This paper presents a high efficiency Doherty power amplifier suitable for TV band applications. A class AB power amplifier is firstly implemented using a commercial GaN HEMT from Cree Incorporation, achieving a high ...This paper presents a high efficiency Doherty power amplifier suitable for TV band applications. A class AB power amplifier is firstly implemented using a commercial GaN HEMT from Cree Incorporation, achieving a high power-added-efficiency of 77.78% and a 40.593 dBm output power with an associated gain of 21.65 dB. The Doherty amplifier has then been designed following the previous class AB scheme for the main amplifier and a class C scheme for the peak one. This amplifier attained a high power-added-efficiency of 81.94%, a 42.77 dBm output power, an associated gain of 21.32 dB, and an operating frequency bandwidth between 550 and 1000 MHz (58.06% fractional bandwidth) which made it suitable for TV band applications.展开更多
Two communication systems at W-band are introduced, including the system design, the modulation scheme, etc. TV delivery system delivers picture of quality meeting grade 4.5 over 8 km （no rain）. Digital communicatio...Two communication systems at W-band are introduced, including the system design, the modulation scheme, etc. TV delivery system delivers picture of quality meeting grade 4.5 over 8 km （no rain）. Digital communication system is capable of operating at data rates up to 8.448 Mb/s beyond 10 km under a BER of 10^-6 （clear）.展开更多
在珠三角地区对超高频(Ultra High Frequency,UHF)频段开展了近两个月的监测,给认知无线电技术在广东省的应用提供了现实依据.结果表明:频段利用率普遍较低,同一频段在不同地区、不同时段的利用情况存在一定的差异.对广播电视频道占用...在珠三角地区对超高频(Ultra High Frequency,UHF)频段开展了近两个月的监测,给认知无线电技术在广东省的应用提供了现实依据.结果表明:频段利用率普遍较低,同一频段在不同地区、不同时段的利用情况存在一定的差异.对广播电视频道占用情况的建模体现了频道开放时间的规律性;根据各频率点的利用率情况将频率划分为五个占用程度,可得出可供认知无线电用户接入的连续空闲带宽的概率分布.展开更多
文摘This paper presents a high efficiency Doherty power amplifier suitable for TV band applications. A class AB power amplifier is firstly implemented using a commercial GaN HEMT from Cree Incorporation, achieving a high power-added-efficiency of 77.78% and a 40.593 dBm output power with an associated gain of 21.65 dB. The Doherty amplifier has then been designed following the previous class AB scheme for the main amplifier and a class C scheme for the peak one. This amplifier attained a high power-added-efficiency of 81.94%, a 42.77 dBm output power, an associated gain of 21.32 dB, and an operating frequency bandwidth between 550 and 1000 MHz (58.06% fractional bandwidth) which made it suitable for TV band applications.
文摘Two communication systems at W-band are introduced, including the system design, the modulation scheme, etc. TV delivery system delivers picture of quality meeting grade 4.5 over 8 km （no rain）. Digital communication system is capable of operating at data rates up to 8.448 Mb/s beyond 10 km under a BER of 10^-6 （clear）.
文摘在珠三角地区对超高频(Ultra High Frequency,UHF)频段开展了近两个月的监测,给认知无线电技术在广东省的应用提供了现实依据.结果表明:频段利用率普遍较低,同一频段在不同地区、不同时段的利用情况存在一定的差异.对广播电视频道占用情况的建模体现了频道开放时间的规律性;根据各频率点的利用率情况将频率划分为五个占用程度,可得出可供认知无线电用户接入的连续空闲带宽的概率分布.
