Zhone 2004 ユーザーガイド

Inter-arrival jitter is the difference in relative transit time for two packets. It is 
the difference between the packet's RTP time-stamp and the receiver's clock at 
the time of arrival of the packet. 

As shown in the equation below, this is equivalent to the difference in the 
relative transit time for two packets: the relative transit time is the difference 
between a packet's RTP time-stamp and the receivers clock at the time of 
arrival, measured in the same units.

If Si is the RTP time-stamp from packet i and Ri is the time of arrival in RTP 
time-stamp units for packet i, then for two packets i and j, D may be 
expressed as:

D(ij) = (Rj

−Ri) − (Sj−Si) = (Rj−Sj) − (Ri−Si)

The interval jitter is calculated continuously as each data packet i is received 
from source SSRC

−n, using this difference D for that packet and of the 

previous packet i

−1 in order of arrival (not necessarily in sequence), 

according to the formula:

J = J + ({D (i

−l, i)}−J)/16

The Jitter Delay should be set only by a Network Administrator. To set jitter 
delay (0 to 50 ms 

− default is 0 ms), follow the steps below.

Type “J” on the Voice Configuration menu (Figure 4.27) to select Set Jitter 
Delay. The IAD prompts you to enter the number of milliseconds to delay.

Type the delay value and press Enter. The IAD saves the jitter delay and 
displays the Voice Configuration menu so you can continue with other 
voice path configuration.

To display the current jitter delay value, type “D” on the Voice Configuration 
menu (Figure 4.27). The IAD displays the current value.:

Press any key to display the Voice Configuration menu and continue.

To display the Voice Port Configuration Menu (Figure 4.48), type “P” on the 
Voice Configuration menu (Figure 4.27). Voice port settings should be 
changed only under certain circumstances. Please consult your service 
representative prior to changing these setups.