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一、概述目前,在电视工程中,一个系统的线性失真通常采用正弦平方脉冲和条波形作为测试信号测出该系统的K指数(K_p、K_(pb)、K_b)来评价。这种方法虽然能使给定的失真与主观图象质量下降相关,但在测量最小失真时就感到困难了,这时就不得不采用传统的幅度/频率和时延/频率的扫频方法。然而,用扫频法需要使用价高而数量多的测试设备,同时测试程序繁琐。更何况电视信号是一种多频率同时传送的复合信号,因而用扫频法测得的结果未必能是直观的最佳效果。为此,我们根据近年来有人提出的一种新的电视测试波形研制出“791型新的电视波形发生器”,它能在电视波形的一个单行上提供所需要的时域(波形法)和频域(频率特性法)测量,测量能够统一起来,一次完成,从而大大简化测量程序、减少设备耗费,并易于直观地评价电视传输系统(同样适用于视频
I. Overview At present, in a television project, a linear distortion of a system is usually evaluated by measuring the K index (K_p, K_ (pb), K_b) of the system by using a square sine pulse and a strip waveform as test signals. Although this method can make a given distortion correlate with the degradation of the subjective image, it is difficult to measure the minimum distortion, at which point conventional amplitude / frequency and sweep / frequency sweep methods have to be used. However, the swept-frequency method requires a high number of test equipment and a large number of test procedures. Moreover, the television signal is a multi-frequency simultaneous transmission of composite signals, so the result of the swept-frequency method may not be the best visual effect. To this end, we have developed “a new TV waveform generator 791” based on a new television test waveform proposed in recent years, which provides the required time domain (waveform method) on a single line of TV waveform and Frequency domain (frequency characteristic method) measurement, measurement can be unified, done at once, which greatly simplifies the measurement procedures, reduce equipment costs, and easy to visually evaluate the TV transmission system (also applies to video