Let's summarize the message of the last couple of sections. To transmit to a tag, a reader uses amplitude modulation to send a series of digital symbols. The symbols are coded to ensure that sufficient power is always being transmitted regardless of the data contained within in. The received signal can be demodulated using a very simple power detection scheme to produce a baseband voltage, which is then decoded by the tag logic. The whole scheme is depicted in Figure 19. We can now look forward to discuss how much power a reader needs to transmit, how much power the tag needs to turn on, and more.
