CSRH的数字光传输

Digital Fiber-Optic Transmission of the CSRH

简述了日像仪高频部分的数字光传输的基本方案及其优点,对于日像仪高频部分(2～15 GHz)太阳信号,分时的变频选出32个5 MHz带宽的窄带所选信号。将此信号采样量化,通过数字光发射与接收设备完成3 km的数据传输功能。在数字光传输过程中,太阳信号经过码型变换、光调制、光纤传输、光解调,再完成码型反变换恢复出太阳信号本身。另外还对光纤数字传输的重要指标作了简要的阐述和计算,如误码率、抖动、漂移等。

This paper presents the basic scheme,configuration,principle,and advantages of the digital fiber-optic transmission in the Chinese Solar Radioheliograph（CSRH）.For reducing costs an RF broadband solar signal in the CSRH high-frequency domain（2GHz-15GHz） is divided into different parts,each of which is converted to a narrow-band signal of a specific frequency.In total 32 bands of signals with a 5MHz bandwidth are chosen from an RF signal and are converted into the IF band for digital sampling.The solar signals are sent to 3km away from the central controlling house by a digital fiber-optic transmission system.In the transmission system,the solar signals are formatted to counter environmental interferences.Through the optical modulation,optical-fiber transmission,and demodulation,the signals are unformatted for the next-step process.In addition,this paper describes some important parameters in the digital fiber-optic transmission,such as the bit-error rate,jitter frequency/amplitude,and fiber-characteristic drift.