Multifunctional Digital Portable Field Strength Meter

This paper gives a research on the basic functions and their technical target of the CATV field strength meter. Then a multifunctional, digital and portable field strength meter is designed based on this research. This instrument can meter the electric level, frequency spectrum, carry to noise ratio , A/V , cobbly ratio , voltages of the AC trunk line and the battery. Furthermore it can display the above information on the LCD and store them in the EPROM.In this paper, variant metering methods are taken in terms of the different features of the analog signal and the digital signal. The RF signal is attenuated and down converted to intermediate frequency and then transmitted to the digital circuit. The digital circuit of the field intensity indicator is controlled by the single chip computer AT89C55 with the peripheral chips 8155H , TLC1549 , X25645 , MSC-M12864 and MAX232. The signal is processed by the field intensity indicator with the result being displayed and stored. Meanwhile the software of the field strength meter is designed.Compared with the other kinds of field strength meter, this one also has the function to measure the electric level of the digital signal except for the analog one's. It is relatively cheap, multifunctional and small.