  To study the characteristic features of relativistic bound systems, the
Bethe-Salpeter equation (BSE) for two equal mass spin 1/2 particles (like the
deuteron) is solved in the cm-frame for a covariant separable interaction
kernel. For that purpose the BSE is transformed to an eigenvalue problem which
is diagonalized numerically. The Bethe--Salpeter amplitudes (BSAs) are obtained
straightforwardly from the resulting eigenvectors. Only positive parity
solutions of the eigenvalue problem are considered. To correlate the BSAs to
standard quantum mechanical wavefunctions, the corresponding
equal-time-wavefunctions (ETWs) are calculated. A decomposition of BSAs and
ETWs in partial waves in angular momenta and parity is performed. As a first
application elastic electron-deuteron-scattering in the impulse approximation
(IA) is considered. The charge, magnetic and quadrupole formfactors $F_C(k^2)$,
$F_M(k^2)$, $F_Q(k^2)$ and tensor polarizations $\tilde{t}_{20}(k^2)$, $t_{20}
(k^2,\theta_e=70^{\circ})$ are obtained from three independent matrix elements
of the deuteron current in the Breit-frame of elastic
electron-deuteron-scattering. Additionally, the formfactors $A(k^2)$ and
$B(k^2)$ of the Rosenbluth formula are calculated.
