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1.引言随着我国广播事业的高速发展,中波广播发射机已经进入了全固态数字化时代,原来广泛使用的电子管板调中波发射机,相继被全固态PDM(脉宽调制)、DAM(数字调幅)中波发射机所代替。全固态数字中波广播发射机具有技术指标好、整机效率高、故障率低等优点,但对工作环境要求相对较高,并且与电子管发射机相比,具有灵敏的驻波比保护电路,以及精确的入、反射功率、天线零位与网络零位表指示等,对天线系统的技术要求
1. INTRODUCTION With the rapid development of China’s broadcasting industry, the medium wave broadcast transmitter has entered the all-solid-state digital era. The originally widely used electronic tube plate modulated wave transmitter has been replaced by all-solid-state PDM (pulse width modulation), DAM Digital amplitude modulation) wave transmitter instead. All-solid-state digital MW broadcast transmitter has the advantages of good technical indicators, high efficiency and low failure rate, but requires relatively high working environment, and compared with the tube transmitter, it has the sensitive VSWR protection circuit, As well as accurate into the reflection power, zero antenna and network zero table instructions, the technical requirements of the antenna system