本规程规定了适用于评估处理ANSI/SMPTE 259M定义的串行数字视频信号的设备低频响应的数字测试信号。这些测试信号是ANSI/SMPTE 125M中定义的完全有效的数字分量视频。它们也是有用的数字复合视频信号，适用于在停止使用模式下测试串行设备。虽然一系列信号将产生所需的低频效果，但定义了两个特定的信号，分别用于测试电缆均衡和锁相环（PLL）锁定。

This practice specifies digital test signals suitable for evaluating the low-frequency response of equipment handling serial digital video signals as defined by ANSI/SMPTE 259M. These test signals are fully valid digital component video as defined in ANSI/SMPTE 125M. They are also useful digital composite video signals suitable for testing serial equipment in an out-of-service mode. Although a range of signals will produce the desired low-frequency effects, two specific signals are defined to test cable equalization and phase locked loop (PLL) lock-in, respectively.