Key Input; Signaling Circuit; Encode - Kenwood TK-2317 Service Manual

CIRCUIT DESCRIPTION / 电路说明

5-4. Key Input

Keys and channel selector circuit.
The signal from the keys and channel selector are direct-
ly input to the MCU, as shown in Figure 10.

6. Signaling Circuit

6-1. Encode

■ Low-speed data (QT, DQT)
Low-speed data is output from pin 2 of the MCU. The sig-
nal passes through the low pass CR fi lter, and goes to the
baseband IC (IC812). The signal is mixed with the audio sig-
nal and goes to the VCO and TCXO (X1) modulation input
after passing through the D/A converter inside the baseband
IC (IC812) for BAL adjustment.
IC820
MCU
S
A
B
C
Fig. 10 Key input / 图 10 键输入
IC820
MCU
2 18
LSDO
ALT
3 21
HSDENC
MIC
Fig. 11 Encode / 图 11 编码
5-4. 键输入
键和信道选择电路。
如图 10 所示， 键和信道选择器的信号被直接输入微处理器。
Selector
Side2
Side1 PTT
6. 信令电路
6-1. 编码
■低速数据 (QT,DQT)
低速数据从微处理器的针脚 2(LSDO) 输出。信号通过低通
CR 滤波器器，并且送到基带 IC( IC812)。此信号与音频信号
混合，在基带 I C( IC812) 中进行信号处理之后，进入 V C O 和
TCXO(X1) 调制输入。
IC812
Baseband IC
24
VCO
MOD2
23
TCXO
MOD1
TK-2317
27