Publication: Magyar Közlöny
Issue: MK-2009-104 (Year: 2009, Number: 104)
Era: 2004-2010
Section: 
Paragraph Index: 2145

2. The ideal eye diagram is a superposition of samples of the (undistorted) post detection waveform shifted by multiples of the bit period (0.96 microseconds). 12.4.4 Broadcast message characteristics The UAT system shall support two different message types: the UAT ADS-B message and the UAT ground uplink message. 12.4.4.1 UAT ADS-B MESSAGE The Active portion (see 12.1.2.6) of a UAT ADS-B message shall contain the following elements, in the following order: — Bit synchronization — Message data block — FEC parity. Part I Annex 10 — Aeronautical Communications I-12-9 22/11/07 12.4.4.1.1 BIT SYNCHRONIZATION The first element of the Active portion of the UAT ADS-B message shall be a 36-bit synchronization sequence. For the UAT ADS-B messages the sequence shall be: 111010101100110111011010010011100010 with the left-most bit transmitted first. 12.4.4.1.2 THE MESSAGE DATA BLOCK The second element of the Active portion of the UAT ADS-B message shall be the message data block. There shall be two lengths of UAT ADS-B message data blocks supported. The basic UAT ADS-B message shall have a 144-bit message data block and the long UAT ADS-B message shall have a 272-bit message data block. Note.— The format, encoding and transmission order of the message data block element is provided in Section 2.1 of Part I of the Manual on the Universal Access Transceiver (UAT) (Doc 9861). 12.4.4.1.3 FEC PARITY The third and final element of the Active portion of the UAT ADS-B message shall be the FEC parity. 12.4.4.1.3.1 Code type The FEC parity generation shall be based on a systematic Reed-Solomon (RS) 256-ary code with 8-bit code word symbols. FEC parity generation shall be per the following code:

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