m21604 6.3. Timing issues: length of the preamble 1.2 2009/04/10 04:45:37 GMT-5 2009/04/25 20:02:35.715 GMT-5 Thomas Watteyne Thomas Watteyne watteyne@eecs.berkeley.edu Thomas Watteyne Thomas Watteyne watteyne@eecs.berkeley.edu Thomas Watteyne Thomas Watteyne watteyne@eecs.berkeley.edu Science and Technology en Use the oscilloscope to visualize the energy consumed by a board, you can clearly see the periodic wakeup of the CC2500 (see figure below, lower part).

Energy consumed by the transmitter and the receiver in preamble sampling. To function, the length of the preamble needs to be larger than the check interval CI.

You can see that the time between two successive wake-ups is CI=104ms. Push the button and capture the energy consumed when the board is in transmit mode (see figure, upper part). You can see the series on 50 microframes sent. By zooming in, you can see that one micro-frame is sent every Dcca=3.24ms. Hence, the length of the whole preamble is 50*3.24=162ms, which is larger that the check interval.