AWR1243: ADC output format settings

Part Number: AWR1243

Hi,

The following settings are allowed for the ADC output format:

ADC OUT FMT 2 Bits Description
b1:0 Value Definition
00 Real
01 Complex 1x (image band filtered
out)
10 Complex 2x (image band visible)
11 Pseudo Real
b15:2 RESERVED
0b00000000000000

Can you please explain what the difference is between  Complex 1x and  Complex 2x?

Thanks.