The Design Of Device Software Drive Of Measuring Instruments With A GPIB Interface

In order to acquire a sound management of shortwave resource, it is very necessary to assure the allotment of wave band; and the monitoring of shortwave is the first of all steps. At the same time the rapid development of computer technology assures such kind of monitoring can be carried out effectively. While DSP and internet technology introduced into the shortwave monitoring field, we now can monitor a signal at the same at different sites, which makes the locating of a signal more easily than before.To develop a software system of radio monitoring, how to deal with different interface is a problem firstly needing to solve; while there are various interface in measuring instrument industry, such as IEEE 488 standards(GPIB bus), RS232C etc. now the GPIB bus system have a wide use in measurement instruments. Because with such kind of standard interface, a engineer can easily constitute a measuring system. Considering the commercial interest, most instrument manufacture provide measurement instrument with different remote control interface. To make up a radio monitoring system, sometime we need different instrument with different interface. Here arises the problem to deal with different computer-controlled interfaces. How to make the software code morecompatible and more easily to be reused is one of target the software engineer should pursue. In this paper, the author put forward a method to acquire this goal by encapsulating the interface class use C++ ideology. Using this method, the GPIB interface class was designed. Afterwards the author designed a DLL (dynamic link library) as a way of device driver. In this DLL the author included a thread called device-level-thread which mainly deals with the information flow between the device and a controller (usually a computer), while a user-level-thread mainly deals with the display of the sample data on a computer screen. By classifying the measuring function of a device, the device class is also encapsulated in this thread.With a dual-thread mechanic, such method can acquire a satisfactory modularization of software design. An example which can perform the IF analyzer based on the test receiver ESVN40, which has a GPIB remote control interface, was given in the end of this paper.