R&S RTO6 - 13.5 Audio signals (option R&S RTO6-K510); 13.5.1 Audio protocols; 13.5.1.1 I²S standard

Protocol analysis
R&S
®
RTO6
529User Manual 1801.6687.02 ─ 05
Remote commands
Remote commands to retrieve decode results are described in Chapter 24.17.5.3,
"Decode results", on page 1735
.
13.5
Audio signals (option R&S RTO6-K510)
The R&S R
T
O6 can analyze several standard and de-facto industry standard signals:
I²S Inter-IC Sound standard audio format, left justified and right justified data formats
and Time Division Multiplexed (TDM) audio format.
● Audio protocols..................................................................................................... 529
● Audio configuration............................................................................................... 531
● Audio trigger..........................................................................................................537
● Audio decode results.............................................................................................541
● Track..................................................................................................................... 542
● Trend.....................................................................................................................545
13.5.1 Audio protocols
All audio protocols use 3 lines:
●
The clock line generates the bit clock.
●
The word select line (WS, also known as word clock) defines the frame start and
the maximum length of the data word.
For pulse code modulated signals (I²S standard, left and right justified data for-
mats), the level of the WS signal assigns the data words to the left and right chan-
nels.
TDM uses frame synchronization pulses on the WS line to identify the beginning of
a frame.
●
The data line transmits the audio data in time-multiplexed data channels.
13.5.1.1 I²S standard
I²S standard interfaces transmit two PCM coded audio channels. The WS line selects
the channel being transmitted - left or right channel. Usually, 32 bits are transmitted on
each channel. The data word can be shorter than the channel length, and the receiver
ignores the remaining bits. The first byte of the audio word is delayed one clock period
from the leading edge of the word select pulse. The R&S RTO6 can decode I²S stan-
dard signals with MSBF and LSBF bit order.
Audio signals (option R&S RT
O6-K510)