Simplified illustration of effects related to the deflection of A’s radio signals (solid red) in the gravitational field of B (top down and side perspective). The observer is located at a large distance along the x-axis. Apart from modifications in the propagation time due to a curved path in the gravitational field of B (lensing), one has a longitudinal deflection delay () due to the fact that the pulsar has to rotate by more than 360° between two pulses while approaching the conjunction. After conjunction, it is less than 360°, which makes pulsar signals arrive earlier at the observer. In addition, there is a latitudinal effect, due to a latitudinal shift in the emission direction towards the observer. This can lead to changes in the pulse profile since the line of sight cuts a different part of the emission region, which can also be accompanied by changes in the pulse arrival times (more details in Sects. 5.1 and 5.2).