Investigation of states switch properties of PSR J1946 + 1805 with the FAST

We have carried out a detailed study of the single pulse of PSR J1946 + 1805 with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We reassessed the nulling fraction (NF) to be 57.5%. We also reverted the multiple drifting modes and obtained their drifting parameters. It is found that, for this pulsar, there exists the dwarf pulse at the beginning or end of the burst state, and the duration of dwarf pulse usually is one to two pulse periods. Additionally, we observed that there are scattered dwarf pulses detected in the null state. Detailed analysis of the fraction of linear polarization for all dwarf pulse is presented. It is worth noting that relative to normal pulses these dwarf pulses have a very high fraction of linear polarization, even more than 90%. We proposed that the dwarf pulses appearing at the beginning or end of the burst state may be a common behavior, which is important to understand the physical mechanism of the process of switching between two states.