I (Tim Thorpe) left Cambridge University Engineering Department in 1989 to become a freelance DSP developer and consultant. In 2001 my business was incorporated as Romsey DSP Limited. It is basically a one-man company, but when I have needed more manpower or to deal with areas outside my experience this has been provided by subcontracting locally, mainly to ex-colleagues from the University.
My main area of of expertise lies in speech and audio compression. Having implemented many codecs for use in mobile telephone handsets, I've also become very practiced at writing efficient and compact DSP assembly code, and testing it. In addition to compression algorithms, I've completed consultancy or development contracts on echo cancellation, telephone modems, channel coding and decoding, noise reduction, and digital implementation of analogue standards.
Standard codecs that I've implemented (and converted to fixed-point where required) include IS-54 VSELP, PDC VSELP, PDC PSICELP, G.721, G.722, G.722.1, G.728, G.729, GSM Half-rate, AAC, WMA Standard, WMA Pro.
I've programmed many types of processor in the last decade, but recently most of my work has been on the TI TMS320c55x series, and Broadcom's Videocore.
My clients have included British Telecom, Nokia, Philips, Radioscape, Broadcom and Thales.