1、 ANSI/CTA Standard Intermediate Frequencies for Entertainment Receivers ANSI/CTA-109-D R-2015 (Formerly ANSI/CEA-109-D R-2015) May 2010 NOTICE Consumer Technology Association (CTA) Standards, Bulletins and other technical publications are designed to serve the public interest through eliminating mis
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6、purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this document to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. This docum
7、ent is copyrighted by the Consumer Technology Association and may not be reproduced, in whole or part, without written permission. Federal copyright law prohibits unauthorized reproduction of this document by any means. Organizations may obtain permission to reproduce a limited number of copies by e
8、ntering into a license agreement. Requests to reproduce text, data, charts, figures or other material should be made to the Consumer Technology Association. (Formulated under the cognizance of the CTA R4 Video Systems Committee.) Published by CONSUMER TECHNOLOGY ASSOCIATION 2015 Technology Phone 800
9、-854-7179; Fax 303-397-2740; Internet http:/; Email Federal Communications Commission (FCC) Regulations: U.S. Code of Federal Regulations (C.F.R.), U.S. Government Printing Office, Washington, D.C. 20401; http:/www.access.gpo.gov/nara/cfr/cfr-table-search.html 3 IFs for Analog FM Broadcast Receiver
10、s FM broadcast receivers typically use 10.7 MHz as the IF. NOTEThis is consistent with the FCC channel spacing requirements in 47 C.F.R 73.207(b). 4 IFs for Analog AM Broadcast Receivers AM broadcast receivers typically use 455 kHz or 450 kHz as the IF. 5 Television Receivers For single-conversion a
11、nalog or digital television receivers, the (one) filter performing the IF function is typically centered on 44 MHz. In the case of double-conversion analog or digital television receivers, a translation of the input signal to a higher first IF may occur, and this may be associated with some rejectio
12、n of interference (e.g., image frequencies). Such double-conversion receivers typically have a second IF, typically with much narrower bandwidth, and typically centered on 44 MHz. Further translation of the 44 MHz IF output to lower frequencies may occur at the discretion of the receiver designer (e
13、.g., to facilitate analog-to-digital conversion), but such lower frequencies are not considered IFs as CEA-109-D defines IF. By using 44 MHz as the first IF, analog television receiver designs benefit from associated protections built into the FCC channel assignments. In addition, both analog and di
14、gital television receiver designs benefit from the identification of TV-IF spectrum that could be vulnerable to interference from any new services that might seek to use this band. 1 CEA-109-D 5.1 IFs for Single Conversion Analog NTSC Television Receivers Single conversion analog NTSC television rec
15、eivers shall use 41.25 MHz as the IF for the sound carrier and 45.75 MHz as the IF for the picture carrier. NOTEThis is consistent with the FCC channel spacing requirements in 47 C.F.R. 73.698. In addition, 47 C.F.R. 73.682(a)(3) requires that the aural center frequency shall be 4.5 MHz higher than
16、the visual carrier frequency. 5.2 IFs for Single Conversion Digital Television Receivers Single conversion digital television receivers typically occupy an IF between 41 and 47 MHz. 5.3 IFs for Double Conversion Analog and Digital Television Receivers Both Double conversion analog and digital televi
17、sion receivers should use frequencies above 894 MHz for the first IF. NOTEThere is a band used by unlicensed transmitters at 902-928 MHz. Concerning power usage, see 47 C.F.R. Part 15. Double conversion tuners should use the frequencies enumerated in Section 5.1 or 5.2 for the second IF. 2 Consumer
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