Clear-Com VOICE2 - Manual (Page 52)

Vitec Group Communications
VoICE IP Interface User Manual
3 - 1 2
CODEC Characteristics
• Sample Rate: This is the rate at which the audio signal is
sampled. 8KHz is the equivalent of telephone quality. The higher
the sample rate is, the clearer is the sound. But a higher rate also
means more bandwidth used in the IP network for equivalent
quality. There are 3 different sample rates, 8, 16 and 32 KHz.
• Codec Bandwidth: This is the bandwidth taken by the encoded
audio data. It does not include all the TCP/IP and VPN overhead.
• Total Bandwidth: That is the total bandwidth taken by the codec
and the serial port (at 19,200 baud with full utilization) on one
channel. The number in parenthesis is the bandwidth used when
4 channels are enabled. Those are average measurements in a
dedicated network.
• Delay: This is the end-to-end delay measured on a dedicated
private IP network while minimizing network jitter buffers to 10-20
ms and disabling echo cancel (setting echo tail to 0).
Speex 20 ms 32 kHz 7.45 kbps 20 (81)
kbps 70
ms 10 Hz - 16
kHz
Speex 20 ms 32 kHz 9.55 kbps 22 (89) 70
ms 10 Hz - 16
kHz
Speex 20 ms 32 kHz 11.6 kbps 24 (98)
kbps 70
ms 10 Hz – 16
kHz
Speex 20 ms 32 kHz 14.6 kbps 27 (110)
kbps 70
ms 10 Hz - 16
kHz
Speex 20 ms 32 kHz 18.6 kbps 31 (126)
kbps 70
ms 10 Hz – 16
kHz
Speex 20 ms 32 kHz 22.4 kbps 35 (141)
kbps 70
ms 10 Hz - 16
kHz
Speex 20 ms 32 kHz 25.6 kbps 38 (154)
kbps 70
ms 10 Hz – 16
kHz
Speex 20 ms 32 kHz 29.6 kbps 42 (170) 70
ms 10 Hz - 16
kHz
Speex 20 ms 32 kHz 36 kbps 49 (195)
kbps 70
ms 10 Hz – 16
kHz
Speex 20 ms 32 kHz 44 kbps 57 (227)
kbps 70
ms 10 Hz – 16
kHz
CODEC CHARACTERISTICS