Intermodulation Distortion Calculator

Calculate 2nd and 3rd order intermodulation products from two-tone input signals.

What is Intermodulation Distortion?

When two guitar notes play together, you sometimes hear phantom notes that nobody played — those are intermodulation products. RF amplifiers and mixers do the same thing: feed them two signals and they produce unwanted extra frequencies that weren't there before.

Why it matters: Cell towers near each other can create phantom signals that interfere with calls. Engineers use OIP3 and spur charts to design receivers that reject these unwanted products before they cause problems.

Input Tones
Two CW tones applied simultaneously.
MHz

First signal frequency — like the first guitar note

MHz

Second signal frequency — should be close to f1 to create nearby phantom products

dBm

How strong each signal is at the input. 0 dBm = 1 milliwatt

Device Parameters
Nonlinearity intercept point.
dBm

How much distortion your device creates — higher is better. Typical amplifier: 20–40 dBm.

dBm

The quietest signal the system can hear. Used to calculate how cleanly it can distinguish signals.

Intermodulation Products
All 2nd and 3rd order mixing products with their frequencies and power levels.

IM3 Level

-90.0 dBm

IM2 Level

-80.0 dBm

SFDR

86.7 dB

IIP3 (0 dB gain)

30.0 dBm

OrderProductFrequencyLevel
IM2f1 + f2201.000 MHz-80.0 dBm
IM2|f1 − f2|1.000 MHz-80.0 dBm
IM22·f1200.000 MHz-80.0 dBm
IM22·f2202.000 MHz-80.0 dBm
IM32·f1 − f299.000 MHz-90.0 dBm
IM32·f2 − f1102.000 MHz-90.0 dBm
IM32·f1 + f2301.000 MHz-90.0 dBm
IM32·f2 + f1302.000 MHz-90.0 dBm

The 3rd order products at 2f1−f2 and 2f2−f1 fall closest to the fundamental tones and are the most problematic in receiver design.