The N -dimensional time domain, ( t1
, t2 , …, tN ),
is thus sampled at discrete points on the hyperplane $$ t \cdot
\vec{p}_{1} \left( {\vec{\varphi }} \right) + t_{N} \cdot
\vec{p}_{2} $$ (Fig. 5 a), where t is a time
parameter along $$ \vec{p}_{1} \left( {\vec{\varphi }} \right) $$
in the ( N −1)-dimensional time domain subspace of the
indirect dimensions, and tN is the
time axis for the direct detection.