msm7584c Oki Semiconductor, msm7584c Datasheet - Page 19

• Manufacturer Part Number: msm7584c
• Description: Pi /4 Shift Qpsk Modem/adpcm Codec
• Manufacturer: Oki Semiconductor

¡ Semiconductor
(RSSI-ADC)
RSSI, RSGAIN
RSSI input and level adjustment.
RSSI is connected to the inverting input pin of the internal amplifier. RSGAIN is connected to
the output pin of the amplifier.
Adjust the gain and DC so that the signal amplitude is between 0.7 V and 2.1 V on the RSGAIN
pin. See Fig. 7 for connection.
SGRS
Internal reference voltage output for the RSSI - ADC.
The output voltage is 2.0 V. Insert an approx. 0.1 mF bypass capacitor between this pin and the
AGM pin.
RSSI signal
Gain: A = R2/R1 = 1.4/ (Vmax - Vmin)
DC adjustment value : Vadj = A/(1+A) ¥ ((Vmax + Vmin) /2– 1.4)
Gain = R2/R1
if R1 + R2 20 kW
R1
R2
Set the register CR20 to the DC adjustment value nearest to Vadj.
See the control register map (CR20) for setup values.
Figure 7 RSSI-ADC Interface
RSGAIN
RSSI
CR20:B7 to B3
–
+
ADJUST
DC
ADC
Reference
generator
voltage
CR19:B7 to B0
Control
register
MSM7584C
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