数字电视技术不仅已用于电视制式转换器以及录象机和特技信号发生器中的时基校正器,而且已用于帧同步器,以便在多路电视转播时同步电视信号。电视系统中采用的A/D变换器必须性能好、成本低。NHK实验室研制的那些A/D变换器已经达到了这些要求。到目前为止,我们已研制了两种类型的电视用A/D变换器,第一种为8比特A/D变换器,如图1所示,在这种A/D变换器中采用了如下的技术革新: ①采用具有箝位基准电压的电平比较器,用来稳定每一个编码器。②研制了一种具有特别稳定增益的新型简单电路(SRDA),该电路起模拟移位寄存器和减法放 Digital television technology has been used not only for time-base correctors in television format converters and video recorders and trick-play signal generators, but also for frame synchronizers to synchronize television signals during multiplex television broadcasts. A / D converters used in television systems must have good performance and low cost. Those A / D converters developed by NHK Labs have met these requirements. So far, we have developed two types of TV A / D converters, the first for the 8-bit A / D converter shown in Figure 1, in which A / D converter uses the following The technological innovation: ① using clamp reference voltage level comparator, used to stabilize each encoder. ② Developed a new type of simple circuit (SRDA) with a special stable gain, the circuit from the analog shift register and subtraction