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1.前言在TV电话等图像信号的数字传输中,DPGM是极为有效的带宽压缩编码方式,过去已做过各种研究(1)(2).在DPCM等差分编码方式中,编解码器上都要用到积分器,但如果收发两端的积分器特性不配,那么由此引起的误差就要积累从而大大降低画质.特别是模拟式积分器,收发两端容易产生特性不匹配现像.而如果积分器采用数字形式,积分器不匹配的缺点在本质上就可以完全克服.然而,若使数字积分式DPCM全部数字化,则发端就需要有高成本,高精度的A/D变换器,而且会使装置规模增大,因此,做为没有因为积分器不匹配引起的图像质量变坏,成本低,体积小
1. Introduction In the digital transmission of image signals such as TV telephone, DPGM is an extremely effective bandwidth compression coding method, and various studies have been done in the past (1) (2). In DPCM and other differential coding methods, the codec Should use the integrator, but if the integrator at both ends of the transceiver characteristics do not match, then the resulting error will be accumulated to greatly reduce the quality, especially the analog integrator, send and receive characteristics prone to mismatch phenomenon. However, if the integrator is in digital form, the disadvantages of the integrator mismatch can be completely overcome in nature.However, if the digital integrated DPCM is all digitized, then the originator needs a high-cost, high-precision A / D converter, But also increases the size of the apparatus, and therefore, as the image quality is not deteriorated due to the integrator mismatch, the cost is low, the volume is small