ABSTRACT

Figure 1 shows the block diagram of transponder of BS-3 for Japanese satellite broadcasting. The signal of 14 GHz transmitted from the ground station is received by the parabolic antenna, and it is introduced to a 14-GHz low-noise receiver through the multiplexer. The signal is converted to 12 GHz by the mixer and the local oscillator. Because the signal includes the A, B, and C channels, it is divided by the multiplexer MUP i and amplified by each traveling wave tube. Amplified signals are combined again by the multiplexer and they are supplied to the antenna through the multiplexer. The multiplexer is generally constructed with a combiner and bandpass filters (BPF) of each channel.