Transformation of narrowband speech into wideband speech with aid of zero crossings rate

An innovative technique, for narrowband to wideband transformation of speech signals, is proposed. The zero crossings rate is used to adaptively control the gain of the synthesised upper band speech leading to significant performance improvement over an existing technique. Results are in fact comparable to more complex techniques. The technique can be implemented at the receiving end alone as it does not require any side information to be transmitted and can be easily implemented using finite impulse response digital filters.