pwm-rssi

I have read in the last data sheet for (ZigBee RF Modules by Digi International) in the end of page 97: The RSSI PWM runs at 12MHz and has 2400 total counts (200us period). Is the 200us period for one pulse or for all the train of pulses generated??
Can anyone pliz explain to me?is the 2400 is number of pulses?
I appreciate any prompt acknowledgment.