Goto Section: 15.32 | 15.35 | Table of Contents
FCC 15.33
Revised as of October 2, 2015
Goto Year:2014 |
2016
§ 15.33 Frequency range of radiated measurements.
(a) For an intentional radiator, the spectrum shall be investigated from the
lowest radio frequency signal generated in the device, without going below 9
kHz, up to at least the frequency shown in this paragraph:
(1) If the intentional radiator operates below 10 GHz: to the tenth harmonic
of the highest fundamental frequency or to 40 GHz, whichever is lower.
(2) If the intentional radiator operates at or above 10 GHz and below 30
GHz: to the fifth harmonic of the highest fundamental frequency or to 100
GHz, whichever is lower.
(3) If the intentional radiator operates at or above 30 GHz: to the fifth
harmonic of the highest fundamental frequency or to 200 GHz, whichever is
lower, unless specified otherwise elsewhere in the rules.
(4) If the intentional radiator contains a digital device, regardless of
whether this digital device controls the functions of the intentional
radiator or the digital device is used for additional control or function
purposes other than to enable the operation of the intentional radiator, the
frequency range shall be investigated up to the range specified in
paragraphs (a)(1) through (a)(3) of this section or the range applicable to
the digital device, as shown in paragraph (b)(1) of this section, whichever
is the higher frequency range of investigation.
(b) For unintentional radiators:
(1) Except as otherwise indicated in paragraphs (b)(2) or (b)(3) of this
section, for an unintentional radiator, including a digital device, the
spectrum shall be investigated from the lowest radio frequency signal
generated or used in the device, without going below the lowest frequency
for which a radiated emission limit is specified, up to the frequency shown
in the following table:
Highest frequency generated or used in the device or on which the device
operates or tunes (MHz) Upper frequency of measurement range (MHz)
Below 1.705 30.
1.705-108 1000.
108-500 2000.
500-1000 5000.
Above 1000 5th harmonic of the highest frequency or 40 GHz, whichever is
lower.
(2) A unintentional radiator, excluding a digital device, in which the
highest frequency generated in the device, the highest frequency used in the
device and the highest frequency on which the device operates or tunes are
less than 30 MHz and which, in accordance with § 15.109, is required to
comply with standards on the level of radiated emissions within the
frequency range 9 kHz to 30 MHz, such as a CB receiver or a device designed
to conduct its radio frequency emissions via connecting wires or cables,
e.g., a carrier current system not intended to radiate, shall be
investigated from the lowest radio frequency generated or used in the
device, without going below 9 kHz (25 MHz for CB receivers), up to the
frequency shown in the following table. If the unintentional radiator
contains a digital device, the upper frequency to be investigated shall be
that shown in the table below or in the table in paragraph (b)(1) of this
section, as based on both the highest frequency generated and the highest
frequency used in the digital device, whichever range is higher.
Highest frequency generated or used in the device or on which the device
operates or tunes (MHz) Upper frequency of measurement range (MHz)
Below 1.705 30
1.705-10 400
10-30 500
(3) Except for a CB receiver, a receiver employing superheterodyne
techniques shall be investigated from 30 MHz up to at least the second
harmonic of the highest local oscillator frequency generated in the device.
If such receiver is controlled by a digital device, the frequency range
shall be investigated up to the higher of the second harmonic of the highest
local oscillator frequency generated in the device or the upper frequency of
the measurement range specified for the digital device in paragraph (b)(1)
of this section.
(c) The above specified frequency ranges of measurements apply to the
measurement of radiated emissions and, in the case of receivers, the
measurement to demonstrate compliance with the antenna conduction limits
specified in § 15.111. The frequency range of measurements for AC power line
conducted limits is specified in § § 15.107 and 15.207 and applies to all
equipment subject to those regulations. In some cases, depending on the
frequency(ies) generated and used by the equipment, only signals conducted
onto the AC power lines are required to be measured.
(d) Particular attention should be paid to harmonics and subharmonics of the
fundamental frequency as well as to those frequencies removed from the
fundamental by multiples of the oscillator frequency. Radiation at the
frequencies of multiplier states should also be checked.
[ 54 FR 17714 , Apr. 25, 1989, as amended at 61 FR 14502 , Apr. 2, 1996; 63 FR 42278 , Aug. 7, 1998]
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Goto Section: 15.32 | 15.35
Goto Year: 2014 |
2016
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