In the field of Factory Automation (FA), process control, and Supervisory Control and Data Acquisition (SCADA), an analog data acquisition system using isolation transformers is commonly used to measure and record analog signals through isolated inputs. In order to improve the input precision of the acquisition system, circuit techniques and a design method of the analog frontend circuit with the signal transformers are proposed in this paper. A circuit technique to compensate for the droop of the pulse signal due to the characteristics of the signal transformer is employed. Also, a numerical analysis of a non-linear circuit equation, which represents a behavior of the core saturation of the signal transformer, is performed in order to determine the parameters of the circuit. Using a small signal transformer, dedicatedly developed for this acquisition system, the performance of the precision achieved for the linearity error is experimentally confirmed within +0.0204%/-0.0215%.

A novel asymmetric tapered-line power divider is presented. It has several strip resistors which are formed like a ladder between the tapered-line conductors to achieve a good output isolation. The equivalent circuits are derived with the even/odd-mode analysis. These equivalent circuits are employed to design the asymmetric power divider. The fabricated asymmetric power divider with 1:2 power dividing ratio shows broadband performances in return loss and isolation which are greater than 19 dB over a 3:1 bandwidth in the C-Ku bands.

Computing devices have reached data frequencies of 100 MHz, and have created a need for small-amplitude impedance-matched buses. We simulated signal transmission characteristics of two basic driver circuits, push-pull and open-drain,for a synchronous DRAM I/O bus. The push-pull driver caused less signal distortion with parasitic inductance and capacitance of packages, and thus has higher frequency limits than the open-drain GTL type. We describe a bus system using push-pull drivers which operates at over 125 MHz. The bus line is 70 cm with 8 I/O loads distributed along the line, each having 25 nH7pF parasitic inductance and capacitance.