据我了解，CW应该是一种独立的调制方式，就是只有载波，按下电键时发射载波，不按电键时什么都不发射。我用的是 YAESU FT-450D，我发现调整模式的时候，屏幕上会同时显示 USB 和 CW，所以就有个疑问了，这调制方式 USB 和 CW 应该是互斥的呀，是 USB 模式就不是 CW，是 CW 就不是 USB 才对，为什么他们会同时显示，难道是用 USB 调制方式发射了等幅电报？注：我说的用 USB 调制方式发射等幅电报的意思是实际的调制方式是 USB，只不过传递的内容是“滴”的声音而已；用 CW 调制方式发射是指只是发射了载波，没有调制波，接收端收到的“滴”声音是接收端根据接收到的载波自动播放的。

没有本质区别吧，usb在f频率上发射一个频率为f1单音信号也就相当于发射f+f1的cw信号没设备，纯嘴炮😄

请看说明书 [upl-image-preview url=https://storage.hamcq.cn/2024-05-31/1717136918-201362-image.png]

1楼应该就是正确答案。其实对比一下声音的频谱和USB语音的频谱就能发现，USB其实就是把原始信号原封不动的移动到其他频率（所以那些数字模式虽然都是FSK，PSK之类的，电台上的数字传输模式也要设置成USB）。可以尝试一下直接用USB接收CW信号，稍微移动一下接收频率，就会发现USB和CW之间相差的频率就是听到的侧音频率。

@"BloodBlade"#p19288 余老在这个帖子里有很好的解答：https://www.hellocq.net/forum/read.php?tid=305674 [upl-image-preview url=https://storage.hamcq.cn/2024-05-31/1717142297-698069-image.png] [upl-image-preview url=https://storage.hamcq.cn/2024-05-31/1717142330-230303-image.png] 用SSB模式接收CW信号，实际上是用SSB的差拍系统“还原”出一个频率为差频的音频信号

我懂了，CW 既是一种调制方式也是一种模式（这里的调试方式指的是 FM、AM、SSB 这一类，模式指的是 PH、SSTV 这一类），传统的调制方式和模式都是 CW，现在的单边带机器调制方式使用了 SSB，模式用了 CW。

Could you please explain why both USB and CW are displayed simultaneously?

BG2KUJ

As far as I understand, CW (Continuous Wave) should be an independent modulation method, meaning that only the carrier wave is transmitted when the key is pressed, and nothing is transmitted when the key is not pressed.

I'm using a YAESU FT-450D, and I've noticed that when I adjust the mode, both USB and CW are displayed on the screen simultaneously. This makes me wonder: shouldn't USB and CW be mutually exclusive modes? Shouldn't it be that if one is active, the other isn't? Why are they both showing up at the same time? Is it possible that I'm transmitting using the USB mode while also sending a CW signal?

Note: When I say "using USB modulation to transmit Morse code," I mean that the actual modulation method is USB, but the content being transmitted is simply the sound of "dit." Using CW (Continuous Wave) modulation means only the carrier wave is transmitted; there is no modulation. The receiving end receives the "dit" sound automatically based on the received carrier wave.

BD7PRI

There doesn't seem to be a fundamental difference; transmitting a single-tone signal at frequency f on a USB channel is equivalent to transmitting a continuous wave (CW) signal with a frequency of f1.
No equipment; purely verbal.😄

BG6QED

Please refer to the instruction manual.

BloodBlade

The first floor should definitely be the correct answer.

In fact, by comparing the spectrum of the sound and the spectrum of USB audio, you can see that USB essentially moves the original signal to a different frequency without any modification (which is why even digital modes like FSK and PSK used in radio transmission need to be configured for USB).

You can try directly receiving CW signals via USB, and by slightly adjusting the receiver frequency, you'll find that the difference in frequency between USB and CW is the frequency of the side tone.

BG6QED

BloodBlade Mr. Yu provides excellent answers in this post:https://www.hellocq.net/forum/read.php?tid=305674

When receiving CW signals in SSB mode, this essentially involves using the SSB's beat frequency system to "reconstruct" an audio signal with a frequency equal to the beat frequency.

BG2KUJ

I understand. CW is both a modulation method and a mode (when referring to debugging, this means FM, AM, SSB, etc.; when referring to modes, it means PH, SSTV, etc.). Traditional modulation methods and modes are all CW, while the current single-sideband machine uses SSB for modulation, and CW for modes.

闽ICP备2021006864号-7

闽公网安备35020602002794号互联网举报中心

用户协议隐私政策社区规范积分规则中继规则转载须知
更新日志联系我们常见问题友情链接运营报告赞助

浩奇科技（厦门）有限公司

是无线电，把我们联系在一起