Sources of gravity can come in two categories which are not necessarily independent. Static sources would be like planets and stars which have a constant gravitational field which does not change very fast. Variable sources would include masses that are being constantly accelerated over a 'short' period of time. The static sources do not produce gravitational waves, but the variable sources can produce waves whose frequencies depend on how long the mass is being accelerated. There are even high frequency sources such as supernova explosions which produce kilometer-sized gravity waves.
Frequency is just a measure of how rapidly a wave crest passes a reference point in space.
Dr. Sten Odenwald Return to Ask the Astronomer .