The National Instruments 781214-01 RF Power Sensor, also referred to as the USB-5681, is engineered for precision RF power measurements, delivering accuracy from 10 MHz to 18 GHz. This sensor excels in applications dealing with continuous wave, multitone, and digitally modulated signals, offering reliable average power readings within a dynamic range of 60 dB and input power capabilities spanning from -40 dBm to +20 dBm. Its innovative dual-path architecture ensures precise RMS measurements across the full frequency and dynamic range, while advanced features, including auto averaging and repeat averaging, enhance its performance. With a typical sample rate of 140 kS/s, the sensor captures high-resolution data, and its configurable aperture time of 0.01 ms to 300 ms provides adaptable timing for various measurement scenarios. The duty cycle correction feature is particularly beneficial for pulse-modulated signal analysis, ensuring accurate power assessments for both continuous and pulsed signals.

The NI 781214-01 also incorporates robust triggering options, supporting both internal and external triggers. Internal trigger levels range from -20 dBm to +20 dBm with a typical accuracy of ± 0.5 dB, while external triggers are compatible with TTL/CMOS signals. This flexibility facilitates various measurement initiation methods, and features such as trigger delay and noise immunity guarantee stable and reliable measurements even in challenging environments. Its time slot and scope measurement modes enable detailed analysis of captured signals, accommodating up to 1,024 data points or 128 time slots. The device's onboard calibration and correction data eliminate the need for frequent external recalibration, promoting rapid setup and dependable measurements. With a linearity uncertainty of less than 3% and temperature compensation effective across a broad operating range (0 °C to 50 °C) with a compensation rate of less than 1.4%, the sensor maintains accuracy under varying conditions.

Compact and lightweight, the 781214-01 measures 25 mm x 45 mm x 110 mm and weighs only 230 grams, making it suitable for various applications, including those at altitudes up to 4,600 meters. It is designed to meet MIL-PRF-28800F standards for shock and vibration resistance, ensuring reliability in demanding industrial environments.