Analysis of the jointly adapting and asynchronously configured V.32 modem implementation

The authors describe an implementation of a V.32 modem using new concepts which make it possible to realize a completely digital V.32 modem. The first new concept incorporated is a jointly adapting echo canceler and equalizer where the error signal is derived from the final data decisions. Another new concept used in this implementation is a sample rate convertor algorithm. The receive modem transmits and receives data at the same rate, as determined by the receiving modem. Since the sending modem is typically asynchronous to the receiving modem, a sample rate conversion of the receive data to the rate at which the data were sampled at the sending modem is required in order to recover every data sample transmitted. These concepts are analyzed, and their importance in realizing a completely digital modem is discussed. Results of the actual software solutions are shown along with a block diagram of the final implementation