The Design And Research Of Mumberal Attenuator With Multi-controled Funcions

The main role of the attenuators is to lock sky satellite signals by receiving antenna, leading the satellite signals from outdoor into indoor or other areas which can not receive satellite signals. This will be able to use an ordinary satellite receiver to receive satellite signals in room to complete the work which should be done in outdoors for the GPS receiver to provide an adjustable test signals. As a result of the restrict of actual users using the signals range and geographical conditions, we must adjust the signal to the specific region. Meanwhile, many manufacturers in product development and testing process all are in trouble with signal strength, because not all products are based on a fixed signal strength, and therefore attenuator research and development will become very important and the demand of attenuator will increase greatly.This article designs and develops a numberal attenuator with muti-controled function based on the digital attenuation chip technology, equipped with a general instruments of manual controlling,serial interface and display,and GPIB interface to facilitate the computer more conducive to build automation systems.Attenuator on the market today basically is fixed attenuator and rarely has control interface, which caused the process to the actual using of a lot of inconvenience. In this paper, the design of the attenuator, specifically to achieve the innovation are:Firstly, using chip technology plusing microcontroller technology achieve an adjustable attenuation output,no longer a fixed attenuation output. The second,It realizes more control functions, increases manual control interfaces (keyboard interface) and programmable interface (serial interface and GPIB interface) rather than the simple control interface or no control interface.The core chip of the design is NI Company's new attenuator chip-DAT31R5, which is oriented directly to terminal service.This article described the external controlling design of the chip,also gave a number of the matters of specific hardware design; In the keyboard controlling technology, the attenuator has achieved the stabily inputting,which is based on the analysis of the several common controlling algorithms and combined with the keyboard scan processing algorithms based on FSM, and also raised the the efficiency of microcontroller; In the implementation of the LCD display technology, we used a simpler and more practical device-LM16032, and gave the display program correspondly;In the base of making communication agreement,we have accomplished specific design in the serial communication;The article elaborated on common GPIB interface design,and also showed the interface function of GPIB and then gave the process of correspondly functional modules design.The attenuator showed in this article has been putting into using and has a vast market.