DSP 干扰抑制功能 15 CHAPTER DSP Interference Removal Functions
本章要点：FTX-1 的 DSP 干扰抑制功能集中在 [MAIN] / [SUB] 旋钮上：按住旋钮后旋转，即可在 SHIFT、WIDTH、NOTCH、 CONTOUR、APF 之间切换并逐项细调。本章逐项说明这五个功能的作用、操作步骤、可调范围与相关菜单，并给出"多个 DSP 功能叠加反而更差"的取舍原则。
按住 [MAIN] 或 [SUB] 旋钮，然后旋转该旋钮，即可在 Press and hold the [MAIN] or [SUB] knob, then rotate the SHIFT、WIDTH、NOTCH、CONTOUR、APF 之间切 [MAIN] or [SUB] knob to exchange the SHIFT, WIDTH, 换。"MAIN" 侧用 [MAIN] 旋钮设置，"SUB" 侧用 [SUB] NOTCH, CONTOUR and APF. The “MAIN” side is set with 旋钮设置。 the [MAIN] knob, and the “SUB” side is set with the [SUB] knob. 以下说明以 "MAIN" 侧的设置为例。要设置 "SUB" 侧，请 用 [SUB] 旋钮执行相同的操作。 The following explanation describes how to set up the “MAIN” side. To set up the “SUB” side, perform the same operation using the [SUB] knob.
15-1 Setting method · 通用设置步骤
1. 按住 [MAIN] 旋钮，或触摸频谱区域。 1. Press and hold the [MAIN] knob or touch the spectrum 2. 旋转 [MAIN] 旋钮选择功能，然后按下 [MAIN] 旋 area. 钮。（也可通过触摸功能名称来选择。） 2. Rotate the [MAIN] knob to select the function, then 3. 旋转 [MAIN] 旋钮设定所需数值。 press the [MAIN] knob. (The function may also be selected by touching the function name.) 4. 按下 [MAIN] 旋钮确认设置。
3. Rotate the [MAIN] knob to set the desired value. 在设置 DSP 干扰抑制功能（SHIFT、WIDTH、NOTCH、 4. Press the [MAIN] knob to confirm the setting. CONTOUR、APF）时按住 [BACK] 键，该设置将恢复为 默认值。 Press and hold the [BACK] key while setting the DSP interference removal function (SHIFT, WIDTH, NOTCH, CONTOUR, APF), and the setting will return to the default value.
15-2 SHIFT · SHIFT（中频移位）
IF SHIFT（中频移位）允许在不改变输入信号音调的前提 IF SHIFT permits moving the digital filter passband higher 下，把数字滤波器通带向高处或低处移动，从而减轻或消 or lower, without changing the pitch of the incoming 除干扰。由于调谐的载波频率并未改变，因此无需重新调 signal, and thus reduce or eliminate interference. Because 谐工作频率即可消除干扰。IF SHIFT 系统的通带总调谐范 the tuned carrier frequency is not varied, there is no need 围为 ±1.2kHz。 to re-tune the operating frequency to eliminate the interference. The total passband tuning range for the IF SHIFT system is ±1.2kHz.
操作步骤 Setup Procedure
1. 按住 [MAIN] 旋钮。 1. Press and hold the [MAIN] knob. 2. 旋转 [MAIN] 旋钮选择 "SHIFT"，然后按下 [MAIN] 2. Rotate the [MAIN] knob to select “SHIFT”, then press 旋钮。（也可通过触摸 "SHIFT" 来选择。） the [MAIN] knob. (The function may also be selected 3. 向左或向右旋转 [MAIN] 旋钮，以减轻干扰信号。 by touching “SHIFT”.) 4. 按下 [MAIN] 旋钮保存设置。 3. Rotate the [MAIN] knob to the left or right to reduce interfering signals. 按住 [BACK] 键可快速把滤波器通带移回中心。把滤波器 4. Press the [MAIN] knob to save the setting. 通带移动到使干扰落在通带之外，即可降低干扰电平。
Press and hold the [BACK] key to quickly move the filter passband to center. Moving the filter passband so that the interference is outside of the passband reduces the interference level.
15-3 WIDTH · WIDTH（中频带宽）
IF WIDTH（中频带宽）调谐系统允许改变 DSP 中频通带 The IF WIDTH tuning system allows you to vary the width 的宽度，以减轻或消除干扰。此外，当波段干扰很小、希 of the DSP IF passband, to reduce or eliminate interference. 望提升输入信号保真度时，也可以把带宽从默认设置展 Moreover, the bandwidth may actually be expanded from 宽。 its default setting, should you wish to enhance incoming signal fidelity when interference on the band is low.
1. 按住 [MAIN] 旋钮。旋转 [MAIN] 旋钮选择 1. Press and hold the [MAIN] knob. Rotate the [MAIN] "WIDTH"，然后按下 [MAIN] 旋钮。（也可通过触摸 knob to select “WIDTH”, then press the [MAIN] knob. "WIDTH" 来选择。） (The function may also be selected by touching 2. 逆时针旋转 [MAIN] 旋钮可收窄带宽、减轻干扰。 “WIDTH”.) 3. 按下 [MAIN] 旋钮保存设置。 2. Rotate the [MAIN] knob counter-clockwise to narrow the bandwidth and reduce interference. 按住 [BACK] 键可将数字滤波器带宽复位到初始值。默认 3. Press the [MAIN] knob to save the setting. 带宽及总带宽调整范围随工作模式而不同。
Press and hold the [BACK] key to reset the digital filter bandwidth to its initial value. The default bandwidths, and total bandwidth adjustment range, will vary according to the operating mode.
表 15-1 各模式的 IF BANDWIDTH 范围与默认值 Table 15-1 IF BANDWIDTH range and default by operating mode
工作模式 默认值 IF BANDWIDTH Operating Mode Default
LSB / USB 300Hz – 4000Hz 3000Hz
CW-L / CW-U 50Hz – 4000Hz 500Hz RTTY-L / RTTY-U
DATA-L / DATA-U 50Hz – 4000Hz 3200Hz PSK
AM 9000Hz（固定） 9000Hz
AM-N 6000Hz（固定） 6000Hz
15-4 NOTCH · NOTCH（中频陷波）
IF NOTCH 滤波器是一套高效系统，可把接收通带内的干 The IF NOTCH filter is a highly effective system that allows 扰差拍音或其它载波信号消除掉。 removing an interfering beat note or other carrier signal 1. 按住 [MAIN] 旋钮。 from within the receiver passband. 2. 旋转 [MAIN] 旋钮选择 "NOTCH"，然后按下 [MAIN] 1. Press and hold the [MAIN] knob. 旋钮。（也可通过触摸 "NOTCH" 来选择。） 2. Rotate the [MAIN] knob to select “NOTCH”, then press 3. 旋转 [MAIN] 旋钮，调整陷波滤波器的"零点"位置。 the [MAIN] knob. (The function may also be selected by touching “NOTCH”.) 4. 按下 [MAIN] 旋钮保存设置。 3. Rotate the [MAIN] knob to adjust the “null” position of 按住 [BACK] 键可使中心频率回到初始值。 the Notch filter. 4. Press the [MAIN] knob to save the setting.
Press and hold the [BACK] key to return the center frequency to its initial value.
陷波滤波器的带宽（窄或宽）可通过菜单项 [OPERATION The bandwidth of the NOTCH filter (either narrow or wide) SETTING] → [RX DSP] → [IF NOTCH WIDTH] 调整。出 may be adjusted using Menu item [OPERATION SETTING] 厂默认设置为 "WIDE"。 → [RX DSP] → [IF NOTCH WIDTH]. The factory default setting is “WIDE”. 旋转 [MAIN] 旋钮可使陷波点在通带内移动；当零点正好 落在输入的差拍音上时，陷波效果最佳。 Rotating the [MAIN] knob moves the notch through the passband; the notching effect is at its maximum when the null is placed exactly on the incoming heterodyne.
15-5 CONTOUR · CONTOUR（通带整形）
CONTOUR 滤波器系统对中频滤波器通带进行平缓的整 The CONTOUR filter system provides a gentle perturbation 形。通过设定 CONTOUR 来抑制或提升特定的频率成分， of the IF filter passband. The CONTOUR is set to either 从而改善接收信号的声音与可读性。 suppress, or boost specific frequency components, and thus enhances the sound and readability of a received "CONTOUR" 功能在 CW-L 与 CW-U 模式下不起作用。
signal.
The “CONTOUR” function does not work in CW-L and CW- U modes.
1. 按住 [MAIN] 旋钮。 1. Press and hold the [MAIN] knob. 2. 旋转 [MAIN] 旋钮选择 "CONTOUR"，然后按下 2. Rotate the [MAIN] knob to select “CONTOUR”, then [MAIN] 旋钮。（也可通过触摸 "CONTOUR" 来选 press the [MAIN] knob. (The function may also be 择。） selected by touching “CONTOUR”.) 3. 旋转 [MAIN] 旋钮，使输入信号的音频重放最为自 3. Rotate the [MAIN] knob to achieve the most natural- 然。 sounding audio reproduction of the incoming signal. 4. 按下 [MAIN] 旋钮保存设置。 4. Press the [MAIN] knob to save the setting. 按住 [BACK] 键可使中心频率回到初始值。 Press and hold the [BACK] key to return the center frequency to its initial value.
调整 CONTOUR 的 GAIN（增益）
Adjusting the GAIN of the CONTOUR Circuit
1. 按住 [FUNC] 旋钮。 1. Press and hold the [FUNC] knob. 2. 选择 [OPERATION SETTING] → [RX DSP] → 2. Select [OPERATION SETTING] → [RX DSP] → [CONTOUR LEVEL]。 [CONTOUR LEVEL]. 3. 旋转 [FUNC] 旋钮，或触摸数值两侧的 "<" 或 ">"， 3. Rotate the [FUNC] knob, or touch “<” or “>” on either 设定 CONTOUR 电路的增益。 side of the value to set the CONTOUR circuit gain. 4. 按下 [FUNC] 旋钮，或等待约 3 秒，即保存设置。 4. Press the [FUNC] knob, or wait for about 3 seconds to save the setting. 5. 连按 [BACK] 键数次，回到正常工作状态。
5. Press the [BACK] key several times to return to normal operation.
设定 CONTOUR 的带宽（"Q"） Sets the Bandwidth (“Q”) of the CONTOUR Circuit
1. 按住 [FUNC] 旋钮。 1. Press and hold the [FUNC] knob. 2. 选择 [OPERATION SETTING] → [RX DSP] → 2. Select [OPERATION SETTING] → [RX DSP] → [CONTOUR WIDTH]。 [CONTOUR WIDTH]. 3. 旋转 [FUNC] 旋钮，或触摸数值两侧的 "<" 或 ">"， 3. Rotate the [FUNC] knob, or touch “<” or “>” on either 设定 CONTOUR 电路的带宽（"Q"）。 side of the value to set bandwidth (“Q”) of the 4. 按下 [FUNC] 旋钮，或等待约 3 秒，即保存设置。 CONTOUR circuit. 4. Press the [FUNC] knob, or wait for about 3 seconds to 5. 连按 [BACK] 键数次，回到正常工作状态。 save the setting. 5. Press the [BACK] key several times to return to normal operation.
15.6 APF（音频峰值滤波器） APF
在 CW 操作中，当存在干扰或噪声时，中心频率会自动设 During CW operation, when interference or noise is 定到 PITCH（音调）频率，从而更容易听清目标信号。 present, the center frequency is automatically set to the "APF" 功能仅在 CW-L 与 CW-U 模式下起作用。 PITCH frequency, making it easier to hear the desired signal.
The “APF” function only works in CW-L and CW-U modes.
1. 按住 [MAIN] 旋钮。 1. Press and hold the [MAIN] knob. 2. 旋转 [MAIN] 旋钮选择 "APF"，然后按下 [MAIN] 旋 2. Rotate the [MAIN] knob to select “APF”, then press the 钮。（也可通过触摸 "APF" 来选择。） [MAIN] knob. (The function may also be selected by 3. 向左或向右旋转 [MAIN] 旋钮，以减轻干扰。 touching “APF”.) 4. 按下 [MAIN] 旋钮保存设置。 3. Rotate the [MAIN] knob to the left or right to reduce any interference. 5. 按住 [BACK] 键，可将 APF 峰值中心频率设置恢复为
4. Press the [MAIN] knob to save the setting. "0Hz"，并关闭 APF 功能。
5. Press and hold the [BACK] key to restore the APF peak APF 带宽可通过菜单项 [OPERATION SETTING] → [RX center frequency setting to “0Hz”, and disable the APF DSP] → [APF WIDTH] 从 NARROW / MEDIUM / WIDE function. 中选择。 The APF bandwidth can be selected from NARROW / MEDIUM / WIDE via the Menu item [OPERATION SETTING] → [RX DSP] → [APF WIDTH].
15-7 Related menu items and other noise functions · 相关菜单与其它抑噪功能
表 15-2 DSP / 抑噪相关菜单项 Table 15-2 DSP and noise-related menu items
菜单项 可选值 说明 Menu item Available settings Description
[RX DSP] → [IF NOTCH WIDTH] NARROW / WIDE IF 陷波滤波器带宽，出厂默认 WIDE
[RX DSP] → [APF WIDTH] NARROW / MEDIUM / WIDE APF 带宽
[RX DSP] → [CONTOUR LEVEL] 菜单表记为 -40 – 15 – 0 – 20 CONTOUR 电路增益
[RX DSP] → [CONTOUR WIDTH] 1 – 10 – 11 CONTOUR 电路带宽（"Q"）
[RX DSP] → [NB REJECTION] LOW / MID / HIGH NB（噪声抑制器）的抑制强度
[RX DSP] → [NB WIDTH] NARROW / MEDIUM / WIDE NB 的作用宽度
另有两个噪声处理功能从 [FUNC] 旋钮的功能列表中开 Two further noise functions are switched from the [FUNC] 关：NB 启用 NB（噪声抑制器）功能，DNR 启用 DNR knob function list: NB activates the NB (Noise Blanker) （数字降噪）功能。它们与上述五个 DSP 项目互补：NB function, and DNR activates the DNR (Digital Noise 针对脉冲型噪声，DNR 针对宽带随机噪声，而 SHIFT / Reduction) function. They complement the five DSP items WIDTH / NOTCH / CONTOUR / APF 则作用于中频与音 above: NB is aimed at pulse-type noise, DNR at broad- 频通带内部。 band random noise, while SHIFT / WIDTH / NOTCH / CONTOUR / APF work inside the IF and AF passband.
技术提示 · 多个 DSP 功能叠加反而更差 TIP
DSP 功能不是开得越多越好，每加一级都会带来副作用：①先用"减法"再用"加法"——先收窄 WIDTH、再移 SHIFT，把干扰 挤出通带；这一步能解决七八成的干扰问题，而且不会损伤目标信号。②NOTCH 每开一处都会在通带内挖一个洞，如果目标 信号本身就在洞口附近，声音会立刻变薄、发金属声；只有在干扰音调稳定且远离目标时才用。③CONTOUR 不要一上来就大 增益：先把 CONTOUR WIDTH（Q）设宽、增益设小，逐步收敛到听感最自然的一点；Q 太窄＋增益太大会让语音变得像"机 器人"。④APF 只在 CW-L / CW-U 有效，且它是围绕 PITCH 频率的极窄峰化，开着 APF 扫频找台会非常难受——找到台以 后再开。⑤DNR 级别越高，语音越"水下声"，CW 的节奏感也会被破坏；能听懂就别再往上加。⑥NB 对脉冲噪声有效，但对 密集的宽带噪声几乎无效，反而可能让强信号产生失真。⑦判断标准只有一个：开完之后，把目标信号的"可懂度"和"自然 度"分开评估，可懂度没提升、自然度明显下降的，就关掉。（社区经验） More DSP is not better — every stage you add has a side effect. (1) Work by subtraction before addition: narrow WIDTH first, then move SHIFT to push the interference out of the passband. This solves most interference problems without damaging the wanted signal. (2) Every NOTCH you enable digs a hole in the passband; if the wanted signal sits near that hole the audio immediately becomes thin and metallic. Use NOTCH only when the interfering tone is steady and well away from the target. (3) Do not start CONTOUR with a large gain: set CONTOUR WIDTH (Q) wide and the gain small, then converge gradually on the most natural-sounding point. Too narrow a Q combined with too much gain makes speech sound robotic. (4) APF works only in CW-L / CW-U and is an extremely narrow peaking filter centred on the PITCH frequency; tuning across the band with APF engaged is painful — find the station first, then enable APF. (5) The higher the DNR level, the more "underwater" the speech sounds, and the rhythmic feel of CW is destroyed as well; if you can already copy it, do not raise it further. (6) NB works well against pulse noise but is almost useless against dense broad-band noise, and may distort strong signals. (7) There is only one criterion: after enabling a function, judge intelligibility and naturalness separately. If intelligibility has not improved while naturalness has clearly dropped, switch it off. (community-reported)
注意 · MAIN 侧与 SUB 侧相互独立 NOTE
上述五个 DSP 功能在 MAIN 侧与 SUB 侧是分别设置的：MAIN 侧只能用 [MAIN] 旋钮，SUB 侧只能用 [SUB] 旋钮，两侧的 设置互不影响。做双频接收或 Split 操作时，如果只调了 MAIN 侧，SUB 侧的干扰依旧存在，请记得用 [SUB] 旋钮再调一遍。 The five DSP functions above are set independently for the MAIN and SUB sides: the MAIN side is set only with the [MAIN] knob and the SUB side only with the [SUB] knob, and the two do not affect each other. During dual receive or split operation, adjusting only the MAIN side leaves the interference on the SUB side untouched — remember to repeat the adjustment with the [SUB] knob.