RF Measurements

P1dB / IP3 / IM3 / SFDR

Analyze two-tone third-order distortion, compression headroom and dynamic range.

Inputs

Results update as you enter values. Inputs stay in this browser session only.

Input power per tone

dBm

Small-signal gain

Input IP3

dBm

Output noise floor in measured bandwidth

dBm

Input P1dB (optional)

dBm

Results

Output carrier per tone (linear estimate)

-10 dBm

OIP3

20 dBm

IM3 output per product

-70 dBm

Carrier-to-IM3 separation

60 dBc

Two-tone SFDR

80 dB

Output P1dB

9 dBm

Input headroom to P1dB

20 dB

How it works

OIP3 = IIP3 + G; PIM3,out = 3Pin + G − 2IIP3; SFDR = ⅔(OIP3 − Nout).

Engineering assumptions

Powers are per tone. Noise floor is output referred in a specified measurement bandwidth. The small-signal IM3 extrapolation requires input power below IIP3 and P1dB. P1dB is independent of IP3.

Related calculators

VSWR / Return Loss / Reflection Coefficient