Signaling Circuit; Bluetooth/Gps Circuit - Kenwood NX-5800 Service Manual

2.4.8 Signaling Circuit

2.4.8.1 Encode (QT/DQT/DTMF/2-tone/MSK)
Each signaling data signal of QT, DQT, DTMF, 2-tone and MSK is generated by IC706, superposed on a modulation signal and output
to TX VCO and PLL IC.
2.4.8.2 Decode (QT/DQT/DTMF/2-tone/MSK)
The audio signal is removed from the FM detection signal sent to the IC706 and the resulting signal is decoded by IC706.

2.4.9 Bluetooth/GPS Circuit

The main component of the Bluetooth/GPS circuit is Bluetooth / GPS IC (IC5) on BT/GPS unit.
The clocks of Bluetooth/GPS IC require 19.2MHz for core and 32.768kHz slow clock (X1 and X2) for UART.
Bluetooth/GPS IC communicates to the OMAP processor (IC706) on the HCI UART. Interface of UART & Digital audio (PCM) between
the OMAP processor (IC706) and the Bluetooth/GPS IC (IC5), have level conversion at the level shift IC (IC6 and IC7) on BT/GPS unit.
The Bluetooth/GPS IC is powered by 1.8V and 3.3V which are supplied from 2 discrete external regulators (IC2 and IC3) on BT/GPS
unit.
IC706
MPU/DSP
Main unit
2.4.9.1 Bluetooth Circuit
The Bluetooth / GPS IC (IC5) support Bluetooth 3.0 up to HCI level.
TX/RX frequency is 2400-2483.5MHz (79ch Hopping, 2402-2480MHz, 1MHz step). Transmitting power is +2dBm at Bluetooth anten-
na input.
Using the printed antenna with Bluetooth, and connected to the Bluetooth / GPS IC (IC5) through the saw filter (L11).
Frequency configuration for Bluetooth is following:
There are two LO modes: 2X and Offset LO (OSLO). 2X where LO is 2*RF_FREQ (e.g. when transmitting at 2441MHz it is at
4882MHz). OSLO where LO is at (2/3)*RF_FREQ (e.g. when transmitting at 2441MHz it is at 1627.333MHz).
In RX the 2X is always used.
In GFSK TX if power is >10dBm then OSLO is used
In EDR2 TX if power is >-12dBm then OSLO is used
In EDR3 TX if power is >-12dBm then OSLO is used
Otherwise 2X is used for TX as well.
2.4.9.2 GPS Circuit
The GPS RF signal is received with the active antenna, and connected to the Bluetooth / GPS IC (IC5) through the terminal (CN5)
and saw filter (L9).
The output is passed to pin L2 of the GPS IC. The input match for pin L2 comprises of C38, C36 and L7.
The control and data lines for the GPS IC are GPS_PA_EN, BTFM_nSHUTDOWN, GPS_TX and GPS_RX.
GPS_TX and GPS_RX are shared with Bluetooth data line.
Frequency configuration for GPS is following: Lo is GPS: 1571.324MHz
GPS
antenna
Antenna
connector
BT
antenna
1-20 (No.RA017<Rev.002>)
IC6
UART UART
Level
shift IC
IC7
PCM PCM
Level
shift IC
Module (BT/GPS) unit
Fig.5 Bluetooth/GPS circuit
BPF
GPS ANT ALM
GPS
GPS ANT PWR
detect
3.3V
33GPS
BPF
Fig.6 GPS circuit
IC5
UART
BPF
BT/GPS IC
PCM
BPF
X1 X2
TCXO 32.768kHz
19.2MHz Clock
VBAT1(A2)
TCXO_LDO_IN(H1)
GPS_LNA_IN(L2)
VDDS
GPS TX
BT_HCI_UART_TX(A4)
GPS_RX
BT_HCI_UART_RX(B5)
BTFM_nSHUTDOWN(A6)
GPS_PA_EN(G3)
TCXO_CLK_LV(F1)
BT_RF
RTC_CLK(H9)
BT/GPS IC
Bluetooth
antenna
GPS
antenna
connector
CN5
33BT
3.3V
1.8V
18BT
IC706
LEVEL
SHIFT
MPU/DSP
TCXO
19.2MHz
OSCILLATOR
32.768kHz