A Wide Dynamic Range Field Strength Meter

Published:2012/11/14 0:37:00 Author:muriel | Keyword: Wide Dynamic Range , Field Strength Meter | From:SeekIC

This unit is an updated version of the Wide Dynamic Range Field Strength Meter. While the basic function is the same, it has several critical differences: It uses a specialized integrated circuit, the Analog Devices AD8307. This chip is designed specifically as a logarithmic amplifier for use through 500 MHz. Using the AD8307, it has a wider dynamic range (85 dB versus 55 dB) and it has built-in temperature compensation. Because of the different nature of this type of detector - and the fact that it has temperature compensation - means that there is no need for a zeroing control. One disadvantage of this approach as compared to the diode approach is that the AD8307 has a lower frequency response than the diode. The frequency limit of the meter is dictated pretty much by the diodes themselves along with their physical layout and related components: There is no reason why the earlier version could not be constructed to work through 10 GHz or so - but the AD8307 is falling flat by the time you get to 1 GHz, making it unsuitable for detecting wireless LANs or PCS-type cell phones.



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