Complex sentence: In preparation for the coming landings, Allied scientists had worked on a number of techniques for obscuring the size and disposition of an invasion force, such as radar jamming using wireless sets and chaff (known by the codename Window).
Split into simpler sentences: In preparation for the coming landings, Allied scientists had worked on a number of techniques for obscuring the size and disposition of an invasion force. For example, radar jamming using wireless sets and chaff (known by the codename Window).