Notes. Settings 1, 2a/b/c, and 3a/b are used to probe the pulsar orbital Doppler effect (Section 4.1), orbital profile smearing effect (Section 4.2.1), and folding issues with ‘polyco’ (Section 6), respectively. Number of frequency channels for all the setups is 200. For Settings 1, 2 and 3a the TZNSPAN parameter, which characterises the time resolution of the polynomial prediction, is fixed to 3 min. For Setting 3b TZNSPAN is 1 min. The template profile of J0737−3039A is constructed from the MeerKAT observations at L-band with a central frequency of 1283.582 MHz. Narrow and broad Gaussian profiles are simulated with width-period ratio (duty cycle) of 0.006 and 0.1, respectively. The parameter file of PSR J0737−3039A adopts measurements from Hu et al. (2022). To investigate how systematic error behaves under varying conditions, the PSR J0737−3039A ephemeris are modified as follows. Specifically, we alter the original orbital period (P_b = 2.45 h) and the eccentricity (e = 0.088) for a series of tests with the values listed in the table.