Power Supply; Decode - Kenwood TK-2317 Service Manual

TK-2317
■ High-speed data (2-tone)
High-speed data (HSD) is output from pin 3 of the MCU.
HSD deviation made by an adjustment in the MCU is passed
through the low pass CR fi lter and then applied to the base-
band (IC812).
The signal is mixed with the audio signal and goes to the
VCO and TCXO.
■ MSK/DTMF
The MSK/DTMF signal is generated in the baseband IC
(IC812). The signal passes through the D/A converter (in-
side the baseband IC812) and is routed to the VCO. When
encoding the MSK/DTMF, the microphone input signal is
muted.
6-2. Dceode
■ QT/DQT
The output signal from the IF IC (IC401) enters the MCU
(IC820) through IC812. IC820 determines whether or not
the QT or DQT matches the preset value, and controls the
AFSW and speaker output sounds according to the squelch
results.
■ 2-tone
Part of the received AF signal output from the IF IC (IC401)
passes through the baseband IC (IC812) goes to the other
AF amplifi er IC808, is compared, and then goes to IC820.
IC820 checks whether or not the 2-tone data is necessary. If
it matches, IC820 carries out a specifi ed operation, such as
turning the speaker on.
■ DTMF / MSK
The DTMF and MSK input signal from the IF IC (IC401)
goes to IC812. The decoded information is then processed
by the MCU.

7. Power Supply

There are fi ve 5V power supplies and three 3.3V power
supplies: 50M, 50V, 50C, 50R, 50T, 33M, 33MS and 33B.
50M and 33M are always output while the power is on.
33MS is always output, but turns off when the power is
turned off, to prevent malfunction of the MCU.
50C is a common 5V and is output when SAVE is not set
to ON.
50R is 5V for reception and output during reception.
50T is 5V for transmission and output during transmis-
sion.
50V is 5V for the SP/MIC connector.
33B is 3.3V for the baseband IC (IC812).
28
CIRCUIT DESCRIPTION / 电路说明
■高速数据 (2- 音 )
高速数据 (HSD) 从微处理器的针脚 3(HSDENC) 输出。信号
通过低通 CR 滤波器。由微处理器进行调整的 TX 频偏被施加
到基带 IC(IC812)。
此信号与音频信号混合，然后送入 VCO 和 TCXO。
■ MSK/DTMF
MSK 和 DTMF 信号由基带 IC(IC812) 生成。
MSK 信号从 IC812 的针脚 24 输出。此信号通过数模转换器，
然后发送给 VCO。编码 MSK 和 DTMF 信号时，麦克风输入信号
被静音。
6-2. 解码
■ QT/DQT
I F IC( IC401) 的 输 出 信 号 通 过 IC812 送 入 微 处 理 器
(IC820)。I C820 确 认 Q T 或 DQ T 是 否 与 预 设 值 匹 配， 控 制
AFSW，然后扬声器根据静噪结果输出声音。
■ 2- 音
部分接收的 AF 信号从 IF IC(IC401) 输出，然后通过基带
IC( IC812) 送入另一个 AF 放大器 C808 进行比较，然后送入
IC820。IC820 检查是否需要 2- 音数据。如果匹配，IC820 就
执行特定的操作，如打开扬声器。
■ DTMF/MSK
IF IC(IC401) 的 DTMF 和 MSK 输入信号送入 IC812。然后
由微处理器处理解码信息。
7. 电源
微处理器有 5 个 5V 电源和 2 个 3.3V 电源。
电源打开时，50M 和 33M 总是输出。5M 总是输出，但电源
关闭时 33MS 关闭，以防止微处理器出现故障。
50C 是普通的 5V 电源，它在 SAVE 没有设为 ON 时输出。
50R 是接收用 5V 电源，它在接收期间输出。
50V 是 SP/MIC 用 5V 电源。
33B 是基带 IC (IC812) 用 3.3V 电源。