RF power detector/monitor upgrade for the 500 MHz systems at the ALS

Several systems rely on the accurate and linear detection of 500 MHz signals, (the fundamental frequency of both the Booster Ring and Storage Ring) over a dynamic range in excess of 25 dB. Prior to this upgrade, the detector/monitor was diode based and though this type of detector could handle the dynamic range requirement it could not do so in an accurate and linear manner. In order to meet the requirements, (dynamic range greater than or equal to 25 dB, accurate and linear to ±0.25 dB over the range, and additional circuitry to interface to the legacy control system and interlocks) a new RF power detector/monitor has been developed using two AD8361, Analog Devices TruRMS Detectors and a fuzzy comparator, which extends the overall detector´s range to twice that of the AD8361. Further information is available [www.analogedevices.com/]. Details of the design requirements and the detector/monitor´s circuit as well as the performance of the detector will be presented.