Long-distance Transmission of the Multi-channel High-speed Space Camera Data

摘要

In order to solve the problem of the short transmission distance and the high bit-error ratio of multichannel high-speed space camera, an active equalization scheme at the receiver end is proposed and implemented. First of all, the non-dc-balanced characteristics of image data signal is analyzed. Based on the measurement data, the mathematical model of the long transmission cable is created. According to the attenuation characteristics of this model, an equalization circuit is designed, which makes use of the high gain of the high-speed differential amplifier and the frequency selecting feature of the phase-lead feedback network to flatten the frequency response of the lossy transmission channel. The simulation results show that with the equalization circuit the maximum data transfer rate of the channel can be expended from 16 Mbps to 250 Mbps. Besides, the eye diagram measurement results demonstrate that the inter-symbol interference caused by the transmission media is significantly reduced after equalization, resulting in an open eye diagram with reduced jitter and crisp edges. Finally, by observing the Signal Tap logic analyzer, sending grayscale and actual pictures, it has been verified that the error-free transmission distance can reach 80 m at 250 Mbps.