For record, I took data of beatnote timeserieswith fasted sampling rate on Tektronix TDS 3034C (CTN_OSC_SN01).

• I do see that that positive half cylce looks better than negative half cycle.
• There might be some clipping happing on the negative peak, but can't say for sure.
• Right now, it is 3.48 Vpp, so running moku with 10Vpp input range.
• To the wise people around me, please let me know if there is something glaringly wrong with this signal.

Code and Data