47 CFR § 73.1545 - Carrier frequency departure tolerances.
(a) AM stations. The departure of the carrier frequency for monophonic transmissions or center frequency for stereophonic transmissions may not exceed ±20 Hz from the assigned frequency.
(b) FM stations.
(1) The departure of the carrier or center frequency of an FM station with an authorized transmitter output power more than 10 watts may not exceed ±2000 Hz from the assigned frequency.
(2) The departure of the carrier or center frequency of an FM station with an authorized transmitter output power of 10 watts or less may not exceed ±3000 Hz from the assigned frequency.
(c) TV stations.
(1) The departure of the visual carrier frequency of a TV station may not exceed ±1000 Hz from the assigned visual carrier frequency.
(2) The departure of the aural carrier frequency of a TV station may not exceed ±1000 Hz from the actual visual carrier frequency plus exactly 4.5 MHz.
(d) International broadcast stations. The departure of the carrier frequency of an International broadcast station may not exceed 0.0015% of the assigned frequency on which the station is transmitting.
(e) Class A TV stations. The departure of the carrier frequency of Class A TV stations may not exceed the values specified in § 74.761 of this chapter. Provided, however, that Class A TV stations licensed to operate with a carrier offset, including those stations licensed with a maximum effective radiated power and/or antenna height greater than the values specified in their initial Class A TV station authorization, must comply with paragraph (c) of this section.
At a date not later than nine months after release of the Memorandum Opinion and Order on Reconsideration in MM Docket No. 00–10 (the proceeding that established the Class A TV service), all licensed Class A stations must operate with a carrier frequency offset. See Memorandum Opinion and Order on Reconsideration, In the Matter of Establishment of a Class A Television Service, MM Docket No. 00–10, released April 13, 2001.