Signal Flow - Sanyo SFX-33 Service Manual

9-2. Signal flow
(a) Transmission
1) The image data of the original conveyed through the reading mechanism is read by the Contact image
Sensor (CIS) and this data is transfered to Ml PCB.
2) In the Ml PCB, the data is amplified, rectified and turned into two values (black and white) or halftone
signal through the image processing, then this data is written into one line memory (SRAM).
3) The CPU reads out and encodes the data written in line memory, then stores the data into the FIFO
(SRAM). At the same time, the CPU transfers one byte data in the FIFO to the MODEM with an interruption
signal requested by the MODEM.
4) Through repetition of above operations, the image data for each line is encoded, modulated through the
NCU.
(b) Reception
1) The signals received from the line enter the MODEM through the NCU.
2) In the same manner as in transmission, the coded data which is demodulated by the MODEM is stored
into the FIFO as one byte data with an interruption signal requested by the MODEM.
3) The CPU reads out and decodes each one bit of the data from the FIFO, and outputs to the thermal head
when each one bit portion of detected data is aligned as one line data.
4) Through repetition of above operation, the received data is printed to the recording paper.
(c) copy
1) In the same manner as image reading in transmission, the image data read by the CIS is
turned into two values (black and white) or halftone signal, then it is stored into one line memory (SRAM).
2) The CPU reads out the data of one line memory, and outputs the data of each line to the thermal head.
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