Sec. 15.107  Conducted limits.

    (a) Except for Class A digital devices, for equipment that is 
designed to be connected to the public utility (AC) power line, the 
radio frequency voltage that is conducted back onto the AC power line on 
any frequency or frequencies within the band 450 kHz to 30 MHz shall not 
exceed 250 microvolts. Compliance with this provision shall be based on 
the measurement of the radio frequency voltage between each power line 
and ground at the power terminals.
    (b) For a Class A digital device that is designed to be connected to 
the public utility (AC) power line, the radio frequency voltage that is 
conducted back onto the AC power line on any frequency or frequencies 
within the band 450 kHz to 30 MHz shall not exceed the limits in the 
following table. Compliance with this provision shall be based on the 
measurement of the radio frequency voltage between each power line and 
ground at the power terminals. The lower limit applies at the band 
edges.

                                                                        
------------------------------------------------------------------------
                                                              Conducted 
                Frequency of emission (MHz)                     limit   
                                                            (microvolts)
------------------------------------------------------------------------
0.45 to 1.705.............................................         1000 
1.705 to 30.0.............................................         3000 
------------------------------------------------------------------------

    (c) The limits shown in paragraphs (a) and (b) of this section shall 
not apply to carrier current systems operating as unintentional 
radiators on frequencies below 30 MHz. In lieu thereof, these carrier 
current systems shall be subject to the following standards:
    (1) For carrier current systems containing their fundamental 
emission within the frequency band 535-1705 kHz and intended to be 
received using a standard AM broadcast receiver: no limit on conducted 
emissions.
    (2) For all other carrier current systems: 1000 uV within the 
frequency band 535-1705 kHz.
    (3) Carrier current systems operating below 30 MHz are also subject 
to the radiated emission limits in Sec. 15.109(e).
    (d) The following option may be employed if the conducted emissions 
exceed the limits in paragraph (a) or (b) of this section, as 
appropriate, when measured using instrumentation employing a quasi-peak 
detector function: if the level of the emission measured using the 
quasi-peak instrumentation is 6 dB, or more, higher than the level of 
the same emission measured with instrumentation having an average 
detector and a 9 kHz minimum bandwidth, that emission is considered 
broadband and the level obtained with the quasi-peak detector may be 
reduced by 13 dB for comparison to the limits. When employing this 
option, the following conditions shall be observed:
    (1) The measuring instrumentation with the average detector shall 
employ a linear IF amplifier.
    (2) Care must be taken not to exceed the dynamic range of the 
measuring instrument when measuring an emission with a low duty cycle.
    (3) The test report required for verification or for an application 
for a grant of equipment authorization shall contain all details 
supporting the use of this option.
    (e) As an alternative to the conducted limits shown in paragraphs 
(a) and (b) of this section, digital devices may be shown to comply with 
the standards contained in the First Edition of International Special 
Committee on Radio Interference (CISPR) Pub. 22 (1985), ``Limits and 
Methods of Measurement of Radio Interference Characteristics of 
Information Technology Equipment,'' and the associated Draft 
International Standards (DISs) adopted in 1992 and published by the 
International Electrotechnical Commission as documents CISPR/G (Central 
Office) 2, CISPR/G (Central Office) 5, CISPR/G (Central Office) 9, 
CISPR/G (Central Office) 11, CISPR/G (Central Office) 12, CISPR/G 
(Central Office) 13, and CISPR/G (Central Office) 14. This incorporation 
by reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of these CISPR 
publications may be purchased from

[[Page 632]]

the American National Standards Institute (ANSI), Sales Department, 11 
West 42nd Street, New York, NY 10036, (212) 642-4900. Copies may also be 
inspected during normal business hours at the following locations: 
Federal Communications Commission, 2025 M Street, NW., Office of 
Engineering and Technology (room 7317), Washington, DC, and Office of 
the Federal Register, 800 N. Capitol Street, NW., suite 700, Washington, 
DC. In addition:
    (1) The test procedure and other requirements specified in this part 
shall continue to apply to digital devices.
    (2) If the conducted emissions are measured to demonstrate 
compliance with the alternative standards in this paragraph, compliance 
must also be demonstrated with the radiated emission limits shown in 
Sec. 15.109(g).
    (f) Measurements to demonstrate compliance with the conducted limits 
are not required for devices which only employ battery power for 
operation and which do not operate from the AC power lines or contain 
provisions for operation while connected to the AC power lines. Devices 
that include, or make provision for, the use of battery chargers which 
permit operating while charging, AC adaptors or battery eliminators or 
that connect to the AC power lines indirectly, obtaining their power 
through another device which is connected to the AC power lines, shall 
be tested to demonstrate compliance with the conducted limits.
[ 54 FR 17714 , Apr. 25, 1989, as amended at  57 FR 33448 , July 29, 1992; 
 58 FR 51249 , Oct. 1, 1993]