Abstract: A high-speed image signal processing system for encoding an image signal, read out at a high speed, into an encoded signal, and/or for recording a decoded signal obtained through a decoding operation on an encoded signal. The image signal, obtained through a scanning operation on an original document, is sent to an encoder through an image bus. A code bus, provided at an output of the encoder, is connected with an encoded-signal memory for storing the encoded signal. A code transfer unit, for performing input/output operation over the encoded signal and for performing transfer of the encoded signal from the code bus to a system bus, is disposed between the code bus and the system bus. A control unit, performing control over the entire system, and a document management data memory, storing management data for performing management over documents stored in the encoded-signal memory, are connected to the system bus.

Abstract: In a high-speed image scanner, a driving method is proposed which needs no timing adjustment between the sensor driving pulse and the motor drive pulse required when the motor shifts from an accelerated state to a constant-speed state. The period of the sensor driving pulse is selected to be equal to or 1/N (N=integer) of that of the motor drive pulse at the time of constant-speed operation, and the phases of the sensor driving pulse and motor drive pulse are controlled independently of each other. Thus, even though the sensor driving pulse and the motor drive pulse are out of good timing, each line of the image can be surely read.