§ 95.1775   GMRS modulation requirements.

   Each GMRS transmitter type must be designed to satisfy the modulation
   requirements in this section. Operation of GMRS stations must also be
   in compliance with these requirements.

   (a) Main channels. The peak frequency deviation for emissions to be
   transmitted on the main channels must not exceed ± 5 kHz.

   (b) 462 MHz interstitial channels. The peak frequency deviation for
   emissions to be transmitted on the 462 MHz interstitial channels must
   not exceed ± 5 kHz.

   (c) 467 MHz interstitial channels. The peak frequency deviation for
   emissions to be transmitted on the 467 MHz interstitial channels must
   not exceed ± 2.5 kHz, and the highest audio frequency contributing
   substantially to modulation must not exceed 3.125 kHz.

   (d) Overmodulation. Each GMRS transmitter type, except for a mobile
   station transmitter type with a transmitter power output of 2.5 W or
   less, must automatically prevent a higher than normal audio level from
   causing overmodulation.

   (e) Audio filter. Each GMRS transmitter type must include audio
   frequency low pass filtering, unless it complies with the applicable
   paragraphs of § 95.1779 (without filtering).

   (1) The filter must be between the modulation limiter and the modulated
   stage of the transmitter.

   (2) At any frequency (f in kHz) between 3 and 20 kHz, the filter must
   have an attenuation of at least 60 log (f/3) dB more than the
   attenuation at 1 kHz. Above 20 kHz, it must have an attenuation of at
   least 50 dB more than the attenuation at 1 kHz.

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