SSM-75E 话筒按键 10 CHAPTER SSM-75E Microphone Switches
本章要点：SSM-75E 话筒上除了 PTT 之外，还有 UP/DOWN、MUTE 以及 P1~P4 四个可编程键，它们分别复刻了前面板的电 源/锁定、[QMB]、[MAG]、[V/M] 功能。本章先逐键说明，再给出话筒、耳机与电键的接线定义（8 针话筒插座、φ3.5 耳机插 座、3 触点电键插座），最后给出键控接线的注意事项。
10-1 Microphone Switches · 话筒按键
PTT Switch 切换发射 / 接收：按下即发射，松开即接收。 发射键 Switches Transmit/Receive. Press to transmit and release to receive.
[UP] / [DWN] 可用 [UP]/[DWN] 键手动向上或向下扫描频率。 上 / 下键 The [UP]/[DWN] keys may also be used to manually scan the frequency upward or downward.
MUTE 按住 MUTE 键期间，扬声器输出的接收音频会被静音。 静音键 While pressing the MUTE key, the receiver audio from the speaker will be muted.
Microphone 用正常音量说话，话筒距嘴部 5 cm。 话筒单元 Speak into the microphone in a normal tone of voice with the microphone 5 cm away from the mouth.
P1 切换 MAIN DIAL 旋钮与 SUB DIAL 的 ON/OFF 锁定。锁定（Lock）开启时，MAIN 或 SUB 旋钮仍可 可编程键 1：旋钮锁定 旋转，但频率不会改变，屏幕显示 "LOCK"。该键与电台前面板的 [Power] 键功能相同。 Toggles the ON/OFF lock for the MAIN Dial knob and the SUB Dial. When "Lock" is ON, the MAIN or SUB Dial knob can still be turned, but the frequency will not change, and "LOCK" appears in the display. Same function as the [Power] key on the front panel.
P2 把当前操作状态一键存入专用存储频道（QMB：Quick Memory Bank）。该键与电台前面板的 [QMB] 可编程键 2：QMB 键功能相同。 The current operation status can be stored in a dedicated memory channel (QMB: Quick Memory Bank) with one touch. Same function as the [QMB] key on the front panel.
P3 短按该键切换到更高的工作频段。该键与电台前面板的 [MAG] 键功能相同。 可编程键 3：频段切换 Pressing this key momentarily changes to a higher Operation Band. Same function as the [MAG] key on the front panel.
P4 切换频率控制方式，在 VFO 与存储系统之间切换。该键与电台前面板的 [V/M] 键功能相同。 可编程键 4：VFO / 存 Toggles frequency control between VFO and the memory system. Same function as the [V/M] key on the front 储切换 panel.
表 10-1 SSM-75E 话筒按键与前面板对应关系 Table 10-1 SSM-75E keys and their front-panel equivalents
话筒按键 对应前面板控件 功能 Mic key Front-panel equivalent Function
PTT – 按下发、松手收
[UP] / [DWN] – 手动向上 / 向下扫描频率
MUTE – 按住时扬声器接收音频静音
P1 前面板 [Power] 键 MAIN DIAL / SUB DIAL 锁定开关，锁定时屏幕显示 LOCK
P2 前面板 [QMB] 键 一键存入 QMB
P3 前面板 [MAG] 键 切换到更高的工作频段
P4 前面板 [V/M] 键 VFO 与存储系统切换
HAM 实战 · 技术提示 FIELD NOTE
手持话筒说话时把嘴保持在约 5 cm（两指宽）、略微偏轴 15~30 度，可以明显减少爆破音（p、t 气流冲击）造成的过调 制。如果对方反映你的声音发闷或断续，先调整距离和角度，再去动 [MIC GAIN]。（社区经验） Hold the mic about 5 cm from your mouth and keep it 15–30 degrees off-axis: this markedly reduces plosive blasts from p and t sounds. If the other station reports a muffled or choppy signal, adjust distance and angle before touching [MIC GAIN]. (community-reported)
避坑指南 PITFALL
话筒上的 P1 与前面板电源键同功能，但它是“短按即切换锁定”，不会关机——不必担心误触关机。真正的坑是：P1 打开锁 定后旋钮仍在自如旋转，只有频率不变，用户往往误判为旋钮故障。屏幕上出现 "LOCK" 即是锁定，再按一次 P1 解除。（社 区经验） P1 on the microphone shares the power key's function but only toggles the lock — a tap will not power the radio down, so there is no risk of an accidental shutdown. The real trap: with the lock on, the dial still turns freely and only the frequency refuses to move, which users often misread as a broken dial. A "LOCK" indication on screen means it is engaged; tap P1 again to release it. (community- reported)
10-2 Microphone, Headphone, Key and Keyer Connections · 话筒、耳机与电键接线
MIC 插座为 8 针插座，接受采用传统 YAESU 短波机针脚 The MIC jack is an 8-pin jack that accepts input from a 定义的话筒输入。PHONE 为标准的 φ3.5 立体声插座，插 microphone utilising the traditional YAESU HF transceiver 入耳机插头后内部扬声器与外接扬声器均会自动断开。 pinout. The PHONE jack is a standard φ3.5 stereo jack; KEY 插座为 3.5 mm、3 触点插座，可接 CW 电键或电子 inserting a headphone plug into it deactivates the internal 键桨，该插座不能使用两触点（两芯）插头。 and external speakers. The KEY jack is a 3.5-mm, 3-contact jack that accepts a CW key or keyer paddle; a two-contact plug cannot be used in this jack.
表 10-2 话筒（MIC）8 针插座针脚定义 Table 10-2 MIC 8-pin jack pinout
针脚 用途 Pin Use
FAST 话筒 FAST 键信号
GND 地
PTT 发射键控
MIC 话筒音频输入
MIC GND 话筒音频地
+5V +5 V 供电
UP UP 键信号
DOWN DOWN 键信号
表 10-3 耳机（PHONE）与电键（KEY）插座 Table 10-3 PHONE and KEY jacks
插座 规格 触点定义 Jack Type Contacts
PHONE 标准 φ3.5 立体声 GND / AUDIO / AUDIO；插入耳机插头后内部与外接扬声器均断开
KEY 3.5 mm、3 触点 KEY / NC / GND；电子键桨接线时使用 DOT / DASH / COMMON 标 记；键抬起电压 +5.0 V DC，按下电流 3 mA
10-3 Keying Connection Notes · 键控连接要点
连接单杆键（straight key）时，电键把键控线对地闭合； When connecting a single straight key, the key closes the 连接电子键桨（keyer paddle）时，使用 DOT、DASH 与 keying line to ground. When connecting an electronic COMMON 三处触点。两种情况下的键抬起电压均为 keyer paddle, the DOT, DASH and COMMON contacts are +5.0 V DC，按下电流均为 3 mA；该插座不能使用两触 used. In both cases the key-up voltage is +5.0 V DC and 点（两芯）插头。 the key-down current is 3 mA; a two-contact plug cannot be used in this jack.
注意 NOTE
使用话筒时请注意：插入耳机插头会自动断开内部扬声器与外接扬声器（原厂说明）。若你使用外接扬声器监听，又插入了耳 机，声音会全部转到耳机侧。 Note that inserting a headphone plug into the PHONE jack deactivates both the internal and the external speaker. If you monitor through an external speaker and then plug in headphones, all audio moves to the headphones.
技术提示 TIP
自制或更换话筒时，先按表 10-2 核对 FAST / PTT / MIC / MIC GND / +5V / UP / DOWN 七个信号线的位置，尤其不要接 错 +5V 与 MIC GND——接错会同时损坏话筒和电台的偏置电路。使用原厂 SSM-75E 时无需担心此问题。 If you build or replace a microphone cable, check the FAST / PTT / MIC / MIC GND / +5V / UP / DOWN signals against Table 10-2 first — in particular never swap +5V and MIC GND, which can damage both the microphone and the radio's bias circuit. With the stock SSM-75E this is not an issue.
PART III
第三部分接收、频谱与干扰抑制 Reception, Spectrum & Interference
决定一台 SDR 收发信机好不好用的，从来不是发射功率，而是接收链路的调理能力。这一部分讲清 ATT / IPO / AMP / AGC 的判据、频谱屏的全部设置，以及 DSP 干扰抑制的取舍。
11 重要接收设置 Important Receiver Settings
12 频谱屏信息详解 Information on the Scope Screen
13 频谱显示设置 Scope Display Setting
14 PMG 主存储组（VHF/UHF） PMG (Primary Memory Group)
15 DSP 干扰抑制功能 DSP Interference Removal Functions
16 双频接收与 Split 操作 Dual Receive & Split Operation