Federal Communications Commission § 2.1049

paragraph (c) of § 2.1049 for the occupied or 1700 Hz (for 3.5 kHz authorized band- bandwidth tests. width), or 1900 Hz (for 4.0 kHz author- (d) Other types of equipment. A curve ized bandwidth), the level of which is or equivalent data which shows that adjusted to produce a radio frequency the equipment will meet the modula- signal component equal in magnitude tion requirements of the rules under to the magnitude of the carrier in this which the equipment is to be licensed. mode. [39 FR 5919, Feb. 15, 1974. Redesignated and (4) As an alternative to paragraphs amended at 63 FR 36599, July 7, 1998] (c) (2) and (3) of this section, other tones besides those specified may be § 2.1049 Measurements required: Occu- used as modulating frequencies, upon a pied bandwidth. sufficient showing of need. However, The occupied bandwidth, that is the any tones so chosen must not be har- frequency bandwidth such that, below monically related, the third and fifth its lower and above its upper frequency order intermodulation products which limits, the mean powers radiated are occur must fall within the ¥25 dB step each equal to 0.5 percent of the total of the emission bandwidth limitation mean power radiated by a given emis- curve, the seventh and ninth order sion shall be measured under the fol- products must fall within the ¥35 dB lowing conditions as applicable: step of the referenced curve and the (a) Radiotelegraph transmitters for eleventh and all higher order products manual operation when keyed at 16 must fall beyond the ¥35 dB step of the dots per second. referenced curve. (b) Other keyed transmitters—when (5) Independent sideband transmit- keyed at the maximum machine speed. ters having two channels—when modu- (c) Radiotelephone transmitters lated by 1700 Hz tones applied simulta- equipped with a device to limit modu- neously to both channels. The input lation or peak envelope power shall be levels of the tones shall be so adjusted modulated as follows. For single side- that the two principal frequency com- band and independent sideband trans- ponents of the radio frequency signal mitters, the input level of the modu- produced are equal in magnitude. lating signal shall be 10 dB greater (d) Radiotelephone transmitters than that necessary to produce rated without a device to limit modulation peak envelope power. or peak envelope power shall be modu- (1) Other than single sideband or lated as follows. For single sideband independent sideband transmitters— and independent sideband transmitters, when modulated by a 2500 Hz tone at an the input level of the modulating sig- input level 16 dB greater than that nec- nal should be that necessary to produce essary to produce 50 percent modula- rated peak envelope power. tion. The input level shall be estab- (1) Other than single sideband or lished at the frequency of maximum re- independent sideband transmitters— sponse of the audio modulating circuit. when modulated by a 2500 Hz tone of (2) Single sideband transmitters in sufficient level to produce at least 85 A3A or A3J emission modes—when percent modulation. If 85 percent mod- modulated by two tones at frequencies ulation is unattainable, the highest of 400 Hz and 1800 Hz (for 3.0 kHz au- percentage modulation shall be used. thorized bandwidth), or 500 Hz and 2100 (2) Single sideband transmitters in Hz (for 3.5 kHz authorized bandwidth), A3A or A3J emission modes—when or 500 Hz and 2400 Hz (for 4.0 kHz au- modulated by two tones at frequencies thorized bandwidth), applied simulta- of 400 Hz and 1800 Hz (for 3.0 kHz au- neously. The input levels of the tones thorized bandwidth), or 500 Hz and 2100 shall be so adjusted that the two prin- Hz (for 3.5 kHz authorized bandwidth), cipal frequency components of the or 500 Hz and 2400 Hz (for 4.0 kHz au- radio frequency signal produced are thorized bandwidth), applied simulta- equal in magnitude. neously. The input levels of the tones (3) Single sideband transmitters in shall be so adjusted that the two prin- the A3H emission mode—when modu- cipal frequency components of the lated by one tone at a frequency of 1500 radio frequency signal produced are Hz (for 3.0 kHz authorized bandwidth), equal in magnitude.

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(3) Single sideband transmitters in simultaneously by a 67 kHz subcarrier the A3H emission mode—when modu- (unmodulated). lated by one tone at a frequency of 1500 (5) FM broadcast transmitter for Hz (for 3.0 kHz authorized bandwidth), stereophonic operation—when modu- or 1700 Hz (for 3.5 kHz authorized band- lated by a 15 kHz input signal to the width), or 1900 Hz (for 4.0 kHz author- main channel, a 15 kHz input signal to ized bandwidth), the level of which is the stereophonic subchannel, and the adjusted to produce a radio frequency pilot subcarrier simultaneously. The signal component equal in magnitude input signals to the main channel and to the magnitude of the carrier in this stereophonic subchannel each shall mode. produce 38 percent modulation of the (4) As an alternative to paragraphs carrier. The pilot subcarrier should (d) (2) and (3) of this section, other produce 9 percent modulation of the tones besides those specified may be carrier. used as modulating frequencies, upon a (6) Television broadcast monaural sufficient showing of need. However transmitters—when modulated 85% by any tones so chosen must not be har- a 15 kHz input signal. monically related, the third and fifth (7) Television broadcast stereophonic order intermodulation products which sound transmitters—when the trans- occur must fall within the ¥25 dB step mitter is modulated with a 15 kHz of the emission bandwidth limitation input signal to the main channel and curve, the seventh and ninth order the stereophonic subchannel, any pilot products must fall within the ¥35 dB subcarrier(s) and any unmodulated step of the referenced curve and the auxiliary subcarrier(s) which may be eleventh and all higher order products provided. The signals to the main chan- must fall beyond the ¥35 dB step of the nel and the stereophonic subchannel referenced curve. must be representative of the system (5) Independent sideband transmit- being tested and when combined with ters having two channels—when modu- any pilot subcarrier(s) or other auxil- lated by 1700 Hz tones applied simulta- iary subcarriers shall result in 85% de- neously to both channels. The input viation of the maximum specified aural levels of the tones shall be so adjusted carrier deviation. that the two principal frequency com- (f) Transmitters for which peak fre- ponents of the radio frequency signal quency deviation (D) is determined in produced are equal in magnitude. accordance with § 2.202(f), and in which (e) Transmitters for use in the Radio the modulating baseband comprises Broadcast Services: more than 3 independent speech chan- (1) AM broadcast transmitters for nels—when modulated by a test signal monaural operation—when amplitude determined in accordance with the fol- modulated 85% by a 7,500 Hz input sig- lowing: nal. (1) A modulation reference level is es- (2) AM broadcast stereophonic oper- tablished for the characteristic ation—when the transmitter operated baseband frequency. (Modulation ref- under any stereophonic modulation erence level is defined as the average condition not exceeding 100% on nega- power level of a sinusoidal test signal tive peaks and tested under the condi- delivered to the modulator input which tions specified in § 73.128 in part 73 of provides the specified value of per- the FCC rules for AM broadcast sta- channel deviation.) tions. (2) Modulation reference level being (3) FM broadcast transmitter not established, the total rms deviation of used for multiplex operation—when the transmitter is measured when a modulated 85 percent by a 15 kHz input test signal consisting of a band of ran- signal. dom noise extending from below 20 kHz (4) FM broadcast transmitters for to the highest frequency in the multiplex operation under Subsidiary baseband, is applied to the modulator Communication Authorization (SCA)— input through any preemphasis net- when carrier is modulated 70 percent works used in normal service. The av- by a 15 kHz main channel input signal, erage power level of the test signal and modulated an additional 15 percent shall exceed the modulation reference

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level by the number of decibels determined using the appropriate formula in the following table:

Number of message circuits that Number of dB by which the average power (Pavg) level test sig- modulate the transmitter nal shall exceed the modulation reference level Limits of Pavg (dBm0)

More than 3, but less than 12 ...... To be specified by the equipment manufacturer subject to FCC approval. At least 12, but less than 60 ...... X+2 log10 Nc ...... X: ¥2 to +2.6 At least 60, but less than 240 ...... X+4 log10 Nc ...... X: ¥5.6 to ¥1.0 240 or more ...... X+10 log10 Nc ...... X: ¥19.6 to ¥15.0

Where X represents the average power in a message circuit in dBm0; Nc is the number of circuits in the multiplexed message load. Pavg shall be selected by the transmitter manufacturer and included with the technical data submitted with the application for type acceptance. (See § 2.202(e) in this chapter.)

(g) Transmitters in which the modu- § 2.1051 Measurements required: Spu- lating baseband comprises not more rious emissions at antenna termi- than three independent channels— nals. when modulated by the full com- The radio frequency voltage or pow- plement of signals for which the trans- ers generated within the equipment mitter is rated. The level of modula- and appearing on a spurious frequency tion for each channel should be set to shall be checked at the equipment out- that prescribed in rule parts applicable put terminals when properly loaded to the services for which the trans- with a suitable artificial antenna. mitter is intended. If specific modula- Curves or equivalent data shall show tion levels are not set forth in the the magnitude of each harmonic and rules, the tests should provide the other spurious emission that can be de- manufacturer’s maximum rated condi- tected when the equipment is operated tion. under the conditions specified in (h) Transmitters employing digital § 2.1049 as appropriate. The magnitude of spurious emissions which are attenu- modulation techniques—when modu- ated more than 20 dB below the permis- lated by an input signal such that its sible value need not be specified. amplitude and symbol rate represent the maximum rated conditions under [39 FR 5919, Feb. 15, 1974. Redesignated and which the equipment will be operated. amended at 63 FR 36599, July 7, 1998] The signal shall be applied through any § 2.1053 Measurements required: Field filter networks, pseudo-random genera- strength of spurious radiation. tors or other devices required in normal service. Additionally, the occupied (a) Measurements shall be made to bandwidth shall be shown for operation detect spurious emissions that may be radiated directly from the cabinet, with any devices used for modifying control circuits, power leads, or inter- the spectrum when such devices are op- mediate circuit elements under normal tional at the discretion of the user. conditions of installation and oper- (i) Transmitters designed for other ation. Curves or equivalent data shall types of modulation—when modulated be supplied showing the magnitude of by an appropriate signal of sufficient each harmonic and other spurious amplitude to be representative of the emission. For this test, single side- type of service in which used. A de- band, independent sideband, and con- scription of the input signal should be trolled carrier transmitters shall be supplied. modulated under the conditions specified in paragraph (c) of § 2.1049, as ap- (Secs. 4, 303, 307, 48 Stat., as amended, 1066, 1082, 1083; 47 U.S.C. 154, 303, 307) propriate. For equipment operating on frequencies below 890 MHz, an open [39 FR 5919, Feb. 15, 1974, as amended at 39 field test is normally required, with FR 35664, Oct. 3, 1974; 47 FR 13164, Mar. 29, the measuring instrument antenna lo- 1982; 48 FR 16493, Apr. 18, 1983; 49 FR 18105, cated in the far-field at all test fre- Apr. 27, 1984. Redesignated at 63 FR 36599, quencies. In the event it is either im- July 7, 1998] practical or impossible to make open

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