The explicit form of the canonical angle operator is found and the iso
vector rotor is quantized in canonical relative variables ensuring the
exact separation of the spurious mode. The main characteristics of th
e resulting joint mode, together with the low- and high-frequency part
s of the split mode are obtained. It is found that the isovector rotat
ional mode exhausts all the non-spurious M1 strength at low and high e
nergy, providing a strong support for the interpretation of all the or
bital 1+ excitations as a scissors mode. Self-consistent residual inte
ractions do not change the non-spurious restoring force of the deforme
d potential. Simple numerical estimates, derived from a schematic defo
rmed oscillator, are in a good qualitative agreement with microscopic
RPA results. Relationships with the results of the two-rotor model and
the microscopic realization of the scissors state are established.