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目前提供的抑频调制(TFM)数字通信系统,频道间隔为25Kc,传信率16kbit/s。为了减少TFM数字通信系统的量化噪声,改善数字话的质量,提出了改进型的CORPSK(4—5)相关相移键控数字通信系统方案。本文闸述了这种新的数字调制原理,对发射系统中最主要的单元之一——相关编码器(即电平变换器)的设计和实现进行了探讨。所得到的 CORPSK(4—5)电平变换器可直接与预调滤波器级联,为调频发射机提供平滑的相位调制信号。在传信率为32Kbit/s的情况下,可以获得与TFM系统相同的信号带宽(16kc)和波道间隔(25kc)。本文还给出了CORPSK(4—5)电平变换逻辑的计算机模拟結果和程序。
Currently available frequency modulation modulation (TFM) digital communication system, channel spacing of 25Kc, the signaling rate of 16kbit / s. In order to reduce the quantization noise of the TFM digital communication system and improve the quality of the digital speech, an improved CORPSK (4-5) correlation phase shift keying digital communication system solution is proposed. This article describes the new principle of digital modulation, and discusses the design and implementation of one of the most important elements of the transmission system, the associated encoder (level shifter). The resulting CORPSK (4-5) level shifter can be cascaded directly with the pre-filter to provide a smooth phase-modulated signal for the FM transmitter. With a signaling rate of 32 Kbit / s, the same signal bandwidth (16 kc) and channel spacing (25 kc) as the TFM system can be obtained. This paper also gives the CORPSK (4-5) level transformation logic computer simulation results and procedures.