Spurious Free Dynamic Range Converter

This tool calculates the Spurious Free Dynamic Range (SFDR) of an RF receiver using the Third Order Intercept Point (IIP3) and Minimum Detectable Signal (MDS). It helps determine the usable dynamic range before distortion or noise limits signal quality.

Formula

SFDR = (2/3) * (IIP3 – MDS)

If IIP3 is given in watts, convert it to dBm: IIP3_dBm = 10 * log10(IIP3 * 1000)

Formula Explanation

• IIP3 is the input power level where third-order distortion equals the desired signal power.
• MDS represents the lowest signal that the receiver can detect above noise.
• SFDR expresses how far apart these two limits are, indicating system linearity.

Example

Input: IIP3 = 10 dBm, MDS = -120 dBm

Result: SFDR = (2/3) × (10 – (-120)) = 86.67 dB

Who uses it

Helpful for RF designers and communication engineers evaluating receiver performance and distortion levels.