Statistical Power Analysis Features Added to Giga-Tronics 8560A Series Universal Power Meters

Giga-tronics Inc. (San Ramon, CA) added significant new features to its 8650A Series Universal Power Meters, including histograms, CDF/CCDF and stripchart capabilities. The 8650A Series Universal Power Meters are available in single and dual channel configurations. They have the extensive measurement capabilities and features required to measure the peak and average power of TDMA, GSM, and CDMA (IS-95 and Third-Generation) signals. They also have the capability to measure CW and pulse modulated signals with NIST traceable accuracy from 10 MHz to 40 GHz over a –70 to +47 dBm range.

The histogram function allows the user to view a power range distribution over a period of time. The x-axis displays the minimum to maximum power levels measured during the specified time interval, and the y-axis displays the percent of time each power level is measured. A zoom feature lets the user view smaller segments of the power range to better analyze the percentage of time a specific power level has occurred. The histogram function is used in conjunction with the average mean power level and the crest factor to determine optimum design criteria. This can prevent inadequate performance due to under design or excessive cost due to over design.

The Cumulative Distribution Function (CDF) shows the percentage of time a signal is below a selected power level. The x-axis displays the amount of power at the selected level, measured in dBm, and the y-axis displays the percentage of time the power is at or below the power specified by the x-axis. The Complementary Cumulative Distribution Function (CCDF) reorients the CDF curve in accordance with the equation CCDF = 1-CDF for more accustomed viewing of a descending slope. Moving a cursor along the slope of the curve displays the power level in dBm and the corresponding percentage of time the signal is above that level. Both CDF and CCDF provide further analysis of data presented in the histogram to assist in determining optimum design criteria.

The strip chart function allows the user to view the varying power levels of a signal over a period of time. The x-axis displays time from the start of the measurement to a selectable period of 1 to 200 minutes, and the y-axis displays the minimum to maximum power levels measured during the selected period. Moving a cursor along the x-axis displays time and the corresponding power level.

U.S. list price is $3,310 for an 8651A single channel model and $4,870 for a two-channel model 8652A. The new features are included in all 8650A Universal Power Meters shipped after December 3, 1999. Present owners of 8650A meters can download the new features, free of charge, from the Giga-tronics web site. For more information, call Giga-tronics at 1-800-726-4442.