Telos Zephyr Xstream - Manual (Page 142)

USER’S MANUAL
Section 6: AUDIO CODING REFERENCE 130
Mono vs. MONO128 vs. Stereo vs. J-Stereo in Layer-2
With one transmission path,
• L2 Mono 64 provides mono capability.
• The L2 HALF 64 Xmt mode allows operation at 24kHz when this sample rate
is desired, primarily when communicating with “single line” capable Layer‐2
codecs.
With two transmission paths,
• L2 MONO128 provides the best Layer II quality by combining both
transmission paths to achieve a higher bitrate. This mode requires 2 data
paths.
• L2 STEREO mode is simply two simultaneous mono channels.
• L2 J‐STEREO mode uses the “intensity coding” method in order to provide
maximum quality for stereo program material and compensates for any
delay between the two transmission paths.
Sampling Rate
This option sets the sample rate for the transmitted and received coded audio. Input/output is
(usually) independent of the transmission bit rate and is set in the AES/EBU options in the
AUDIO menus.
The Zephyr Xstream may be operated at either 48 kHz or 32 kHz sample rate. 48 kHz offers
lower delay and in certain modes 20 kHz audio bandwidth. However, the 32 kHz rate is
generally preferred for broadcast applications because no bits are wasted on frequencies above
15 kHz – which are not transmitted in analog broadcast services, anyway.
Decoder Limitations
• If your application requires the ability for the two channels to come and go
independently, such as when they are from independent sites, you must use
L3 Dual/Mono or G.722. These are the only modes that support fully
independent operation.
Z ZEPHYR CLASSIC VS XSTREAM COMPARISON!
Zephyr's L3 Stereo receive mode, used to receive two, independent, mono signals, requires that
both channels be connected and operating in order for the decoder to function. Until both
channels are present, the decoder will not output anything, even if the Xmt mode at the other
end is not stereo. Any data dropouts could cause interruption of both audio channels.
Zephyr Xstream's L3 Dual/mono decoder allows for completely independent reception.
Therefore, it can accommodate incoming L3 mono from two sites simultaneously without
compromise.
Of course both Zephyr Classic and Zephyr Xstream can transmit L3 mono audio to two sites.
• A typical application which works perfectly with these modes is the one
used for dual‐language sports broadcasts, with separate studio sites. This is