Sec.  90.210   Emission masks.

   Link to an amendment published at  72 FR 35195 , June 27, 2007.

   Except as indicated elsewhere in this part, transmitters used in the radio
   services governed by this part must comply with the emission masks outlined
   in this section. Unless otherwise stated, per paragraphs (d)(4), (e)(4), and
   (m) of this section, measurements of emission power can be expressed in
   either peak or average values provided that emission powers are expressed
   with the same parameters used to specify the unmodulated transmitter carrier
   power.  For  transmitters that do not produce a full power unmodulated
   carrier, reference to the unmodulated transmitter carrier power refers to
   the  total  power contained in the channel bandwidth. Unless indicated
   elsewhere in this part, the table in this section specifies the emission
   masks for equipment operating in the frequency bands governed under this
   part.

   Applicable Emission Masks
   Frequency band
   (MHz) Mask for equipment with Audio low pass
   filter Mask for equipment without audio low pass filter
          Below 25^1                                      A or B     A or C
          25–50                                           B          C
          72–76                                           B          C
          150–174^2                                       B, D, or E C, D, or E
          150 Paging-only                                 B          C
          220–222                                         F          F
          421–512^2                                       B, D, or E C, D, or E
          450 Paging-only                                 B          G
          806–809/851–854                                 B          H
          809–824/854–869^3                               B          G
          896–901/935–940                                 I          J
          902–928                                         K          K
          929–930                                         B          G
          4940–4990 MHz                                   L or M     L or M.
          5850–5925^4                                               
          All other bands                                 B          C

   ^1Equipment using single sideband J3E emission must the requirements of
   Emission Mask A. Equipment using other emissions must meet the requirements
   of Emission Mask B or C, as applicable.

   ^2Equipment designed to operate with a 25 kHz channel bandwidth must meet
   the requirements of Emission Mask B or C, as applicable. Equipment designed
   to operate with a 12.5 kHz channel bandwidth must meet the requirements of
   Emission Mask D, and equipment designed to operate with a 6.25 kHz channel
   bandwidth Must meet the requirements of Emission Mask E.

   ^3Equipment used in this licensed to EA or non-EA systems shall comply with
   the emission mask provisions of  Sec. 90.691.

   ^4DSRCS Roadside Units equipment in the 5850–5925 MHz band is governed under
   subpart M of this part.

   (a) Emission Mask A. For transmitters utilizing J3E emission, the carrier
   must  be at least 40 dB below the peak envelope power and the power of
   emissions  must  be reduced below the output power (P in watts) of the
   transmitter as follows:

   (1) On any frequency removed from the assigned frequency by more than 50
   percent, but not more than 150 percent of the authorized bandwidth: At least
   25 dB.

   (2) On any frequency removed from the assigned frequency by more than 150
   percent, but not more than 250 percent of the authorized bandwidth: At least
   35 dB.

   (3) On any frequency removed from the assigned frequency by more than 250
   percent of the authorized bandwidth: At least 43 + 10 log P dB.

   (b)  Emission Mask B. For transmitters that are equipped with an audio
   low-pass filter, the power of any emission must be attenuated below the
   unmodulated carrier power (P) as follows:

   (1) On any frequency removed from the assigned frequency by more than 50
   percent, but not more than 100 percent of the authorized bandwidth: At least
   25 dB.

   (2) On any frequency removed from the assigned frequency by more than 100
   percent, but not more than 250 percent of the authorized bandwidth: At least
   35 dB.

   (3) On any frequency removed from the assigned frequency by more than 250
   percent of the authorized bandwidth: At least 43 + 10 log (P) dB.

   (c) Emission Mask C. For transmitters that are not equipped with an audio
   low-pass filter, the power of any emission must be attenuated below the
   unmodulated carrier output power (P) as follows:

   (1) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 5 kHz, but not more than
   10 kHz: At least 83 log (f[d]/5) dB;

   (2) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 10 kHz, but not more than
   250 percent of the authorized bandwidth: At least 29 log (f[d]^2 /11) dB or
   50 dB, whichever is the lesser attenuation;

   (3) On any frequency removed from the center of the authorized bandwidth by
   more than 250 percent of the authorized bandwidth: At least 43 + 10 log (P)
   dB.

   (d) Emission Mask D—12.5 kHz channel bandwidth equipment. For transmitters
   designed to operate with a 12.5 kHz channel bandwidth, any emission must be
   attenuated below the power (P) of the highest emission contained within the
   authorized bandwidth as follows:

   (1) On any frequency from the center of the authorized bandwidth f[0]to
   5.625 kHz removed from f[0]: Zero dB.

   (2) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 5.625 kHz but no more
   than 12.5 kHz: At least 7.27(f[d]−2.88 kHz) dB.

   (3) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 12.5 kHz: At least 50 +
   10 log (P) dB or 70 dB, whichever is the lesser attenuation.

   (4) The reference level for showing compliance with the emission mask shall
   be established using a resolution bandwidth sufficiently wide (usually two
   to three times the channel bandwidth) to capture the true peak emission of
   the equipment under test. In order to show compliance with the emissions
   mask up to and including 50 kHz removed from the edge of the authorized
   bandwidth, adjust the resolution bandwidth to 100 Hz with the measuring
   instrument  in a peak hold mode. A sufficient number of sweeps must be
   measured  to  insure  that the emission profile is developed. If video
   filtering  is used, its bandwidth must not be less than the instrument
   resolution bandwidth. For emissions beyond 50 kHz from the edge of the
   authorized bandwidth, see paragraph (m) of this section. If it can be shown
   that use of the above instrumentation settings do not accurately represent
   the  true  interference potential of the equipment under test, then an
   alternate  procedure may be used provided prior Commission approval is
   obtained.

   (e)  Emission Mask E—6.25 kHz or less channel bandwidth equipment. For
   transmitters designed to operate with a 6.25 kHz or less bandwidth, any
   emission must be attenuated below the power (P) of the highest emission
   contained within the authorized bandwidth as follows:

   (1) On any frequency from the center of the authorized bandwidth f[0]to 3.0
   kHz removed from f[0]: Zero dB.

   (2) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 3.0 kHz but no more than
   4.6  kHz: At least 30 + 16.67(f[d]−3 kHz) or 55 + 10 log (P) or 65 dB,
   whichever is the lesser attenuation.

   (3) On any frequency removed from the center of the authorized bandwidth by
   more than 4.6 kHz: At least 55 + 10 log (P) or 65 dB, whichever is the
   lesser attenuation.

   (4) The reference level for showing compliance with the emission mask shall
   be established using a resolution bandwidth sufficiently wide (usually two
   to three times the channel bandwidth) to capture the true peak emission of
   the equipment under test. In order to show compliance with the emissions
   mask up to and including 50 kHz removed from the edge of the authorized
   bandwidth, adjust the resolution bandwidth to 100 Hz with the measuring
   instrument  in a peak hold mode. A sufficient number of sweeps must be
   measured  to  insure  that the emission profile is developed. If video
   filtering  is used, its bandwidth must not be less than the instrument
   resolution bandwidth. For emissions beyond 50 kHz from the edge of the
   authorized bandwidth, see paragraph (m) of this section. If it can be shown
   that use of the above instrumentation settings do not accurately represent
   the  true  interference potential of the equipment under test, then an
   alternate  procedure may be used provided prior Commission approval is
   obtained.

   (f) Emission Mask F. For transmitters operating in the 220–222 MHz frequency
   band, any emission must be attenuated below the power (P) of the highest
   emission contained within the authorized bandwidth as follows:

   (1) On any frequency from the center of the authorized bandwidth f[o]to the
   edge of the authorized bandwidth f[e]: Zero dB.

   (2) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 2 kHz up to and including
   3.75 kHz: 30 + 20(f[d]-2) dB or 55 + 10 log (P), or 65 dB, whichever is the
   lesser attenuation.

   (3)  On  any  frequency beyond 3.75 kHz removed from the center of the
   authorized bandwidth fd:At least 55 + 10 log (P) dB.

   (g) Emission Mask G. For transmitters that are not equipped with an audio
   low-pass filter, the power of any emission must be attenuated below the
   unmodulated carrier power (P) as follows:

   (1) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 10 kHz, but no more than
   250 percent of the authorized bandwidth: At least 116 log (f[d]/6.1) dB, or
   50 + 10 log (P) dB, or 70 dB, whichever is the lesser attenuation;

   (2) On any frequency removed from the center of the authorized bandwidth by
   more than 250 percent of the authorized bandwidth: At least 43 + 10 log (P)
   dB.

   (h) Emission Mask H. For transmitters that are not equipped with an audio
   low-pass filter, the power of any emission must be attenuated below the
   unmodulated carrier power (P) as follows:

   (1) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of 4 kHz or less: Zero dB.

   (2) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 4 kHz, but no more than
   8.5 kHz: At least 107 log (f[d]/4) dB;

   (3) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 8.5 kHz, but no more than
   15 kHz: At least 40.5 log (f[d]/1.16) dB;

   (4) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 15 kHz, but no more than
   25 kHz: At least 116 log (f[d]/6.1) dB;

   (5) On any frequency removed from the center of the authorized bandwidth by
   more than 25 kHz: At least 43 + log (P) dB.

   (i) Emission Mask I. For transmitters that are equipped with an audio low
   pass  filter,  the  power of any emission must be attenuated below the
   unmodulated carrier power of the transmitter (P) as follows:

   (1) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency of more than 6.8 kHz, but no more than 9.0 kHz: At
   least 25 dB;

   (2) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency of more than 9.0 kHz, but no more than 15 kHz: At
   least 35 dB;

   (3) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency of more than 15 kHz: At least 43 + 10 log (P) dB,
   or 70 dB, whichever is the lesser attenuation.

   (j) Emission Mask J. For transmitters that are not equipped with an audio
   low-pass filter, the power of any emission must be attenuated below the
   unmodulated carrier power of the transmitter (P) as follows:

   (1) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 2.5 kHz, but no more than
   6.25 kHz: At least 53 log (f[d]/2.5) dB;

   (2) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 6.25 kHz, but no more
   than 9.5 kHz: At least 103 log (f[d]/3.9) dB;

   (3) On any frequency removed from the center of the authorized bandwidth by
   a displacement frequency (f[d]in kHz) of more than 9.5 kHz: At least 157 log
   (f[d]/5.3) dB, or 50 + 10 log (P) dB or 70 dB, whichever is the lesser
   attenuation.

   (k)  Emission  Mask  K —(1) Wideband multilateration transmitters. For
   transmitters authorized under subpart M to provide forward or reverse links
   in a multilateration system in the subbands 904–909.75 MHz, 921.75–927.25
   MHz and 919.75–921.75 MHz, and which transmit an emission occupying more
   than 50 kHz bandwidth: in any 100 kHz band, the center frequency of which is
   removed from the center of authorized sub-band(s) by more than 50 percent of
   the authorized bandwidth, the power of emissions shall be attenuated below
   the transmitter output power, as specified by the following equation, but in
   no case less than 31 dB:

   A=16+0.4 (D−50)+10 log B (attenuation greater than 66 dB is not required)

   Where:

   A = attenuation (in decibels) below the maximum permitted output power level

   D = displacement of the center frequency of the measurement bandwidth from
   the center frequency of the authorized sub-band, expressed as a percentage
   of the authorized bandwidth B

   B = authorized bandwidth in megahertz.

   (2) Narrowband forward link transmitters. For LMS multilateration narrowband
   forward link transmitters operating in the 927.25–928 MHz frequency band the
   power of any emission shall be attenuated below the transmitter output power
   (P) in accordance with following schedule:

   On any frequency outside the authorized sub-band and removed from the edge
   of the authorized sub-band by a displacement frequency (f[d]in kHz): at
   least 116 log ((f[d]+10)/6.1) dB or 50 + 10 log (P) dB or 70 dB, whichever
   is the lesser attenuation.

   (3) Other transmitters . For all other transmitters authorized under subpart
   M that operate in the 902–928 MHz band, the peak power of any emission shall
   be attenuated below the power of the highest emission contained within the
   licensee's sub-band in accordance with the following schedule:

   (i) On any frequency within the authorized bandwidth: Zero dB.

   (ii) On any frequency outside the licensee's sub-band edges: 55 + 10 log(P)
   dB, where (P) is the highest emission (watts) of the transmitter inside the
   licensee's sub-band.

   (4) In the 902–928 MHz band, the resolution bandwidth of the instrumentation
   used to measure the emission power shall be 100 kHz, except that, in regard
   to paragraph (2) of this section, a minimum spectrum analyzer resolution
   bandwidth of 300 Hz shall be used for measurement center frequencies with 1
   MHz of the edge of the authorized subband. The video filter bandwidth shall
   not be less than the resolution bandwidth.

   (5) Emission power shall be measured in peak values.

   (6)  The  LMS sub-band edges for non-multilateration systems for which
   emissions must be attenuated are 902.00, 904.00, 909.5 and 921.75 MHz.

   (l) Emission Mask L. For low power transmitters (20 dBm or less) operating
   in the 4940–4990 MHz frequency band, the power spectral density of the
   emissions must be attenuated below the output power of the transmitter as
   follows:

   (1) On any frequency removed from the assigned frequency between 0–45% of
   the authorized bandwidth (BW): 0 dB.

   (2) On any frequency removed from the assigned frequency between 45–50% of
   the authorized bandwidth: 219 log (% of (BW)/45) dB.

   (3) On any frequency removed from the assigned frequency between 50–55% of
   the authorized bandwidth: 10 + 242 log (% of (BW)/50) dB.

   (4) On any frequency removed from the assigned frequency between 55–100% of
   the authorized bandwidth: 20 + 31 log (% of (BW)/55) dB attenuation.

   (5) On any frequency removed from the assigned frequency between 100–150% of
   the authorized bandwidth: 28 + 68 log (% of (BW)/100) dB attenuation.

   (6) On any frequency removed from the assigned frequency above 150% of the
   authorized bandwidth: 40 dB.

   (7) The zero dB reference is measured relative to the highest average power
   of the fundamental emission measured across the designated channel bandwidth
   using  a  resolution bandwidth of at least one percent of the occupied
   bandwidth of the fundamental emission and a video bandwidth of 30 kHz. The
   power spectral density is the power measured within the resolution bandwidth
   of  the  measurement device divided by the resolution bandwidth of the
   measurement device. Emission levels are also based on the use of measurement
   instrumentation employing a resolution bandwidth of at least one percent of
   the occupied bandwidth.

   (m) Emission Mask M. For high power transmitters (greater that 20 dBm)
   operating in the 4940–4990 MHz frequency band, the power spectral density of
   the emissions must be attenuated below the output power of the transmitter
   as follows:

   (1) On any frequency removed from the assigned frequency between 0–45% of
   the authorized bandwidth (BW): 0 dB.

   (2) On any frequency removed from the assigned frequency between 45–50% of
   the authorized bandwidth: 568 log (% of (BW)/45) dB.

   (3) On any frequency removed from the assigned frequency between 50–55% of
   the authorized bandwidth: 26 + 145 log (% of BW/50) dB.

   (4) On any frequency removed from the assigned frequency between 55–100% of
   the authorized bandwidth: 32 + 31 log (% of (BW)/55) dB.

   (5) On any frequency removed from the assigned frequency between 100–150% of
   the authorized bandwidth: 40 + 57 log (% of (BW)/100) dB.

   (6) On any frequency removed from the assigned frequency between above 150%
   of the authorized bandwidth: 50 dB or 55 + 10 log (P) dB, whichever is the
   lesser attenuation.

   (7) The zero dB reference is measured relative to the highest average power
   of the fundamental emission measured across the designated channel bandwidth
   using  a  resolution bandwidth of at least one percent of the occupied
   bandwidth of the fundamental emission and a video bandwidth of 30 kHz. The
   power spectral density is the power measured within the resolution bandwidth
   of  the  measurement device divided by the resolution bandwidth of the
   measurement device. Emission levels are also based on the use of measurement
   instrumentation employing a resolution bandwidth of at least one percent of
   the occupied bandwidth.

   Note  to paragraph(m): Low power devices may as an option, comply with
   paragraph (m).

   (n) Other frequency bands. Transmitters designed for operation under this
   part on frequencies other than listed in this section must meet the emission
   mask requirements of Emission Mask B. Equipment operating under this part on
   frequencies allocated to but shared with the Federal Government, must meet
   the applicable Federal Government technical standards.

   (o) Instrumentation. The reference level for showing compliance with the
   emission mask shall be established, except as indicated in  Sec.  Sec. 90.210 (d),
   (e),  and (k), using standard engineering practices for the modulation
   characteristic used by the equipment under test. When measuring emissions in
   the 150–174 MHz and 421–512 MHz bands the following procedures will apply. A
   sufficient number of sweeps must be measured to insure that the emission
   profile is developed. If video filtering is used, its bandwidth must not be
   less than the instrument resolution bandwidth. For frequencies more than 50
   kHz removed from the edge of the authorized bandwidth a resolution of at
   least 100 kHz must be used for frequencies below 1000 MHz. Above 1000 MHz
   the resolution bandwidth of the instrumentation must be at least 1 MHz. If
   it  can be shown that use of the above instrumentation settings do not
   accurately represent the true interference potential of the equipment under
   test, then an alternate procedure may be used provided prior Commission
   approval is obtained.

   [ 60 FR 37264 , July 19, 1995, as amended at  61 FR 4235 , Feb. 5, 1996;  61 FR 6155 , Feb. 16, 1996;  61 FR 18986 , Apr. 30, 1996;  62 FR 41214 , July 31, 1997;
    62 FR 52044 , Oct. 6, 1997;  64 FR 66409 , Nov. 26, 1999;  67 FR 63288 , Oct. 11,
   2002;  68 FR 38639 , June 30, 2003;  69 FR 46443 , Aug. 3, 2004;  69 FR 67838 ,
   Nov. 22, 2004;  70 FR 28466 , May 18, 2005;  70 FR 61061 , Oct. 20, 2005;  72 FR 35195 , June 27, 2007]