APPENDIX D
tion since decreasing the ERL by only one or two dB might render the
echo canceller inoperative.
CELP Level
Adjustments
The switches in DIP switch S1 may be used in any combination.
Refer to Section 2 of this manual.
ON OUTPUT LEVEL +7 dBm. PUTS
+7 dB OF GAIN IN OUTPUT (RECEIVE) PATH.
S1-6 AND 7 USED TOGETHER TO
DEFINE E-LEAD CONDITIONING WHEN
CELP LOSES SYNC.
ON CAUSES A GAIN OF +0.5 dB IN
TRANSMIT INPUT PATH
ON CAUSES A GAIN OF –4.0 dB IN
TRANSMIT INPUT PATH (I.E., LOSS OF 4 dB).
ON CAUSES A GAIN OF +1.0 dB IN
TRANSMIT INPUT PATH.
ON CAUSES A GAIN OF –2.0 dB IN
TRANSMIT INPUT PATH (I.E., LOSS OF 2 dB).
ON: INPUT LEVEL IS –16 dBm. PUTS +16 dB
OF GAIN IN THE INPUT (TRANSMIT) PATH.
1 2 3 4 5 6 7 8
036R480DH
With all of the S1 switches in the OFF position, the CELP is set up for 0
dBm (0 TLP) input and output signal levels. The CODEC used in the
CELP is designed to use 0 dBm input and output levels. The switches are
used to achieve a 0 dBm input to the CODEC based on the input signal be-
ing placed on the interface.
CELP Echo
Canceller
The Echo Canceller is always enabled on the CELP card. It is not possible
to disable it.
D-16
