  The recent realization of single electron sources let us envision performing
electron quantum optics experiments, where electrons can be viewed as flying
qubits propagating in a ballistic conductor. To date, all electron sources
operate in a periodic electron injection mode leading to energy spectrum
singularities in various physical observables which sometimes hide the bare
nature of physical effects. To go beyond this, we propose a spread-spectrum
approach where electron flying qubits are injected in a non-periodic manner
following a pseudorandom binary bit pattern. Extending the Floquet scattering
theory approach from periodic to spread-spectrum drive, the shot noise of
pseudorandom binary sequences of single electron injection can be calculated
for leviton and non-leviton sources. Our new approach allows us to disentangle
the physics of the manipulated excitations from that of the injection protocol.
In particular, the spread spectrum approach is shown to provide a better
knowledge of electronic Hong Ou Mandel correlations and to clarify the nature
of the pulse train coherence and the role of the dynamical orthogonality
catastrophe for non-integer charge injection.
