  We propose a new approach to measure differential radial velocities, mainly
for single-lined spectroscopic binaries. The proposed procedure - TIRAVEL
(Template Independent RAdial VELocities) - does not rely on a prior theoretical
or observed template, but instead looks for a set of relative Doppler shifts
that simultaneously optimizes the alignment of all the observed spectra. We
suggest a simple measure to quantify this overall alignment and use its maximum
to measure the relative radial velocities. As a demonstration, we apply TIRAVEL
to the observed spectra of three known spectroscopic binaries, and show that in
two cases TIRAVEL performs as good as the commonly used approach, while in one
case TIRAVEL yielded a better orbital solution.
