Spatial Thermal Gradient Mapping Micro-Machined Accelerometer Arrays
Spatial thermal gradient mapping in micro-machined accelerometer arrays decouples linear motion from external board heat using differential thermopile matrices.
Power Supply Rejection Ratio
Suppression Factor
Logarithmic ratios quantify the ability of an electronic circuit to suppress noise on the power supply line from appearing at the output. The power supply rejection ratio measures the change in output voltage relative to a change in the supply voltage across a range of frequencies. A high value indicates that the sensor output is independent of fluctuations in the battery or mains power.
This metric is expressed in decibels.
Frequency Dependency
Most circuits reject low frequency noise more effectively than high frequency ripples. The power supply rejection ratio typically drops as the frequency of the power supply interference increases. Engineers must consider the switching frequency of the power regulators when evaluating this parameter.
Circuit Design
Differential amplifiers and voltage regulators are designed to maximize this rejection. A high power supply rejection ratio prevents the 50 or 60 hertz hum from interfering with low level sensor signals. Filtering capacitors are added to the supply lines to assist the internal circuitry in noise suppression.
Testing Requirement
Calibration labs inject a small AC signal onto the DC supply line to measure the resulting output variation. Knowing the power supply rejection ratio allows the system integrator to specify the maximum allowable noise on the power distribution network. This ensures that the instrument maintains its rated accuracy in a noisy industrial setting.