Abstract: A system for distributing educational information in digital form to a plurality of schools simultaneously transmits the information via a satellite (15) to FM stations (18) which retransmit to schools having receivers for receiving the information and a main computer (101) for storing the information. Access to the information is subsequently provided to a plurality of students via classroom computers (111) and individual terminals (121). Usage and performance data is automatically stored in the main computer (101) and sent to the sender by dial-up modem (105) to keep track of usage and to permit billing usage and royalty charges.

Abstract: A digital partial response filter is disclosed. The digital partial response filter has particular application in an FM subcarrier (SCA) digital data transmission system wherein digital data is frequency modulated on an F.M. subcarrier. The partial response digital filter includes a digital memory wherein digitized samples of the partial response channel response to a representative input digital data symbol are stored and digital adding means for cumulatively summing the digitized samples in groups so as to produce the partial response channel response to an input digital data stream.