Metrologic Instruments IS4921 User Manual
Page 54
48
EMI
The IS4920 consists of a 400MHz processor running a 100MHz SDRAM bus and a camera interface capable
of image transfer up to 48MHz. The IS4920 series engine was designed to meet EN55022 Radiated Class B
emission limits. Using the system shown below, the decode engine was able to meet these requirements with
an input voltage VIN = 3.3V and the camera interface operating at its maximum frequency of 48MHz.
Figure 41. IS4920 EMI Test System
Components used in IS4920 EMI test system
Part Number
Part Description/Function
IS4920-USB
Imaging decode engine
77-77104A
Imager to Decode Flex cable assembly (shielded)
77-77095A
IS4920 test adapter board
52-52828
USB cable (A to B)
19-00329
12 pin Host Flex cable
Given the decoding platform architecture described above, the harmonics of 48MHz and 100MHz were most
prevalent.