笔者已在《无线通信技术》(1980年第4期)上发表了“国外短波中功率单边带发射机发展现状与趋向”文章,本文是在此基础上撰写的续篇。考虑大中功率两种发射机在技术发展上基本相同,故标题改用现名。前文已介绍短波单边带通信设备与其他通信设备比较具有辐射功率小、体积小、耗电省、使用灵活、便于机动、构成电路简单和成本低的特点。虽然六十年代出现了卫星通信、海缆通信以及其他新的通信手段,但是,短波单边带通信除大功率电台日渐减少外,中小功率电台依然有其存在和发展的价值。尤其在军用通信方面,由于短波通信系统的抗毁力和机动性都比较强,即使被摧毁也是个别线路;并且由于设备简单经济,电路中断后能很快恢复,所以在现代战争条件下它仍然是生命力比较强的一种通信手段。由于短波频段窄,电台拥挤,相互干扰严重,而且在传播过程中,电离层有年、月日时的变化,再加上太阳黑子活动与磁暴现象等的干扰,因此,通信很不稳定,通信质量差(误码率通常达10~(-2)～10~(-3)量级),有时甚致使通信中断。如何改进单边带收、发信机的性能,提高短波单边带通信的质量,则是当前国外研究的主要课题。根据近年来国外大中功率单边带发射机的发展趋向加以综合并阐述如下: The author has published an article entitled “Development Status and Trend of Shortwave Medium-Power Single Sideband Transmitters Abroad” in “Wireless Communication Technology” (Issue 4, 1980), which is a sequel to this article. Consider medium and large power transmitters are basically the same in technology development, so the title switch to the present name. Earlier, it has been introduced that the shortwave single sideband communication device has the characteristics of small radiation power, small size, low power consumption, flexible use, easy maneuver, simple circuit configuration and low cost as compared with other communication devices. Although satellite communication, submarine cable communication and other new means of communication have emerged in the 1960s, short-wave single-sideband communication has its value in existence and development except high-power radio stations. Especially in the area of ​​military communications, shortwave communication systems are relatively powerful and maneuverable even if they are destroyed, and because the equipment is simple and economical, the circuit resumes soon after the interruption of the circuit, so under modern warfare conditions it remains Is a relatively viable means of communication. Due to the narrow frequency band of the short wave, the radio station is crowded and the mutual interference is serious. In the process of propagation, the ionosphere has the changes of year, month and day, and the interference of sunspot activity and magnetic storms. Therefore, the communication is unstable and the communication Poor quality (bit error rates typically on the order of 10 -2 to 10 -3), sometimes disrupting communications. How to improve the performance of single-sideband receiver and transmitter and improve the quality of shortwave single-sideband communication are the main topics of current foreign research. According to the development trend of foreign medium and large power single-sideband transmitters in recent years, the following is summarized and described as follows: