TDECQ Transmitter and Dispersion Eye Closure for PAM4
The Transmitter and Dispersion Eye Closure for PAM4 feature enables FlexDCA to measure the quality of an optical transmitter with its optical link. TDECQ is the optical power penalty of the measured optical transmitter compared to an ideal transmitter. It measures the increase of optical power required for the measured optical transmitter to achieve the same eye opening of the ideal optical transmitter. TDECQ is a PAM4 replacement for an NRZ Transmission Dispersion Penalty measurement.
This feature adds the following items to FlexDCA's Eye/Mask mode:
- PAM4 TDECQ measurement.
- TDECQ equalizer
- Noise Margin (rms). A supplemental measurement which is a system-level test that is similar to TDECQ.
- OOMA. PAM Outer OMA measurement measures Optical Modulation Amplitude (OMA) with a PAM4 signal's level 0 and level 3.
- OER. PAM Outer Extinction Ratio measurement measures Optical Modulation Amplitude (OMA) with a PAM4 signal's level 0 and level 3.
- Ceq. Noise gain measurement measures the noise gain introduced by some FlexDCA Waveform Signal Processing operators.
Because relevant standards require that a TDECQ equalizer be inserted into the signal path, this feature adds a TDECQ equalizer, which is a waveform signal processing operator. The TDECQ equalizer operator uses noise preservation as called out in the standard. Noise preservation compensates for the filter function's side effect of reducing a signals noise for adjacent measurement points. Preserving noise causes the operator to quantify the noise on each point on the operator's input waveform and restore this noise on the corresponding data point on the output waveform.