (IEEE 802.3:2020 Amendment 7), and Open Alliance TC7 test house D1.0:2025 
• Supported data rate: 10 Gbps (with 25 Gbps support in the future)
• Supported TDFOM measurements: 
  • TDFOM 
  • TDFOM-assisted OMA
  • TDFOM-assisted ER
  • TDFOM-assisted AOP (OMA to AOP ratio, defined in 802.3cz as ꝩ in 166.6.4.13.2)
  • TDFOM-assisted OAR 
• Supported oscilloscope: Keysight N1092A and N1092C
• Supported clock recovery: Keysight N1077B
• Supported optical signal wavelengths: 850 nm, 980 nm, 1310 nm, 1550 nm 
  • Note: 980 nm wavelength selection requires user optical calibration on FlexDCA with a 980 nm CW optical source and a power meter.
• Supported channel loss compensation by manually applying channel loss of each channel component to move the measurement point from TP3 to TP2.

Tests Provided

• TDFOM
• TDFOM OMA
• TDFOM ER
• TDFOM AOP
• TDFOM OAR

In the IEEE 802.3cz standard, the Transmitter Distortion Figure of Merit (TDFOM) is the primary metric for evaluating the quality of an optical transmit signal to ensure transmitter–receiver interoperability. TDFOM represents the optical power penalty of a measured transmitter compared to an ideal transmitter. It is also used to calibrate reference transmitters for assessing the quality of receivers with compliant transmitters. To derive TDFOM, the optical signal is filtered, sampled, noise-added, and equalized according to a specified reference receiver. The maximum noise power supported for a given BER is then calculated, providing a measure of signal quality. Higher TDFOM values—indicating tolerance to less noise power—correspond to increased receiver sensitivity penalties and reduced signal integrity. Conversely, lower TDFOM values correspond to better receiver sensitivity and higher signal integrity.

Ordering Information

• Keysight DCA-M sampling oscilloscope.
• Keysight Optical Clock Data Recovery.
• nGBASE-AU Optical Automotive Ethernet Tx Test Software
• FlexDCA sampling oscilloscope software
• Software maintenance is available for 12-month increments.