Power Subsystem; Narrowband Communication Protocols; Wideband Communication Protocols; Sampling Rate And Inherent Bandwidth - Polycom SoundStation VTX1000 Brochure

UNDER THE HOOD OF THE SOUNDSTATION VTX 1000
which is helpful in achieving an optimal match to minimize line reflections while meeting
individual country requirements. This interface controller is commanded and the software
is updated via the cable that connects it to the SoundStation VTX 1000 console.
Power Subsystem. The main power supply is a full-range (100 — 264VAC, 50/60 Hz)
switching supply integrated into the Palomod. 22VDC is sent to the console, where it is
converted to five lower voltages by local linear and switching regulators. The 22 VDC is
highly regulated and conditioned to maintain very low noise in the analog sections of the
phone.
Narrowband Communication Protocols. When connected to a far end in narrowband
mode, audio is carried over the twisted-pair phone line via conventional analog
techniques.
Wideband Communication Protocols. Wideband audio is transmitted by first compressing
the near-end audio signal with a high-bandwidth codec selected according to call
requirements from a menu including G.722.1, G.722.2, Siren14, and proprietary codecs,
and communicating it via a proprietary modem which is designed to optimize latency,
connect time, bidirectional data rate, and link reliability.
Sampling rate and inherent bandwidth. The basic audio sampling rate is 48 kHz (which
gives a higher theoretical bandwidth limit than even the 44.1 kHz used by Compact
Disks). The inherent hardware bandwidth (not including speaker and mics) within the
SoundStation VTX 1000 is consequently greater than 22 kHz. Internal mics and speaker
are certified to 14kHz. Interfaced to an external Vortex, the system can operate to 22 kHz.
Microphone Configuration. Three cardioid mics provide consistent frequency and
sensitivity through a 14 kHz frequency range, around the entire 360 degree coverage
pattern. This compares to the cardioid and hypercardioid patterns of Polycom's earlier
systems, all of which were limited to 3.3 kHz.
The internal microphones can be disabled via the user interface, which can be very useful
in some special situations.
Speaker configuration. Acoustic suspension speaker in an isolated enclosure, bandwidth
to 14 kHz (the internal speakers in SoundStation and SoundStation Premier are limited to a
top end of 3.3 kHz.). The internal speaker can be disabled via the user interface, which
can be very useful in some special situations.
External I/O. The SoundStation VTX 1000 has separate line-level input and output (AUX
IN and AUX OUT) for interfacing with external systems. This is different from the
SoundStation and SoundStation Premier, in which only one connection is available and
must be switched between input and output.
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