Patent ID: 7825706

Claim:
A phase locked loop (PLL) that sets gain automatically, the PLL comprising: a frequency discriminator for providing a first signal that represents the difference between a first frequency and a second frequency; and a comparator coupled to the frequency discriminator for: receiving the first signal, and providing a second signal based on information from the first signal, the second signal being representative of a gain setting for the phase locked loop to set; wherein the frequency discriminator comprises: a first monostable coupled to a first low pass filter, the first monostable and first filter together receiving the first frequency and providing a first output; a second monostable coupled to a second low pass filter the second monostable and second filter together receiving the second frequency and providing a second output; and a difference amplifier coupled to the first and second monostable and filter combinations for: receiving the first output and the second output; comparing the first output to the second output; and providing the first signal to the comparator which is representative of the difference between the first output and the second output.