The number of FM transmitting stations which need the narrow band width BPF and the narrow frequency separation combiner has increased recently. In this paper, required amplitude response and group delay on the frequency of these equipment are analysed by computer simulation. These analysis are very useful for designing the FM transmitting equipment with exellent characteristics.
In order to transistorize 300〜500kW Medium-Wave radio transmitters, we have developed 12kW Medium-Wave Power Amplifier by using new type of SITS with two times breakdown voltage, and power capacity compared to conventional SITs used in 20〜100kW radio transmitters. This new power amplifier has Drain-efficiency of 85% (at 800kHz) and power gain of 16dB.
In order to realize practical HDTV transmission via satellite, NTV has introduced HDTV digital Codec. Using this equipment, the HDTV signals are compressed into 60 Mbps bit stream, modulated using QPSK, and transmitted via communication satellite with 36 MHZ band-width. We have started experimental digital transmission and measured the characteristics of transmission path at a field test. In this paper, we introduce an outline of our HDTV digital transmission system. Also we describe the result of the measurement test.