Scanner Operation Block Diagram; Scanner Component Description - Metrologic MS2020 Stratos series Service Manual

THEORY & OPERATION

SCANNER OPERATION BLOCK DIAGRAM

Scanner Component Description

Photodiode (Detector):
•
Receives the optical signal reflected off the bar code
•
Converts into electrical signal (current) of about 100 nanoamps
Pre-Amplifier:
•
Converts the electrical current to a voltage signal
•
Voltage signal is amplified by a factor of 1000
•
Ambient light noise is filtered out. Resultant signal is routed to the mother board to
primary signal processing circuitry
Signal Processor:
•
Converts analog waveform into a digital signal that can be used by the microprocessor
Decoder:
•
Decoding algorithm decodes digital signals into ASCII characters
©2004 Metrologic Instruments, Inc. All rights reserved
Basic Operation Theory of Standard Bar Code
Scanner
10
MS2020 Stratos Service Manual