Integrated Device Technology's family of high-definition PC audio codecs feature the DDX-based class-D modulation technology developed by Apogee Technology. This three-state modulation technique extends battery life, eliminates pops and clicks, and reduces electromagnetic interference in notebook and desktop audio systems. The series integrates equalisation, dynamics processing and filtering in hardware to enhance audio output, with features implemented in software to enhance microphone inputs such as acoustic echo cancellation, noise suppression and beam forming for unified communications. The devices include an integrated high-pass filter to prevent speaker damage by blocking low frequency content the output transducers cannot reproduce. When used with the integrated band-pass filter, 2.1 speaker configurations are possible using the mono subwoofer output. It has an integrated combo jack that allows headsets to use a single port for the microphone input and headphone output. There is also an option for dual HD Audio and Inter-IC Sound bus interfaces to facilitate notebook docking and connection of auxiliary audio devices with lower costs. The IDT 92HD91 and 92HD99 are stereo-class class-D codecs available in 48-QFN and 40-QFN packages, respectively. The 92HD98 is a mono version of the 92HD99 in the 40pin QFN package.
