在不增加设备体积重量以及提高发射功率的前提下,为满足高码率遥测数据传输的需求,现有的脉冲编码调制-频调(Pulse Code Modulation Frequency Modulation, PCM-FM)遥测系统广泛使用多符号检测(Multiple Symbol Detection, MSD)算法和Turbo乘积码(TPC)技术。调制指数是PCM-FM遥测系统中的重要参数之一,对系统带宽和误码率有重要影响。本文分析了MSD多符号检测算法原理,通过计算互相关系数及Matlab仿真,分析了调制指数大小对带宽和误码率的影响,指出将调制指数设置为0.715较为合适;分析了调制指数偏差对信噪比损耗的影响,利用MSD算法的相位网格图分析了调制指数偏差对误码和码同步的影响,指出随机数据比连“0”或连“1”数据具有更好的容忍能力。
随着“耳朵经济”“声”气蓬勃地发展,无论是泛播客平台还是分众化播客平台都显示出巨大的发展潜力。泛播客与分众化播客“殊途同归”的成功背后暗含着的是二者不同的运营模式,分析二者不同运营模式或可为播客平台差异化竞争提供一些参考。本文藉此分别选取了喜马拉雅与蜻蜓FM作为泛播客与分众化播客的代表案例,分析其在内容运营模式、分发模式、盈利模式等方面的差异,并分析其共有困境与未来发展路径。With the vigorous development of “ear economy”, both general podcasting platforms and niche podcasting platforms have shown great potential for development. Behind the success of general podcasting and niche podcasting, different operation modes are implied, and analyzing the different operation modes of the two may provide some references for the differentiated competition of podcasting platforms. In this paper, Himalaya and Dragonfly FM are selected as the representative cases of pan-podcasting and niche podcasting to analyze their differences in content operation mode, distribution mode, profit model, etc., and analyze their common difficulties and future development paths.
