47 CFR 74.794 - Digital emissions.

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§ 74.794 Digital emissions.
(a)
(1) An applicant for a digital LPTV or TV translator station construction permit shall specify that the station will be constructed to confine out-of-channel emissions within one of the following emission masks: Simple, stringent or full service.
(2) The power level of emissions on frequencies outside the authorized channel of operation must be attenuated no less than following amounts below the average transmitted power within the authorized 6 MHz channel. In the mask specifications listed in § 74.794(a)(2) and (a)(3), A is the attenuation in dB and Δf is the frequency difference in MHz from the edge of the channel.
(i) Simple mask. At the channel edges, emissions must be attenuated no less than 46 dB. More than 6 MHz from the channel edges, emissions must be attenuated no less than 71 dB. At any frequency between 0 and 6 MHz from the channel edges, emissions must be attenuated no less than the value determined by the following formula:
A (dB) = 46 (Δf2 /1.44)
(ii) Stringent mask. In the first 500 kHz from the channel edges, emissions must be attenuated no less than 47 dB. More than 3 MHz from the channel edges, emissions must be attenuated no less than 76 dB. At any frequency between 0.5 and 3 MHz from the channel edges, emissions must be attenuated no less than the value determined by the following formula:
A(dB) = 47 11.5 (Δf-0.5)
(iii) Full service mask:
(A) The power level of emissions on frequencies outside the authorized channel of operation must be attenuated no less than the following amounts below the average transmitted power within the authorized channel. In the first 500 kHz from the channel edge the emissions must be attenuated no less than 47 dB. More than 6 MHz from the channel edge, emissions must be attenuated no less than 110 dB. At any frequency between 0.5 and 6 MHz from the channel edge, emissions must be attenuated no less than the value determined by the following formula:
Attenuation in dB = −11.5([Delta]f 3.6);
Where:
[Delta] f = frequency difference in MHz from the edge of the channel.
(B) This attenuation is based on a measurement bandwidth of 500 kHz. Other measurement bandwidths may be used as long as appropriate correction factors are applied. Measurements need not be made any closer to the band edge than one half of the resolution bandwidth of the measuring instrument. Emissions include sidebands, spurious emissions and radio frequency harmonics. Attenuation is to be measured at the output terminals of the transmitter (including any filters that may be employed). In the event of interference caused to any service, greater attenuation may be required.
(3) The attenuation values for the simple and stringent emission masks are based on a measurement bandwidth of 500 kHz. Other measurement bandwidths may be used and converted to the reference 500 kHz value by the following formula:
A(dB) = Aalternate 10 log (BWalternate / 500)
where A(dB) is the measured or calculated attenuation value for the reference 500 kHz bandwidth, and Aalternate is the measured or calculated attenuation for a bandwidth BWalternate. Emissions include sidebands, spurious emissions and radio harmonics. Attenuation is to be measured at the output terminals of the transmitter (including any filters that may be employed). In the event of interference caused to any service by out-of-channel emissions, greater attenuation may be required.
(b) In addition to meeting the emission attenuation requirements of the simple or stringent mask (including attenuation of radio frequency harmonics), digital low power TV and TV translator stations authorized to operate on TV channels 22-24, (518-536 MHz), 32-36 (578-608 MHz), 38 (614-620 MHz), and 65-69 (776-806 MHz) must provide specific “out of band” protection to Radio Navigation Satellite Services in the bands: L5 (1164-1215 MHz); L2 (1215-1240 MHz) and L1 (1559-1610 MHz).
(1) An FCC-certificated transmitter specifically certified for use on one or more of the above channels must include filtering with an attenuation of not less than 85 dB in the GPS bands, which will have the effect of reducing harmonics in the GPS bands from what is produced by the digital transmitter, and this attenuation must be demonstrated as part of the certification application to the Commission.
(2) For an installation on one of the above channels with a digital transmitter not specifically FCC-certificated for the channel, a low pass filter or equivalent device rated by its manufacturer to have an attenuation of at least 85 dB in the GPS bands, which will have the effect of reducing harmonics in the GPS bands from what is produced by the digital transmitter, and must be installed in a manner that will prevent the harmonic emission content from reaching the antenna. A description of the low pass filter or equivalent device with the manufacturer's rating or a report of measurements by a qualified individual shall be retained with the station license. Field measurements of the second or third harmonic output of a transmitter so equipped are not required.
[69 FR 69336, Nov. 29, 2004, as amended at 76 FR 44828, July 27, 2011]

Title 47 published on 2013-10-01

The following are only the Rules published in the Federal Register after the published date of Title 47.

For a complete list of all Rules, Proposed Rules, and Notices view the Rulemaking tab.

  • 2014-08-15; vol. 79 # 158 - Friday, August 15, 2014
    1. 79 FR 48442 - Expanding the Economic and Innovation Opportunities of Spectrum Through Incentive Auctions
      GPO FDSys XML | Text
      FEDERAL COMMUNICATIONS COMMISSION
      Final rule.
      Effective October 14, 2014 except for amendments to §§ 1.2105(a)(2)(xii) and (c)(6); 1.2204(a), (c), (d)(3), and (d)(5); 1.2205(c) and (d); 1.2209; 2.1033(c)(19)(iii); 15.713(b)(2)(iv); 15.713(h)(10); 27.14(k) and (t)(6); 27.17(c); 27.19(b) and (c); 73.3700(b)(1)(i) through (v), (b)(2)(i) and (ii), (b)(3), (b)(4)(i) and (ii), and (b)(5); 73.3700(c); 73.3700(d); 73.3700(e)(2) through (6); 73.3700(f); 73.3700(g); 73.3700(h)(4) and (6); 74.602(h)(5)(ii) and (iii); and 74.802(b)(2), which contain new or modified information collection requirements that are not effective until approved by the Office of Management and Budget. The Federal Communications Commission will publish a document in the Federal Register announcing the effective date for those sections.
      47 CFR Parts 0, 1, 2, 15, 27, 73, and 74

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United States Code

Title 47 published on 2013-10-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 47 CFR 74 after this date.

  • 2014-08-15; vol. 79 # 158 - Friday, August 15, 2014
    1. 79 FR 48442 - Expanding the Economic and Innovation Opportunities of Spectrum Through Incentive Auctions
      GPO FDSys XML | Text
      FEDERAL COMMUNICATIONS COMMISSION
      Final rule.
      Effective October 14, 2014 except for amendments to §§ 1.2105(a)(2)(xii) and (c)(6); 1.2204(a), (c), (d)(3), and (d)(5); 1.2205(c) and (d); 1.2209; 2.1033(c)(19)(iii); 15.713(b)(2)(iv); 15.713(h)(10); 27.14(k) and (t)(6); 27.17(c); 27.19(b) and (c); 73.3700(b)(1)(i) through (v), (b)(2)(i) and (ii), (b)(3), (b)(4)(i) and (ii), and (b)(5); 73.3700(c); 73.3700(d); 73.3700(e)(2) through (6); 73.3700(f); 73.3700(g); 73.3700(h)(4) and (6); 74.602(h)(5)(ii) and (iii); and 74.802(b)(2), which contain new or modified information collection requirements that are not effective until approved by the Office of Management and Budget. The Federal Communications Commission will publish a document in the Federal Register announcing the effective date for those sections.
      47 CFR Parts 0, 1, 2, 15, 27, 73, and 74