There are 64-way analog signals that are respectively connected with the input ports of four highly precise 16-channel analog switches AD7506 whose enabling signal comes from the other decoder 74HC The number of port allotted is 00H-3FH It is provided in the same way as that of the switching signals The highest bit of the signal locked that is valid when low voltage is the decoder’s enabling signal After amplified by highly- precise operational amplifier AD624 and transmitted into voltage of 0-5 V ， the analog output signals are selected by the highly precise 8-channel analog switch AD7501， amplified by isolating amplifier AD290， and transmitted into digital signals by analog-to-digital converter ADC0804， then connected to the data bus The digital signals are obtained by Hoyle sensor monitoring the rotating speed of the host engine in the cabin[1] Hoyle sensor has high measuring It can work reliably in seamy conditions of all kinds and send output digitally Hoyle sensor is connected with the host engine coaxially A counter detects signals from Hoyle sensor that vary with the rotating speed of the host engine So the output of the counter stands for the rotating speed of the host engine， once the counting time length is 64路模拟信号是由4个高精度16通道模拟信号转换芯片AD7506独自连接的输入端口构成，这个转换芯片能处理来自另一种解码芯片74HC138的信号。端口编码为00H-3FH。转换信号也以同样的方式编号。若低电压为解码器工作的允许信号，信号的最高位被锁定是必要的。经过高精度放大器AD624的放大并输入0-5V电压，高精度8通道模拟转换器AD7501选择模拟输出信号（或是翻译成对模拟信号进行取样），再经缓冲放大器AD290放大信号，随后经模数转换器ADC0804作用转换为数字信号，最后与数据总线进行连接。这个数字信号传给霍伊尔传感器以监控船舱内主引擎的转速[1]。霍伊尔传感器拥有较高的测量精度。它在各种恶劣的条件下都能可靠的工作，且以数字形式发送输出数据。霍伊尔传感器与主引擎同轴安装。计数器检测来自霍伊尔传感器的信号，这个信号随主引擎转速而变化。因此一旦计数时长给定，计数器的结果即主引擎的转速。
