User Guide

Technical Documentation
NHD–4
System Module
P.A.M.S
Page 4–19
Original 11/97
The auxiliary AGC can be manually adjusted using the AGC_REF PDM
controls found in the Service Software. Below is a table detailing typical
voltages of the AGC_REF PDM and VC, referenced against CDMA TX
output power.
CDMA TX
Output Power
(dBm)
AGC_REF PDM
(decimal value)
AGC_REF PDM
voltage at C716
(V)
VC
at C109
(V)
23 0 0.798 3.28
21 34 0.583 2.81
19 60 0.456 2.53
17 79 0.367 2.33
15 85 0.333 2.26
The AT–109 is put in its minimum attenuation state for AMPS operation.
During AMPS TX operation the AT–109 control voltage VC will be at its
maximum, 4.35 V, measured at C214. The AGC_REF PDM will be 1.50 V
measured at R222.
AMPS TX Gain Control
NOTE! Be cautious not to confuse the TXI_REF PDM voltage with the
TX_IREF control current. The names are quite similar, but indeed they
are two different signals.
The TXI_REF PDM has 6 tuned values corresponding to the 6 AMPS
power levels used in mobile operation (2–7). The following is a table of
typical values of TXI_REF PDM and TXI voltages, and TX_ICT currents
for the 6 AMPS power levels. There will be variations from phone to
phone.
AMPS
Power
Level
TXI_REF
PDM Voltage
(at R210)
(V)
TXI_REF
PDM
decimal val-
ue
TXI Detector
Voltage
(at N202,
Pin1)
(V)
TX_ICT
(voltage drop
across
R116)
(mV)
2 1.05 14 1.05 44.2
3 1.56 239 1.56 38.6
4 1.92 187 1.92 30.5
5 2.10 168 2.10 22.3
6 2.20 157 2.20 21.9
7 2.26 152 2.26 17.9
While the phone is in AMPS TX mode the TX_IREF current will remain
constant at approximately 1.0 mA. This current can be read indirectly by
measuring the voltage drop across R115. This drop will be approximately
100 mV.