SRM-3000 - Selective Radiation Meter - NARDA - #9

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16 17 SPATIAL AVERAGING How high is the average field exposure determined over the volume of the human body? The SRM averages several spatial values continuously or discretely and displays the result directly at the end of the procedure. MAXIMUM VALUES AND AVERAGES. Where is the field strength highest in the room? At what frequency? When do peak values occur, and how long do they last? The SRM shows all this directly. And if you need to know the average values instead, the SRM shows them, too. THE SRM FROM NARDA: ANALYZES, AVERAGES, AND INTEGRATES. IN FREQUENCY, SPACE, AND TIME. If you need to determine the field strength due to individual wireless services, service providers, or even a single channel, the frequency resolution must be fine enough for the job. The SRM lets you analyze each channel separately in the mobile phone or DECT band without any trouble. If you want to know the total power level in the frequency band, you don’t have to make a new measurement. The integration function will give you the value. Pagers switch on and off without warning, communications channels are used sporadically, so the frequency spectrum is constantly changing. In “Time Analysis” mode, the SRM can record the variation with time down to one-second accuracy, so you can see how individual channels behave over a period of time. With “Time Controlled Storing” (option), you can preprogram a specific starting time and measurement duration. Most standards prescribe time averaging over a six-minute period to determine exposure levels for the human body. The SRM does this automatically, too, regardless of the observation period displayed on the screen. SPECTRUM ANALYSIS: FREQUENCY RESOLUTION AND INTEGRATION. Close to transmitter arrays and in reflecting spaces, the field strength is not distributed evenly. There are definite “hot spots” and minima. To realistically determine how humans are affected, various standards require spatial averaging over a volume corresponding roughly to the human body. The “Spatial Averaging” function of the SRM (option) makes this easy. The measuring antenna is simply moved along the desired path in space for continuous averaging. For discrete averaging, pressing a button adds the measured value at each required point in space. The SRM then averages the values automatically and displays the resulting average value according to IEEE as the end result, for example. SPATIAL AVERAGING: SPATIAL RESOLUTION AND AVERAGING FUNCTIONS. TIME ANALYSIS: TIME RESOLUTION AND TIME AVERAGING. SPECTRUM ANALYSIS How high is the total power level? The integration range can be set just as easily as the zoom range. The numerical result is displayed automatically at the top right of the measurement window. TIME ANALYSIS Past values can be read out using the marker. The so-called duty cycle function automatically determines the ratio of average to maximum power (Pavg/Pmax).