Carrier Frequency vs DC Excitation: Why HBK Stands Out in Strain Measurement

In precision measurement, accuracy isn’t just important - it’s everything.

This is especially true when working with strain gauge (SG) based transducers, where environmental factors like temperature fluctuations and electrical noise can distort critical readings.

HBK have a range of data acquisition platforms that leverage patented 3-wire and 4-wire technologies alongside Carrier Frequency(CF) Excitation to set a new benchmark in measurement reliability.

Problems with DC Excitation

Traditional DC excitation applies a constant voltage to the Wheatstone bridge. This has two major drawbacks:

• Noise vulnerability: DC systems easily pick up low-frequency electrical noise (e.g., mains hum at 50/60 Hz).
• Temperature drift: Temperature changes can create parasitic thermoelectric voltages in the wires, producing “fake” strain signals.

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The HBK Carrier Frequency Advantage

Carrier Frequency (CF) Excitation replaces constant DC voltage with a high-frequency AC signal (e.g., 225 Hz, 600 Hz, 4.8 kHz).This change unlocks several benefits:

• Exceptional Noise Immunity: The higher frequency shifts the signal away from common noise sources, resulting in dramatically cleaner data.
• Outstanding Temperature Stability: Thermoelectric voltages are ignored during demodulation, reducing zero drift.
• Patented 3 & 4-Wire Compensation: Minimises errors from lead wire resistance changes, even over long cable runs.

Why Does It Matter?

Where precision is critical in electrically noisy or temperature variable environments, such as industrial, weighing, aerospace and even structural health monitoring, then the higher accuracy and stability offered by CF excitation is a major consideration.

For engineers, researchers, and technicians, reliable measurements means less time filtering bad data, and higher confidence in test results. Regardless of environmental conditions, Carrier Frequency excitation delivers true data assurance.

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If you’re still relying on DC excitation for your strain measurements, it may be time to switch. With HBK Carrier Frequency (CF) excitation, you get precision without compromise.

Talk with NVMS today about your testing requirements and ensure your data collection system is performing to your high standards. Contact us here.