Section 24: Connection Setup
T
ieline
T E C H N O L O G Y
Page 216
24.7.11.
Bonded Any
Bonded Any
is also only used with manual default profiles. It is used in the
same situations as the
Any
setting except it will be a bonded connection. It
will connect using either two POTS lines or in dual channel ISDN mode. (see
the preceding description for the
Any
setting for further details). This
connection can be used for a stereo signal or it is possible to bond two
channels to gain greater bandwidth. For example if you have two POTS
connections with a bit rate of 14,400, you can bond them to get one 28,800
bps connection. This would achieve better quality for mono audio. (Related
Topic: Phonebook Numbers)
24.8.
Coding and Algorithms
It is appropriate at this point to discuss a little about how coding works and which
algorithms are available within your
T
ieline
codec. Our discussion will primarily
focus on audio coding but some of the information is relevant for video coding as
well.
24.8.1.
What is coding and how does it work?
Coding is performed by a codec (Coder/Decoder), which is simply an
integrated circuit device that encodes an analog signal into a digital bit stream
and can decode this bit stream back to an analog signal.
Codecs can use digital signal processor (DSP) software algorithms to
compress and decompress speech and other audio signals. Algorithms are
clever little beasts that can convert analog signals into digital signals at low bit
rates.
In broadcast, they assist us to conserve valuable bandwidth and send high
quality audio, using minimal bandwidth, which in the real-world would be
impossible to do without their clever audio compression techniques.
In summary, coding algorithms facilitate a reduction in the size of data files
and provide more efficient transmission of audio, video and data.
24.8.2.
Sampling Frequencies, Word Size and Quantization
There is a trade-off between the sampling frequency and the ‘word size’
chosen to convert an analog signal into a digital signal, and the resulting
quality of the converted signal. To understand these concepts we also need to
understand the relationship between ‘sampling’ and ‘quantization’.
