  The sensing matrix of a compressive system impacts the stability of the
associated sparse recovery problem. In this paper, we study the sensing matrix
of the modulated wideband converter, a recently proposed system for sub-Nyquist
sampling of analog sparse signals. Attempting to quantify the conditioning of
the converter sensing matrix with existing approaches leads to unreasonable
rate requirements, due to the relatively small size of this matrix. We propose
a new conditioning criterion, named the expected restricted isometry property,
and derive theoretical guarantees for the converter to satisfy this property.
We then show that applying these conditions to popular binary sequences, such
as maximal codes or Gold codes, leads to practical rate requirements.
