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• Dynamic range of 90 dB through innovative multipath SMART SENSOR TECHNOLOGY™
• High measurement speed saves time in manufacturing test
• Sensors retain calibration data in built-in memory, and are immediately ready for measurement
• Accurate measurement of average power regardless of bandwidth and modulation
• Multi-slot measurements for common time division systems (e.g. GSM/EDGE, DECT)
• Intelligent sensors can be operated directly from PC via USB Interface
• Up to 4 sensors can be plugged into the NRP base unit for 4-channel measurements

    Colour Brochure with full specs.  

The NRP RF and Microwave Power Meter is suitable for research and development, production and mobile service as well as the analysis of broadband modulation signals of third-generation mobile radio.

In research applications, the NRP excels with high measurement accuracy and a dynamic range of 90 dB. This applies to broadband signals of any modulation, including RF bandwidths beyond 100 MHz for wireless LAN.

The NRP base unit accommodates up to 4 sensor heads, and displays all four measurement results at the same time. Alternatively, the sensors can be connected directly to a PC via USB interface.

Applications in manufacturing test also benefit from the instrument's high measurement speed, its ease of use, and remote controllability. The NRP is lightweight and robust, and operates over a wide temperature range. This makes the instrument an excellent choice also for installation, service and maintenance in the field.

 Plug In and Measure with High Accuracy through SMART SENSOR TECHNOLOGY

The accuracy of microwave power measurements depends on the sensor characteristics, and is impacted by signal level, temperature and frequency. For the NRP, Rohde & Schwarz is using an approach it introduced years ago: all calibration data is stored directly in the sensor, which ensures high-precision measurements and minimizes operating errors. This eliminates the need for calibration before the measurement. After plugging in the sensor the measurement can be started immediately. The sensors can perform reliable measurements for an extended period of time and the recommended calibration interval is 2 years.

In the past, microwave power meters required different sensors to cover all applications: thermal, diode as well as peak power sensors. The sensors from the NRP family now make life much easier – in many cases, a single sensor can perform all necessary measurements: average power, burst power and time gating also on signals with high bandwidth and wide dynamic range. This capability is achieved with the innovative SMART SENSOR TECHNOLOGY™, a fused multiple-path architecture:

• 3 signal paths, each fitted with triple diodes
• 6 dB wide overlap ranges, smooth transitions from one path to the other
• Parallel signal processing in the three paths with simultaneous scanning and analysis
• Chopper stabilization of signal paths for recurring signals

S-Parameter and G Corrections – Accounting for the Source Mismatch

Errors in power measurements on RF and microwave signals are often caused by a mismatch of source and sensor. To reduce the mismatch, the complex reflection coefficient G of the source is transmitted to the sensor via the USB data interface. The sensor then corrects the matching error by means of G correction, taking into consideration its own low impedance mismatch. This approach yields measurement results of significantly higher precision.

A similar mismatch problem is encountered where the sensor is connected to the source via a cable or an attenuator for level matching. This applies especially in production facilities. For the NRP, a PC software tool allows the transmission of the complete s-parameter data set of the additional component into the sensor's memory via the USB data interface. This yields a perfectly correct reading and the sensor practically behaves as if it was connected directly to the source.

High Measurement Throughput for Production Test

The NRP is equipped with several new features that help increase measurement throughput over conventional approaches. These include an enhanced auto-filter function, a user definable measurement window, and a high sample rate.

To obtain a noise-reduced display, the measurement signal is filtered via averaging which increases the measurement time. The classic auto-filter function must compromise between measurement time and display noise, but this can lead to an unacceptable noise level. The enhanced auto-filter function now offers a Fixed Noise mode in which the sensor keeps the S/N ratio below a user defined level, as long as the user-defined measurement time is not exceeded. This results in stable measurement results matched to the user’s needs.

Very low-frequency-modulated signals are typically measured using large averaging factors to keep the display stable. In order to shorten the measurement time the NRP uses windowing. In this mode, the measurement time interval is adapted to the signal period. Adjusting the window to the modulation period yields a perfectly stabilized measurement result. If the size of the measurement window is not critical and filtering is not necessary, the NRP excels with 1500 measurements per second (buffered mode, measurement interval 2 x 100 µs).

Signal-Synchronized Measurements

The Diode Power Sensors NRP-Z11, -Z21 can measure the average power not only continuously over the signal, but also synchronized with the signal over definable periods of time. This is useful for measurements on signal bursts and individual timeslots of time division systems as well as power vs. time measurements.

To support signal-synchronized measurements the NRP offers extensive trigger capabilities. The trigger can be derived from the test signal (internal triggering) or from an external signal. The internal trigger is particularly useful for burst measurements. Unwanted power components at the beginning or end of the burst can be excluded from the displayed result with the commands EXCLUDE START and EXCLUDE END.

With an external trigger signal, the NRP can carry out measurements on signals with up to 128 timeslots (26 when controlled by the basic unit). This allows entire frames of GSM/EDGE signals to be analyzed. The number and timing of the timeslots relative to the trigger event is user selectable. On the NRP base unit the trigger input is situated on the rear panel. If the sensor is operated from a PC, triggering via the USB Adapter NRP-Z3 is possible.

For more in-depth signal analysis the PC software toolkit offers the display of a power vs. time template for recurring and non-recurring waveforms. This function relies on internal or external trigger, and requires that the power sensors be connected directly to a PC via USB interface. The number of test intervals (points) can be increased to 1024, and signal details down to a duration of about 10 µs can be resolved.

Power Sensor with USB Interface - Connect Directly to a PC

The sensors of the NRP-Z series are complete miniature power meters, and can be used alone without the NRP display unit. The sensors contain a CPU that controls the sensor, processes the measurement results and operates the interface. All measurement data and settings can be transmitted via an optional USB interface. This concept is being used for the first time in classic microwave power measurement.

Connecting the sensors directly to a PC is the most cost-effective method for high-precision power measurements, especially if a PC is used already for data acquisition and evaluation. This is commonly the case in production environments that include a process controller. Omitting the NRP display unit saves space in the rack and reduces costs. Service technicians will also appreciate this option since the power sensor is only 1.9 x 1.2 x 6.7 inches and can easily be operated from a laptop.

A software toolkit is required to control the NRP power sensors via a PC. This toolkit is supplied as standard with every NRP sensor. It includes a DLL (dynamic link library) for individualized use of the entire sensor functionality under Windows, and the Power Viewer, a virtual power meter with basic measurement functions for the PC workstation. The Power Viewer includes a subset of the functionality of the NRP base unit. The passive USB Adapter NRP-Z4 provides all basic functions. It handles the transmission of settings and measurement data as well as the power supply of the sensor. The active USB Adapter NRP-Z3 for applications requiring external triggering of the power sensor. It also offers a separate power supply.

Universal Display Unit

For applications requiring a basic unit, the NRP offers key advantages. It has a small size, and is lightweight and rugged. It can be fitted with one, two or four measurement inputs (Options NRP-B2 and NRP-B5). GPIB is standard as are trigger input and analog measurement output.

The user interface of the NRP power meter is controlled similarly to a PC via menu bars, menus and dialog boxes. All functions are grouped into only three menu levels, and the operating concept is self-explanatory. The high-resolution graphical display can show as many as four measurement results at the same time. The user can choose whether to display data from up to four different sensors, or from different timeslots of a TDMA signal measured by one sensor. Values obtained by calculation, such as SWR or return loss, can also be displayed.

NRP Display Unit Options:

NRP-B1: Sensor Check Source - The test generator is provided to check the function of the sensor, eg. after overloading or excessive mechanical stress. It generates a low-distortion, highly accurate 50 MHz signal of 1 mW power (0 dBm).

NRP-B2: Second Sensor Input (B) - Provides the 2nd sensor input, located on the front panel of the NRP.

NRP-B5: 3rd and 4 th Sensor Input (C, D) - The NRP unit can be equipped with 4 measurement inputs to handle 4 sensors simultaneously. To make the results from all 4 sensors visible 4 different display windows can be opened on the NRP unit. All the results from the four different sensors can be transmitted via the remote interface to a PC in parallel.

NRP-B6: Rear-panel Sensor Input A & B - Using the NRP in a test rack, it is useful to change the 1st and 2nd sensor input from the front side to the rear panel. (not to be fitted with option R&S NRP-B5).