# What is this pulse experiment showing?

The following results in the figure were achieved using Qiskit pulse by doing the following pulse sequence;

{ $$\frac{\pi}{2}$$, delay $$\tau$$, $$\pi$$, delay $$\tau$$, $$\frac{\pi}{2}$$}

The figure is the average of 1024 shots.

This experiment looks very similar to applying the following sequence which is done to measure the T1 time of a qubit which is the it takes a qubit to decay to its ground state from its excited state;

{ $$\pi$$, delay $$\tau$$, $$\pi$$, delay $$\tau$$, $$\pi$$ }

I am trying to understand what the first experiment is used for and what the the results from the figure even show.