Metering Injection; Fig. 12: Metering Pulse Timing Diagrams - Alcatel MTK-40131 Datasheet And User Manual

Metering Injection

Metering pulses of selectable frequency
(12 or 16 kHz) and programmable
amplitude can be injected into either
analog channel independently. The
width of the injected pulse is determi-
ned by the user ("on/off mode"), or by
an internal timer ("burst mode") which
can be set by the user from 2ms to 510
ms in steps of 2ms. The metering signal
is always a multiple of half metering
periods. See fig. 12.
/MPI
metering
/MPI
metering

Fig. 12: Metering pulse timing diagrams.

The metering level on the line is set by: Vlm = (Vgen . Zm)/(Zm + Zcom)
where:
Vlm = metering pulse level on the line
Vgen = set level of the metering generator
Zm = impedance of the metering load
Zcom = CO impedance at the metering frequency.
Metering is initiated on a channel by
an active low state on the correspond-
ing /MPI bit in the GCI C/I byte.
on/off mode
burst mode
t
mburst
21
MTK-40131
The metering level Vgen is selectable
from 0 to a maximum level of
230mVrms (500m line with
Zco=900Ω) in 15 linear steps. The
internal tolerance on the metering sig-
nal level is ±10%.