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.

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