9.2 A Closer Look at CobraNet
Licensed by Cirrus, CobraNet is a protocol, fi rmware and hardware that lets you trans- mit digital audio over a
This section provides an overview of CobraNet. Cirrus Logic has provided a number of technical papers that describe CobraNet in detail. These papers are available at: http://www.cobranetinfo.com.
9.2.1 Fast Ethernet (100Base-T)
Fast Ethernet
In larger Fast Ethernet networks, additional hubs, concentrators, and other network hardware are used to form a larger network, as shown in Figure 9.2.
Figure 9.3 Star Topology
Today, commonly available networking cards are
The maximum length of cable for CobraNet is the same as for Ethernet:100 meters over
9.2.2 Audio Specs
Sample rate: CobraNet can handle sample rates of 48 kHz or 96 kHz.
Bit depth: Set each channel to transmit
Latency: The transmitter and receiver buffers required for reliable transmission are set to 256 samples as a default. This gives a network transmission latency of 5.333 mS (256 samples at 1/48 kHz per sample).
9.2.3 Bundles and Audio Channels
You assign all audio channels to groups called Bundles for transmission over the
CobraNet network. Bundles were formerly called Network Channels.
A bundle can carry up to 8 audio channels. Up to 8 bundles can be sent in a 100 Mbps line, depending on the signal’s bit depth and sampling rate. Only 4 bundles are avail- able when 96 kHz sampling rate is in use.
Figure 9.4
The usual assignment is 8 channels at 20 bits. You can use fewer channels per bundle, but maximum size bundles are suggested for the most effi cient use of network band- width. If
Operation Manual | page 51 |