Measure OIP3 of Device Under Test

Use the OIP3 Testbench block to measure the output third order intercept (OIP3) of a device under test (DUT).

Connect the blocks as shown in the model.

Set the parameters for DUT and the testbench.

Amplifier block:

• Available power gain — 10 dB

• Intercept points convention – Output

• IP3 – 32 dBm

Mixer block:

• Available power gain — 5 dB

• Local oscillator frequency — 2.0 GHz

• Add Image Reject filter — on

• Intercept points convention — Output

• IP3 — 35 dBm

• Filter type — Highpass

• Implementation — Constant per carrier

• Passband edge frequency — 2.05 GHz

OIP3 Testbench block:

• Input frequency (Hz) — 2.1e9

• Output frequency (Hz) — 0.1e9

• Simulate noise (both stimulus and DUT internal) — off

Run the model. You will see that the Display block shows an OIP3 value of 32.87 dBm. This value can be verified analytically using the IIP3 equation provided in [1].

OIP3 of the DUT = IIP3 + Gain = – 10*log10(1/10^((22)/10) + 10^(10/10)/10^((30)/10)) + 15 = 32.8756 dBm

where,

IIP3 of the amplifier in linear scale =10^((32-10)/10), as IIP3 = OIP3 – Gain ; IIP3 = 32 dBm – 10 dB = 22 dBm

IIP3 of the mixer in linear scale = 10^((35-5)/10), as IIP3 = OIP3 – Gain ; IIP3 = 35 dBm – 5 dB = 30 dBm

Available power gain of the amplifier = 10^(10/10)

References

[1] Razavi, Behzad. “Basic Concepts “ in RF Microelectronics, 2nd edition, Prentice Hall, 2012.