FREQUENCY TOLERANCE

The maximum permissible departure by the center frequency of the frequency band occupied by an emission from the assigned frequency , or by the characteristic frequency of an emission from the reference frequency . Frequency tolerance is expressed in parts per 10 6 or in hertz . [ NTIA ] [ RR ] ( 188 ) Note: In the United States, frequency tolerance is expressed in parts per 10 n , in hertz, or in percentages. Frequency tolerance includes both the initial setting tolerance and excursions related to short- and long-term instability and aging.