Abstract: Useful subband information which is present in a first audio signal (for example, MPEG 1 Layer II) is discarded in the conventional approach of format conversion, only to be regenerated when encoding to the target format (for example, MPEG 1 Layer III). Instead, in the present invention, this useful subband information is re-used directly or indirectly in order to eliminate the conventional requirement to fully decode to PCM and then encode again.

Abstract: Software for designing, modelling or performing digital signal processing comprises a virtual machine layer optimized for communications DSP. The virtual machine layer allows low MIPS, complex code to interface with high MIPS processes by using APIs presented by the virtual machine layer. The present invention enables software to be written for the virtual machine rather than a specific DSP, de-coupling engineers from the architecture constraints of DSPs from any one source of manufacture.

Abstract: A digital wireless basestation is disclosed which is programmed with a hardware abstraction layer suitable for enabling one or more baseband processing algorithms to he represented using high level software. Commodity protocols and hardware turn a basestation, previously a highly expensive, vendor-locked, application specific product, into a generic, scalable baseband platform, capable of executing many different modulation standards with simply a change of software. IP is used to connect this device to the backnet, and IP is also used to feed digitised IF to and from third party RF modules, using an open data and control format.

Abstract: A method of designing, modelling or fabricating a communications baseband stack, comprising the steps of: (a) creating a description of one or more of the following parameters of the baseband stack: (i) resource requirements; (ii) capabilities; (iii) behavior; and (b) using that description as an input to software comprising a virtual machine layer optimised for a communications DSP in order to generate an emulation of the baseband stack to be designed, modelled or fabricated.