IEC 61883-6:2005

INTERNATIONAL IEC
STANDARD 61883-6
Second edition
2005-10
Consumer audio/video equipment –
Digital interface –
Part 6:
Audio and music data transmission protocol

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INTERNATIONAL IEC
STANDARD 61883-6
Second edition
2005-10
Consumer audio/video equipment –
Digital interface –
Part 6:
Audio and music data transmission protocol

 IEC 2005  Copyright - all rights reserved
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– 2 – 61883-6  IEC:2005(E)
CONTENTS
FOREWORD.6

1 Scope.8
2 Normative references .8
3 Terms and definitions .8
4 Reference model for data transmission.10
4.1 Application layer.11
4.2 Adaptation layer .11
4.3 Packetization layer .12
5 Transport requirements .13
5.1 Arbitrated short bus reset .13
5.2 Bit, byte, and quadlet ordering.13
6 Packet header for audio and music data .13
6.1 Isochronous packet header format.13
6.2 CIP header format .13
7 Packetization.14
7.1 Packet transmission method.14
7.2 Transmission of timing information .14
7.3 Time stamp processing.15
7.4 Transmission control .16
8 Event types .17
8.1 General .17
8.2 AM824 data.20
8.3 32-bit floating-point data.28
8.4 24-bit * 4 audio pack .28
8.5 32-bit generic data .29
9 FDF definition.29
9.1 Introduction .29
9.2 Basic format .30
9.3 Special format .31
10 FDF definition for AM824 data .32
10.1 Definition of N-flag .32
10.2 Supplementary SFC definition .32
10.3 Clock-based rate control mode (FDF = 0000 0xxx ) .33
10.4 Command-based rate control mode (FDF = 00001xxx ) .34
11 AM824 adaptation process .35
11.1 Introduction .35
11.2 Basic sequence conversion .35
11.3 Sequence multiplexing .35
11.4 Compound data block structure .36
12 AM824 sequence adaptation layers .40
12.1 General .40
12.2 DVD-Audio .56
12.3 SACD definition.59

61883-6  IEC:2005(E) – 3 –
Annex A (informative) Blocking transmission method .64
Annex B (informative) Synchronization issues.66
Annex C (informative) Catching up in non-blocking transmission method .68
Annex D (informative) Transport characteristics.69

Bibliography.77

Figure 1 – Reference model for audio and music data transmission .10
Figure 2 – Reference model for AM824 data transmission .11
Figure 3 – Implementation example of receiver .12
Figure 4 – Isochronous packet header .13
Figure 5 – Common isochronous packet (CIP) format .14
Figure 6 – Non-blocking transmission method.16
Figure 7 – Transmission parameters .17
Figure 8 – Cluster events.18
Figure 9 – Pack and cluster events .19
Figure 10 – Pack event with 24-bit event sequence.19
Figure 11 – Generic AM824 format .20
Figure 12 – AM824 data with SUB LABEL.20
Figure 13 – AM824 LABEL allocation map (informative).21
Figure 14 – IEC 60958-conformant data format.22
Figure 15 – MBLA data .22
Figure 16 – Raw audio data .23
Figure 17 – Alignment of 20-bit data in 24-bit field .23
Figure 18 – MIDI conformant data format .24
Figure 19 – No-data format .24
Figure 20 – High-precision multi-bit linear audio data.25
Figure 21 – Generic high-precision quadlet sequence .25
Figure 22 – Generic ancillary data .26
Figure 23 – Ancillary no data .26
Figure 24 – General format for ASID.27
Figure 25 – General format for application-specific ancillary data .28
Figure 26 – 32-bit floating-point data format.28
Figure 27 – 24-bit * 4 audio pack format .29
Figure 28 – 32-bit generic data format .29
Figure 29 – Generic FDF definition .30
Figure 30 – FDF code for NO-DATA packet .31
Figure 31 – Structure of FDF for AM824 data type .32
Figure 32 – SFC interpretation.32
Figure 33 – FDF for AM824 and AM824 LABEL space (informative).33
Figure 34 – Adaptation to AM824 sequence.35
Figure 35 – Asynchronous sequence multiplexing.36
Figure 36 – Example of compound data block .37

– 4 – 61883-6  IEC:2005(E)
Figure 37 – Condition of AM824 rule.37
Figure 38 – Generic compound data block structure .38
Figure 39 – Example of unspecified region structure.39
Figure 40 – Generic one-bit audio quadlet .47
Figure 41 – Generic one-bit audio quadlet sequence .48
Figure 42 – One-bit audio DST encoded quadlet.48
Figure 43 – Multiplexing of MIDI data streams .49
Figure 44 – High-precision first ancillary data .50
Figure 45 – IEC 60958-conformant data with high-precision data.51
Figure 46 – Common and application-specific ancillary data with high-precision data.52
Figure 47 – High-precision channel assignment ancillary data .52
Figure 48 – Example of high-precision data .53
Figure 49 – Example of double-precision data .54
Figure 50 – Example of double-precision compound data .55
Figure 51 – Data transmitted at data starting-point.56
Figure 52 – Data transmitted at every data block .57
Figure 53 – Ancillary data for CCI .57
Figure 54 – Ancillary data for ISRC.58
Figure 55 – Basic data block of DVD-Audio stream .58
Figure 56 – Example of DVD-Audio data.59
Figure 57 – SACD ancillary data .60
Figure 58 – SACD supplementary data .61
Figure 59 – SACD Track_Mode&Flags data .61
Figure 60 – SACD Track_Copy_Management data .61
Figure 61 – Example of SACD stream in the case of six channels.62
Figure 62 – Example of SACD stream in the case of five channels.63
Figure A. 1 – Blocking transmission method.64
Figure D.1 – Two-node bus.72
Figure D.2 – Three-node bus .73
Figure D.3 – Thirty-five-node bus.74
Figure D.4 – Sample-clock recovery jitter attenuation template .75
Figure D.5 – Sample clock jitter measurement filter characteristic.76

Table 1 – Isochronous packet header fields .13
Table 2 – CIP fields .14
Table 3 – LABEL definition.21
Table 4 – SB and SF definitions.22
Table 5 – ASI1 definition.23
Table 6 – VBL (valid bit length code) definition .23
Table 7 – LABEL definition for one-bit audio (plain) .23
Table 8 – LABEL definition for one-bit audio (encoded).24
Table 9 – C (counter) definition.24
Table 10 – Num. (slot number) definition .25

61883-6  IEC:2005(E) – 5 –
Table 11 – LABEL definition for ancillary data type .26
Table 12 – LABEL definition for common ancillary data.26
Table 13 – CONTEXT definition .27
Table 14 – SUB LABEL definition for ASID .27
Table 15 – LABEL definition for application specific ancillary data .28
Table 16 – Subformat and FDF allocations .29
Table 17 – DBS for AM824 and 32-bit floating-point data .30
Table 18 – DBS for 24-bit * 4 audio pack .30
Table 19 – Event type (EVT) code definition .30
Table 20 – Default SFC table.30
Table 21 – TRANSFER_DELAY for blocking transmission .31
Table 22 – Default SFC table for FDF = 0000 0xxx .33
Table 23 – TRANSFER_DELAY for blocking transmission .34
Table 24 – Default SFC table for FDF = 0000 1xxx .34
Table 25 – Sampling frequency in IEC 60958-3:1999.40
Table 26 – Sampling frequency in IEC 60958-3:2002.41
Table 27 – Original sampling frequency .41
Table 28 – Up or down sampling ratio of 32 kHz line.42
Table 29 – Up or down sampling ratio of 44.1 kHz line.42
Table 30 – Up or down sampling ratio of 48 kHz line.42
Table 31 – Clock accuracy in IEC 60958-3.42
Table 32 – Cases.43
Table 33 – Examples .44
Table 34 – Relation of values in IEC 60958-3 and A/M protocol .46
Table 35 – Sampling frequency definition of one-bit audio .47
Table 36 – TRANSFER_DELAY for blocking transmission in the case of the one-bit audio.47
Table 37 – SFC definition of one-bit audio for high-speed AM824 data transfer .49
Table 38 – Channel definition .50
Table 39 – Accuracy definition .50
Table 40 – Recommended rules.51
Table 41 – Channel assignment definition.52
Table 42– ASI2 definition for DVD-Audio .56
Table 43– DVD-Audio specific ancillary data.56
Table 44 – Data transmitted at starting-point .57
Table 45 – Data transmitted at every data block .57
Table 46– data information (informative).60
Table 47 – Validity flag definition .60
Table A. 1 – TRANSFER_DELAY for differing values of STF .65

– 6 – 61883-6  IEC:2005(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CONSUMER AUDIO/VIDEO EQUIPMENT –
DIGITAL INTERFACE –
Part 6: Audio and music data transmission protocol

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61883-6 has been prepared by Technical Area 4: Digital system
interfaces, of IEC technical committee 100: Audio, video and multimedia systems and
equipment.
This second edition of IEC 61883-6 cancels and replaces the first edition published in 2002.
This edition contains the following significant technical changes with respect to the previous
edition.
a) It extends the AM824 data format transmission and specifies more details in order to
reduce the ambiguities of the first edition.
b) It introduces new Clauses 4, 10, 11 and 12 as well as Annex D and, in 8.2, specifies new
data types for SMPTE time code, sample count, high-precision multi-bit linear audio and
ancillary data.
c) It changes the terminology “raw audio data” to “multi-bit linear audio (MBLA)”.
d) It defines, in Clause 11, sequence multiplexing and MIDI data required to the AM824
adaptation process.
61883-6  IEC:2005(E) – 7 –
e) It describes, in Clause 12, application-specific data transmission such as DVD-audio and
SACD.
f) It specifies, in Clause 20, the N-flag that indicates command-based rate control and
defines new sampling frequency code (SFC) definition and interpretation.
The text of this standard is based on the following documents:
FDIS Report on voting
100/1001/FDIS 100/1024/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 61883 consists of the following parts under the general title Consumer audio/video
equipment – Digital interface:
Part 1: General
Part 2: SD-DVCR data transmission
Part 3: HD-DVCR data transmission
Part 4: MPEG2-TS data transmission
Part 5: SDL-DVCR data transmission
Part 6: Audio and music data transmission protocol
Part 7: Transmission of ITU-R BO.1294 System B
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 8 – 61883-6  IEC:2005(E)
CONSUMER AUDIO/VIDEO EQUIPMENT –
DIGITAL INTERFACE –
Part 6: Audio and music data transmission protocol

1 Scope
This part of IEC 61883 describes a protocol for the transmission of audio and music data
employing IEEE 1394 and specifies essential requirements for the application of the protocol.
This protocol can be applied to all modules or devices that have any kind of audio and/or
music data processing, generation and conversion function blocks. This document deals only
with the transmission of audio and music data; the control, status and machine-readable
description of these modules or devices should be defined outside of this document according
to each application area.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60958 (all parts), Digital audio interface
IEC 61883-1:2003, Consumer audio/video equipment – Digital interface – Part 1: General
IEC 61883-6:2002, Consumer audio/video equipment – Digital interface – Part 6: Audio and
music data transmission protocol
IEEE 754:1985, Standard for Binary Floating-Point Arithmetic
IEEE 1394: Standard for a High Performance Serial Bus
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61883-1, as well as
the following, apply.
3.1
32-bit floating-point data
data type which is defined in IEEE 754:985
3.2
AM824 Data
32-bit data consisting of an 8-bit label and 24-bit data
3.3
A/M protocol
protocol for the transmission of audio and music data over IEEE 1394

61883-6  IEC:2005(E) – 9 –
3.4
ASID
Audio Software Information Delivery (see http://riaj.japan-music.or.jp/tech/asid/e.html )
3.5
AV/C
Audio Video Control
3.6
DVD
3.7 Digital Versatile Discs (see http://www.dvdforum.org/index.htm)
MIDI
Musical Instrument Digital Interface
NOTE The complete MIDI 1.0 detailed specification, Version 96.1, March 1996, is a specification for the
interconnection of digital music processing devices (for example, keyboards and signal processors) and computers.
3.8
music data
data generally used for controlling a tone generator.
NOTE The data defined in the MIDI specification, which may be called MIDI data, are an example of music data.
3.9
reserved
keyword used to describe objects – bit, byte, quadlet, octet, and field – or the code values
assigned to these objects, the object or the code value being set aside for future
standardization by the IEC
3.10 SACD
SACD Super Audio CD (see http://www.licensing.philips.com/).

3.11
stream
uni-directional data transmission
3.12
time stamp
quantized timing in which an event occurs based on a reference clock
NOTE The reference clock is CYCLE_TIME unless otherwise specified in this standard.

– 10 – 61883-6  IEC:2005(E)
4 Reference model for data transmission
This clause describes a reference model for data transmission.

Transmitter Receiver
Application specification
Application sequence Application sequence
Nominal_
Nominal _
Sampling_Frequency Sampling_Frequency
Tx Rx
Sampling_
Sampling_
Application layer
Frequency
Frequency
A/M protocol
specification
Audio sample Additional info Audio sample Additional info
Adaptation layer
Conversion process
Conversion process
[DBC]
[DBC]
Transfer_ Frequency
Rx
Transfer_ Frequency
Tx
[FDF]
[FDF]
Packetization
layer
packetize Event sequence depacketize Event sequence
CIP layer
IEC  1734/05
Figure 1 – Reference model for audio and music data transmission

61883-6  IEC:2005(E) – 11 –
Transmitter Receiver
Application specification
Application sequence Application sequence
Nominal_ Nominal _
Sampling_Frequency Sampling_Frequency
Tx Rx
Sampling_
Sampling_
Application layer
Frequency
Frequency
A/M protocol
specification
for AM824
Audio sample Additional info Audio sample Additional info
Adaptation layer
[LABEL] [LABEL]
Compound data structure Compound data structure
[DBC]
[DBC]
Transfer_ Frequency
Rx
Transfer_ Frequency
Tx
[FDF]
[FDF]
Packetization
layer
packetize dAM824 sequence epacketize AM824 sequence
CIP layer
IEC  1735/05
Figure 2 – Reference model for AM824 data transmission
Figure 1 gives an outline for audio data transmission from a transmitter to a receiver. It has
four major layers denoted as CIP (common isochronous packet) layer, packetization layer,
adaptation layer and application layer.
4.1 Application layer
Each application defines its own application sequence and the interface to the adaptation
layer. The application sequence in Figure 1 is data in a format such as an audio signal format.
The Nominal_Sampling_Frequency is the ideal sampling frequency for the application
sequence. The range of Sampling_Frequency should be defined by the application. The audio
signal at Nominal_Sampling_Frequency can be reproduced at the actual rate of Sampling_
Frequency in operation. This means that the value of Sampling_Frequency may have some
deviation and/or may vary in time in contrast with Nominal_Sampling_Frequency.
Additional information in Figure 1 is any information other than events of a sequence (audio
samples) being transmitted at a given rate.
4.2 Adaptation layer
The adaptation layer defines a process to convert an application sequence to an event
sequence and vice versa. The conversion process may not be required if an application
sequence and an event sequence have the same structure. If an event sequence consists of
events of 24-bit payload, such as AM824 data defined in 8.2, and if the bit length of an audio
sample of the application sequence is not 24-bit, some conversion between
Sampling_Frequency and Transfer_Frequency may be required (see Figure 2 and Clause 11).
The Transfer_Frequency represents the frequency of occurrence of a data block, which is
equivalent to a cluster event. The Transfer_Frequency is used for describing a conceptual
transmission model.
– 12 – 61883-6  IEC:2005(E)
The transfer rate of an event sequence is 24 * Transfer_ Frequency [bit/sec] in the case of
AM824.
Generally, the adaptation layer is designed in such a way that both the application sequence
at Sampling_Frequency and its Nominal_Sampling_Frequency are carried. In this
specification, Nominal_Sampling_Frequency, which would usually be one of the ancillary data
items, is carried by the SFC (sampling frequency code) which is defined in Clause 10. The
information in Nominal_Sampling_Frequency is necessary for using command-based rate
control or making a copy. On the other hand, Sampling_Frequency is necessary for clock-
based rate control. Although Sampling_Frequency is not explicitly transmitted, it can be
estimated from SYT_INTERVAL and time stamps by the algorithm specified for the AM824
data type.
An application specification defines the process (shown in the grey shaded area of Figure 1)
to convert the signal of the application (application sequence) to an event sequence. This
standard assumes that the application specification is an external document using the
definition of an event sequence for the adaptation process. For several generic data types,
this standard also defines the adaptation layer.
The adaptation to an event sequence is the point at which the packetization process
interfaces to the application. The packetization process can be described as IEEE 1394
adaptation from the point of view that the data stream utilizes IEEE 1394 as its transport.
More details of this layer are described in Clause 12.
4.3 Packetization layer
The AM824 sequence is directly packetized to CIP or depacketized from CIP in the
packetization layer.
The Transfer_Frequency can be implicitly expressed by the output of a locked PLL circuit, as
shown in Figure 3, instead of being explicitly denoted in the packetization layer.

Nominal_Sampling_Frequency Sampling_Frequency
RX RX
Event
Algorithm
sequence
adaptation
SFC AM824 LABEL
Packetization
1 / SYT_INTERVAL
Transfer_Frequency
layer
Rx
Phase
VCO
comparator
SYT match
IEC  1736/05
Figure 3 – Implementation example of receiver

61883-6  IEC:2005(E) – 13 –
5 Transport requirements
5.1 Arbitrated short bus reset
All modules or devices which implement this A/M protocol should have the capability of
"arbitrated short-bus reset" in order to prevent the interruption of audio and music data
transmission when a bus reset occurs.
5.2 Bit, byte, and quadlet ordering
This document adopts the ordering of bit, byte, and quadlet for bus packets in accordance
with IEEE 1394.
6 Packet header for audio and music data
This clause defines the packet format in the CIP layer described in Figure 1.
6.1 Isochronous packet header format
The header for an isochronous packet which conforms to the A/M protocol shall have the
same format given in Figure 4, which is part of the isochronous packet format defined in
IEEE 1394.
data_length tag channel tcode sy
header_CRC
IEC  1737/05
Figure 4 – Isochronous packet header
The isochronous packet header fields are defined with unique values that are specified in
Table 1.
Table 1 – Isochronous packet header fields
Field Value Comments
Tag 01 b This value indicates that a CIP header is included in the packet
Tcode A This value indicates that this is an isochronous data packet
Sy xx This field is reserved. The transmitter shall set this field to 0
unless specified by another application

6.2 CIP header format
IEC 61883-1 defines a two-quadlet CIP header for a fixed length source packet with SYT field.
The CIP header format for an isochronous packet, which conforms to the audio and music
data transmission protocol, shall use the CIP header illustrated in Figure 5.

– 14 – 61883-6  IEC:2005(E)
SPH
0 0 SID DBS FN QPC DBC
rsv
1 0 FMT FDF SYT
IEC  1738/05
Figure 5 – Common isochronous packet (CIP) format
Table 2 defines the fields with unique values that are specified by this protocol.
Table 2 – CIP fields
Field Value Comments
FMT 10 This value indicates that the format is for audio and music
FN 0
QPC 0
SPH 0
SYT xx This field shall contain the time when the specified event shall be
presented at a receiver
FDF xx This field is defined in Clause 10

7 Packetization
7.1 Packet transmission method
When a non-empty CIP is ready to be transmitted, the transmitter shall transmit it within the
most recent isochronous cycle initiated by a cycle start packet. The behaviour of packet
transmission depends on the definition of the condition in which “a non-empty CIP is ready to
be transmitted.” There are two situations in which this condition is defined.
a) In order to minimize TRANSFER_DELAY, the condition of a non-empty CIP being ready
for transmission is defined to be true if one or more data blocks have arrived within an
isochronous cycle. This transmission method is called non-blocking transmission and is
described in detail in 7.4
b) The condition of “non-empty CIP ready” can also be defined as true when a fixed number
of data blocks have arrived. This transmission method is called blocking transmission and
is described in Annex A.
7.2 Transmission of timing information
A CIP without a source packet header (SPH) has only one time stamp in the SYT field. If a
CIP contains multiple data blocks, it is necessary to specify which data block of the CIP
corresponds to the time stamp.
The transmitter prepares the time stamp for the data block which meets this condition:
mod(data block count, SYT_INTERVAL) = 0 (1)

61883-6  IEC:2005(E) – 15 –
where
data block count is the running count of transmitted data blocks;
SYT_INTERVAL denotes the number of data blocks between two successive valid SYTs,
which includes one of the data blocks with a valid SYT. For example, if
there are three data blocks between two valid SYTs, then the
SYT_INTERVAL would be 4.
The receiver can derive the index value from the DBC field of a CIP with a valid SYT using the
following formula:
index = mod((SYT_INTERVAL – mod(DBC, SYT_INTERVAL)),
SYT_INTERVAL) (2)
where
index is the sequence number;
SYT_INTERVAL denotes the number of data blocks between two successive valid SYTs,
which includes one of the data blocks with a valid SYT;
DBC is the data block count field of a CIP.
The receiver is responsible for estimating the timing of data blocks between valid time stamps.
The method of timing estimation is implementation-dependent.
7.3 Time stamp processing
A data block contains all data arriving at the transmitter within an audio sample period. The
data block contains all the data which make up an “event”.
The transmitter shall specify the presentation time of the event at the receiver. A receiver for
professional use shall have the capability of presenting events at the time specified by the
transmitter. A consumer-use or cost-sensitive receiver is not required to support this
presentation-time adjustment capability.
If a function block receives a CIP, processes it and subsequently re-transmits it, the SYT of
the outgoing CIP shall be the sum of the incoming SYT and the processing delay.
The transmitter shall add TRANSFER_DELAY to the quantized timing of an event to construct
the SYT. The TRANSER_DELAY value is initialized with the DEFAULT_TRANSFER_DELAY
value. For professional use, TRANSFER_DELAY may be changed to achieve a shorter
TRANSFER_DELAY value, according to the bus configuration. Products for consumer use are
not required to support the modification of TRANSFER_DELAY.
The DEFAULT_TRANSFER_DELAY value is 354,17 + 125 µs, which accommodates the
maximum latency time of CIP transmission through an arbitrated short bus reset.

– 16 – 61883-6  IEC:2005(E)
7.4 Transmission control
Figure 6 illustrates the non-blocking transmission method.

SYT_INTERVAL = 4
Transmitter
isochronous
cycle
event
Fs = 26,7 kHz
CYCLE_ TIME
arrival time T1 T2 T3 T4
Packet
DBC 3 6 10 13 16
SYT R1 R2 R3 No Info R4
Receiver
event
index 1220
CYCLE_ TIME
R1 R2 R3 R4
TRANSFER_ DELAY
IEC  1739/05
Figure 6 – Non-blocking transmission method
The transmitter shall construct a packet in every nominal isochronous cycle. Each packet
shall comply with the following constraint:
0 <= N <= SYT_INTERVAL (3)
where N is the number of events in the packet.
In normal operation the transmitter shall not transmit events late and shall not transmit
packets early. The resulting conditions may be expressed as follows:
Packet_arrival_time_L <= Event_arrival_time[0] + TRANSFER_DELAY (4)
Event_arrival_time[N-1] <= Packet_arrival_time_F (5)
where
Packet_arrival_time_F is the time (measured in µs) when the first bit of the packet arrives at
the receiver;
Packet_arrival_time_L is the time (measured in µs) when the last bit of the packet arrives at
the receiver;
Event_arrival_time[M] is the time (measured in µs) of the arrival at the transmitter of event
M of the packet. The first event of the packet has M = 0.
Figure 7 illustrates the transmission control rules as described in Clause 7.

61883-6  IEC:2005(E) – 17 –
SYT_INTERVAL = 4
Transmitter
isochronous
cycle
event
CYCLE_TIME
Presentation_time_F
Packet
Presentation_time (SYT value)
Packet_arrival_time_F Presentation_time_
...