§ 78.103   Emissions and emission limitations.

   (a) A CARS station may be authorized to employ any type of emission,
   for which there are technical standards incorporated in Subpart D of
   this part, suitable for the simultaneous transmission of visual and
   aural television signals.

   (b) Any emission appearing on a frequency outside of the channel
   authorized for a transmitter shall be attenuated below the power of the
   emission in accordance with the following schedule:

   (1) For stations using FM or double sideband AM transmission:

   (i) On any frequency above the upper channel limit or below the lower
   channel limit by between zero and 50 percent of the authorized channel
   width: At least 25 decibels below the mean power of the emission;

   (ii) On any frequency above the upper channel limit or below the lower
   channel limit by more than 50 percent and up to 150 percent of the
   authorized channel width: At least 35 decibels below the mean power of
   the emission; and

   (iii) On any frequency above the upper channel limit or below the lower
   channel limit by more than 150 percent of the authorized channel width:
   At least 43+10 log10 (power in watts) decibels below the mean power of
   the emission.

   (2) For CARS stations using vestigial sideband AM transmission: At
   least 50 decibels below the peak power of the emission.

   (c) For operation in the 17.7.7-19.7 GHz band:

   The mean power of any emission shall be attenuated below the mean
   output power of the transmitter in accordance with the following
   schedule:

   (1) When using frequency modulation:

   (i) On any frequency removed from the assigned (center) frequency by
   more than 50% up to and including 100% of the authorized bandwidth: At
   least 25 dB;

   (ii) On any frequency removed from the assigned (center) frequency by
   more than 100% up to and including 250% of the authorized bandwidth: At
   least 35 dB;

   (iii) On any frequency removed from the assigned (center) frequency by
   more than 250% of the authorized bandwidth: At least 43+10 log 10 (mean
   output power in watts) dB, or 80 dB, whichever is the lesser
   attenuation.

   (2) When using digital modulation:

   (i) In any 1 MHz band, the center frequency of which is removed from
   the assigned frequency by more than 50% up to and including 250% of the
   authorized bandwidth: As specified by the following equation but in no
   event less than 11 dB.

   A = 11 + 0.4 (P - 50) + 10 log10 B

   where:

   A=Attenuation (in dB) below the mean output power level.

   P=Percent removed from the carrier frequency.

   B=Authorized bandwidth in MHz.

   [Attenuation greater than 56 decibels is not required.]

   (ii) In any 4 kHz band, the center frequency of which is removed from
   the assigned frequency by more than 250% of the authorized bandwidth:
   At least 43=10 log10 (mean output power in watts) dB, or 80 dB,
   whichever is the lesser attenuation.

   (3) Amplitude Modulation:

   For vestigial sideband AM video: On any frequency removed from the
   center frequency of the authorized band by more than 50%: at least 50
   dB below peak power of the emission.

   (d) In the event that interference to other stations is caused by
   emissions outside the authorized channel, the Commission may require
   greater attenuation than that specified in paragraph (b) of this
   section.

   (e) The maximum bandwidth that will be authorized per frequency
   assignment is set out in the table that follows. Regardless of the
   maximum authorized bandwidth specified for each frequency band, the
   Commission reserves the right to issue a license for less than the
   maximum bandwidth if it appears that a bandwidth less than the maximum
   would be sufficient to support an applicant's intended communications.
   Frequency band (MHz) Maximum authorized band-width (MHz)
   1,990 to 2,110       17 or 18.^1
   6,425 to 6,525       8 or 25.
   6,875 to 7,125       25.
   12,700 to 13,250     25.
   17,700 to 19,700     80.

   ^1After a licensee has been relocated in accordance with § 78.40, the
   maximum authorized bandwidth in the frequency band 2025 to 2010 MHz
   will be 12 megahertz.

   [ 37 FR 3292 , Feb. 12, 1972, as amended at  37 FR 15927 , Aug. 8, 1972;  38 FR 16648 , June 25, 1973;  39 FR 26025 , July 16, 1974;  48 FR 50736 , Nov.
   3, 1983;  49 FR 37779 , Sept. 26, 1984;  52 FR 7145 , Mar. 9, 1987;  65 FR 48182 , Aug. 7, 2000;  68 FR 12776 , Mar. 17, 2003;  68 FR 68253 , Dec. 8,
   2003]

   return arrow Back to Top