DIGITAL SIGNAL TRANSMITTER

摘要

PURPOSE:To improve the compression efficiency with simple constitution by applying a data signal to filters for selecting forecasting filters with less number than that of plural forecasting filters and comparing output signals so as to select an optimum forecast filter. CONSTITUTION:A PCM data fed to an input terminal 1 and sampling and coding an analog signal is stored in a block memory 2 and a differential processing circuit 3 takes the secondary difference of the input data. The data read from the memory 2 is fed to a forecasting filter 4 and a maximum absolute value division circuit 5 from which plural forecasting filter characteristics are obtained through selection of switching. The circuit 5 takes the ratio of a maximum absolute value in the block of the PCM data to the data from the circuit 3, an obtained selection signal selects the forecasting coefficient stored in a forecasting coefficient bank 6 so as to select the filter characteristic of the forecast filter 4.