Dual Sourced Low Tier Commercial Sensor Supply Exposure
Dual-sourcing low-tier commercial sensors introduces baseline offset drift, thermal hysteresis, and ASIC filtering divergence that increase total landed product cost.
1/f Noise Floor
Spectrum Baseline
Low frequency spectral power density represents the intrinsic limit of a sensor’s resolution at near-static conditions. Within this region, the 1/f noise floor describes a stochastic signal power that increases as frequency decreases. It originates from material impurities and charge trapping at semiconductor interfaces.
Standard specifications typically define this value at 1 Hz or 0.1 Hz to allow for a baseline comparison between different high precision amplifiers or inertial sensors.
Frequency Dependency
Electronic components exhibit a characteristic rise in amplitude known as flicker noise that dominates the signal at the lower end of the bandwidth. Because the 1/f noise floor follows an inverse relationship with frequency, it differs from the flat white noise seen at higher spectral ranges. The magnitude of this effect determines the long term stability of a measurement system.
Designers identify the point where this slope meets the thermal noise as the 1/f corner.
Corner Frequency
The transition from frequency dependent fluctuations to a constant power spectral density occurs at a specific intersection point. Selection of a device with a lower 1/f noise floor ensures that the signal remains clear of low frequency disturbances for a wider operational range.
Measurement Threshold
Precision instrumentation requires active techniques such as chopping or auto zeroing to bypass the limitation. This circuitry periodically swaps the input terminals to cancel out the low frequency components. By modulating the signal to a higher frequency, the impact of the noise floor is effectively removed from the DC measurement range.
These systems are necessary for weight scales and temperature monitors that operate over long intervals.