[Code of Federal Regulations]
[Title 47, Volume 5, Parts 80 to End]
[Revised as of October 1, 1999]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR97.311]
[Page 581-582]
TITLE 47--TELECOMMUNICATION
PART 97--AMATEUR RADIO SERVICE--Table of Contents
Subpart D--Technical Standards
Sec. 97.311 SS emission types.
(a) SS emission transmissions by an amateur station are authorized
only for communications between points within areas where the amateur
service is regulated by the FCC and between an area where the amateur
service is regulated by the FCC and an amateur station in another
country that permits such communications. SS emission transmissions must
not be used for the purpose of obscuring the meaning of any
communication.
(b) A station transmitting SS emissions must not cause harmful
interference to stations employing other authorized emissions, and must
accept all interference caused by stations employing other authorized
emissions.
(c) When deemed necessary by a District Director to assure
compliance with this part, a station licensee must:
(1) Cease SS emission transmissions;
(2) Restrict SS emission transmissions to the extent instructed; and
(3) Maintain a record, convertible to the original information
(voice, text, image, etc.) of all spread spectrum communications
transmitted.
(d) The transmitter power must not exceed 100 W under any
circumstances. If more than 1 W is used, automatic transmitter control
shall limit output power to that which is required for the
communication. This shall be determined by the use of the ratio,
measured at the receiver, of the received energy per user data bit (Eb)
to the sum of the received power spectral densities of noise
(N<INF>0</INF>) and co-channel interference (I<INF>0</INF>). Average
transmitter power
[[Page 582]]
over 1 W shall be automatically adjusted to maintain an Eb/
(N<INF>0</INF> + I<INF>0</INF>) ratio of no more than 23 dB at the
intended receiver.
[64 FR 51471, Sept. 23, 1999]
Effective Date Note: At 64 FR 51471, Sept. 23, 1999, Sec. 97.311 was
revised, effective Nov. 1, 1999. For the convenience of the user, the
superseded text is set forth as follows:
Sec. 97.311 SS emission types.
(a) SS emission transmissions by an amateur station are authorized
only for communications between points within areas where the amateur
service is regulated by the FCC. SS emission transmissions must not be
used for the purpose of obscuring the meaning of any communication.
(b) Stations transmitting SS emission must not cause harmful
interference to stations employing other authorized emissions, and must
accept all interference caused by stations employing other authorized
emissions. For the purposes of this paragraph, unintended triggering of
carrier operated repeaters is not considered to be harmful interference.
(c) Only the following types of SS emission transmissions are
authorized (hybrid SS emissions transmissions involving both spreading
techniques are prohibited):
(1) Frequency hopping where the carrier of the transmitted signal is
modulated with unciphered information and changes frequency at fixed
intervals under the direction of a high speed code sequence.
(2) Direct sequence where the information is modulo-2 added to a
high speed code sequence. The combined information and code are then
used to modulate the RF carrier. The high speed code sequence dominates
the modulation function, and is the direct cause of the wide spreading
of the transmitted signal.
(d) The only spreading sequences that are authorized are from the
output of one binary linear feedback shift register (which may be
implemented in hardware or software).
(1) Only the following sets of connections may be used:
------------------------------------------------------------------------
Number of stages in shift register Taps used in feedback
------------------------------------------------------------------------
7...................................... 7,1.
13..................................... 13,4, 3, and 1.
19..................................... 19, 5, 2, and 1.
------------------------------------------------------------------------
(2) The shift register must not be reset other than by its feedback
during an individual transmission. The shift register output sequence
must be used without alteration.
(3) The output of the last stage of the binary linear feedback shift
register must be used as follows:
(i) For frequency hopping transmissions using x frequencies, n
consecutive bits from the shift register must be used to select the next
frequency from a list of frequencies sorted in ascending order. Each
consecutive frequency must be selected by a consecutive block of n bits.
(Where n is the smallest integer greater than log<INF>2</INF> x.)
(ii) For direct sequence transmissions using m-ary modulation,
consecutive blocks of log<INF>2</INF> m bits from the shift register
must be used to select the transmitted signal during each interval.
(e) The station records must document all SS emission transmissions
and must be retained for a period of 1 year following the last entry.
The station records must include sufficient information to enable the
FCC, using the information contained therein, to demodulate all
transmissions. The station records must contain at least the following:
(1) A technical description of the transmitted signal;
(2) Pertinent parameters describing the transmitted signal including
the frequency or frequencies of operation and, where applicable, the
chip rate, the code rate, the spreading function, the transmission
protocol(s) including the method of achieving sychronization, and the
modulation type;
(3) A general description of the type of information being conveyed,
(voice, text, memory dump, facsimile, television, etc.);
(4) The method and, if applicable, the frequency or frequencies used
for station identification; and
(5) The date of beginning and the date of ending use of each type of
transmitted signal.
(f) When deemed necessary by an EIC to assure compliance with this
part, a station licensee must:
(1) Cease SS emission transmissions;
(2) Restrict SS emission transmissions to the extent instructed; and
(3) Maintain a record, convertible to the original information
(voice, text, image, etc.) of all spread spectrum communications
transmitted.
(g) The transmitter power must not exceed 100 W.