Archived — Gazette Notice No. SMBR-003-04
Notice No. SMBR-003-04 - Amendments to the FM Multiplex Sub-Carrier Standards
The Department announces amendments to the FM multiplex sub-carrier technical standards.
The Departmental standards for FM multiplex sub-carriers are in Section C-7.3.3 of Broadcasting Procedures and Rules Part 3 (BPR-3) and in Section A-2.2.4 of Annex A of Broadcasting Equipment Technical standards 6 (BETS-6). The FM multiplex sub-carriers are used to provide radiocommunication services, such as radio paging and alphanumeric data transmission. The sub-carriers are also used to provide data services related to the FM broadcasting program. The current standards limit the modulation of multiplex sub-carriers in the FM baseband to control the spillover of the FM emissions in the adjacent channel and to minimize the impact of the multiplex sub-carriers on the main audio channel.
Radio Broadcast Data System (RBDS) sub-carrier is a standard multiplex sub-carrier. The RBDS offers a wide range of implementation options such as Program Identification (PI), Program Service (PS) name, Alternative Frequency (AF) list, Traffic Program (TP) identification and Traffic Announcement (TA) signal. Today an increasing number of FM stations in Canada use RBDS, and car radios with RBDS functionality are available from different manufacturers at prices that are only slightly higher than those of conventional radios. As a consequence of the widespread deployment of the RBDS sub-carrier, the capacity available to other multiplex operations is becoming limited.
To enable the deployment of additional sub-carriers services, the Department proposes to make the multiplex sub-carrier standard more flexible by relaxing the restriction on the percentage of modulation below 76 kHz. It is proposed to amend BPR-3 and BETS-6 along the following technical principles:
The modulation of the carrier by the arithmetic sum of all sub-carriers between 20 and 99 kHz shall not exceed 30% referenced to 75 kHz modulation deviation and the modulation of the carrier by the arithmetic sum of all sub-carriers above 76 KHz shall not exceed 10%.
The modulation of the carrier by the arithmetic sum of all sub-carriers between 53 and 99 kHz shall not exceed 20% referenced to 75 KHz modulation deviation and the modulation of the carrier by the arithmetic sum of all sub-carriers above 76 KHz shall not exceed 10%.
The Department will amend BPR-3 and BETS-6 documents in the coming months to reflect the above changes to the technical standard governing FM multiplex sub-carriers.
Copies of this notice are available electronically on the Spectrum Management and Telecommunications Web site at:http://www.ic.gc.ca/spectrum.
Official printed copies of gazette notices can be obtained from the Canada Gazette Web site at:
www.gazette.gc.ca/index-eng.html or by calling the sales counter of Canadian Government Publishing
819-941-5995 or 1-800-635-7943.
November 4, 2004
Spectrum Engineering Branch
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