13.56MHz 10% ASK modulation

Recently I want to do a 13.56MHz ISO/IEC15693 reader, according to the ISO/IEC15693, the reader send command to the tag use ASK with pulse position encoding, but there are two modulation indexes are used 10% and 100%, so I know how to realize 100% modulation, but don't know how to realize 10% modulation, can somebody help me?
The attachment is ISO/IEC15693-2
Attachment:ISOIEC15693-2.pdf

Amlitude modulation means varying the amplitude of a carrier. What's your problem with it? In analog design, e.g. a programmable voltage divider or a multiplier can achieve it.

Hello FvM!
Thanks for your suggest, these days I'm busy at another project, so after a few days I will do a PCB,
and tell you the result!