TEM 1D inversion

I have some field TEM data for 1D inversion and trying to define a RawWaveform (basically to get the field waveform); howver, it gives me this error:

→ [114](file:///C:/Users/au756649/AppData/Local/anaconda3/envs/SimPeg_FrostC/Lib/site-packages/SimPEG/electromagnetics/time_domain/simulation_1d.py:114) times = rx.times - wave.time_nodes[:, None] [115](file:///C:/Users/au756649/AppData/Local/anaconda3/envs/SimPeg_FrostC/Lib/site-packages/SimPEG/electromagnetics/time_domain/simulation_1d.py:115) times[times < 0.0] = 0.0

AttributeError: ‘RawWaveform’ object has no attribute ‘time_nodes’

Any ideas how to solve this? see image for the waveform.