Goto Section: 17.33 | 17.37 | Table of Contents
FCC 17.35
Revised as of October 1, 2011
Goto Year:2010 |
2012
§ 15.35 Measurement detector functions and bandwidths.
The conducted and radiated emission limits shown in this part are based
on the following, unless otherwise specified elsewhere in this part:
(a) On any frequency or frequencies below or equal to 1000 MHz, the
limits shown are based on measuring equipment employing a CISPR
quasi-peak detector function and related measurement bandwidths, unless
otherwise specified. The specifications for the measuring instrument
using the CISPR quasi-peak detector can be found in Publication 16 of
the International Special Committee on Radio Interference (CISPR) of
the International Electrotechnical Commission. As an alternative to
CISPR quasi-peak measurements, the responsible party, at its option,
may demonstrate compliance with the emission limits using measuring
equipment employing a peak detector function, properly adjusted for
such factors as pulse desensitization, as long as the same bandwidths
as indicated for CISPR quasi-peak measurements are employed.
Note: For pulse modulated devices with a pulse-repetition frequency of
20 Hz or less and for which CISPR quasi-peak measurements are
specified, compliance with the regulations shall be demonstrated using
measuring equipment employing a peak detector function, properly
adjusted for such factors as pulse desensitization, using the same
measurement bandwidths that are indicated for CISPR quasi-peak
measurements.
(b) Unless otherwise specified, on any frequency or frequencies above
1000 MHz, the radiated emission limits are based on the use of
measurement instrumentation employing an average detector function.
Unless otherwise specified, measurements above 1000 MHz shall be
performed using a minimum resolution bandwidth of 1 MHz. When average
radiated emission measurements are specified in this part, including
average emission measurements below 1000 MHz, there also is a limit on
the peak level of the radio frequency emissions. Unless otherwise
specified, e.g. , see § § 15.250, 15.252, 15.255, and 15.509-15.519,
the limit on peak radio frequency emissions is 20 dB above the maximum
permitted average emission limit applicable to the equipment under
test. This peak limit applies to the total peak emission level radiated
by the device, e.g. , the total peak power level. Note that the use of
a pulse desensitization correction factor may be needed to determine
the total peak emission level. The instruction manual or application
note for the measurement instrument should be consulted for determining
pulse desensitization factors, as necessary.
(c) Unless otherwise specified, e.g. § 15.255(b), when the radiated
emission limits are expressed in terms of the average value of the
emission, and pulsed operation is employed, the measurement field
strength shall be determined by averaging over one complete pulse
train, including blanking intervals, as long as the pulse train does
not exceed 0.1 seconds. As an alternative (provided the transmitter
operates for longer than 0.1 seconds) or in cases where the pulse train
exceeds 0.1 seconds, the measured field strength shall be determined
from the average absolute voltage during a 0.1 second interval during
which the field strength is at its maximum value. The exact method of
calculating the average field strength shall be submitted with any
application for certification or shall be retained in the measurement
data file for equipment subject to notification or verification.
[ 54 FR 17714 , Apr. 25, 1989, as amended at 56 FR 13083 , Mar. 29, 1991;
61 FR 14502 , Apr. 2, 1996; 63 FR 42279 , Aug. 7, 1998; 67 FR 34855 , May
16, 2002; 70 FR 6773 , Feb. 9, 2005]
Goto Section: 17.33 | 17.37
Goto Year: 2010 |
2012
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