Keysight N432A – Thermistor Power Meter

• Single-channel, average RF power meter
• Operates with the Keysight 8478B and 478A thermistor mounts
• Replacement for Keysight’s legacy 432A analog thermistor power meter
• N432A-and-thermistor-mount pair is ideal for applications that require high measurement accuracy, particularly in metrology and calibration laboratory environments

The N432A is a single-channel, average RF power measurement meter that supports thermistor sensors. The N432A has the capability to measure and display average power, RF bridge voltages (VRF0 and VRF1), compensation bridge voltages (VCOMP0 and VCOMP1), V0, and V1. It is also provided with a set of features such as zeroing and a built-in self-test.

Developed using LXI technology, the N432A is an LXI Class-C compliant instrument.

The N432A basic configuration consists of two key sections: bridge and meter logic. When a compatible thermistor sensor is connected to the N432A, the RF and compensation bridge circuits are formed in the bridge section. VRF, which is the voltage at the top of the RF bridge, is responsive to both input RF power and ambient temperature changes. On the other hand, VCOMP, which is the voltage at the top of the compensation bridge, is responsive only to ambient temperature changes. The VRF and VCOMP values are used in calculating the RF power. Meanwhile, the meter logic section processes VRF and VCOMP to produce a meter current proportional to RF power.

In general, the N432A is an easy-to-use instrument, especially with the availability of an integrated Web browser that provides a convenient way to view and modify the instrument network configuration. Besides the LAN interface, the N432A also supports industry standard GPIB and USB interfaces for measurement automation.

High accuracy – no thermoelectric error

The high accuracy ± (0.1% of reading + 0.5 μW) over a wide temperature range featured in the legacy 432A power meter is also included in the N432A, making it excellent for 1 mW transfer calibration (with 478A-H75/H76). Accuracy can be maintained on even the most sensitive range as the error due to thermoelectric effect is reduced to a negligible level.