How to Characterize Amplifier Intermodulation Distortion and IP3

Get Quote
Expert Analog Signal Generator
+ Expert Analog Signal Generator
Expert Analog Signal Generator
+ Expert Analog Signal Generator

IP3 Characterization Solution

Characterizing amplifier intermodulation distortion and third-order intercept point (IP3) requires two continuous-wave RF signals with closely spaced frequencies, controlled output levels, and sufficient spectral purity to avoid introducing unwanted distortion into the measurement. The two signals are combined and applied simultaneously to the amplifier input, producing the desired fundamental output tones along with intermodulation products generated by amplifier nonlinearities. A signal analyzer measures the fundamental tones and third-order intermodulation products, typically located at frequencies 2f1 − f2 and 2f2 − f1. The test setup requires careful control of source power, tone spacing, combining losses, and analyzer settings so the measured intermodulation distortion represents the amplifier response rather than distortion generated by the test equipment.

To determine IP3, engineers repeat the two-tone measurement while varying the amplifier input power and recording the resulting fundamental and third-order intermodulation levels. The fundamental output tones increase approximately linearly with input power in the amplifier's linear operating region, while third-order intermodulation products increase at a higher rate. These measured levels can be used to extrapolate the fundamental and third-order responses to their theoretical intersection, establishing the third-order intercept point. Input-referred IP3 or output-referred IP3 can then be calculated according to the measurement reference plane. Repeating the measurement across frequency, tone spacing, or amplifier operating conditions provides intermodulation distortion and IP3 characterization across the required RF operating range.

IP3 Characterization Solution

Characterizing amplifier intermodulation distortion and third-order intercept point (IP3) requires two closely spaced continuous-wave RF tones with independently controlled frequency and power, combined into a single stimulus at the amplifier input. Keysight analog signal generators provide the RF sources needed to establish the two-tone stimulus with controlled output levels and spectrally clean signals. A signal analyzer measures the amplifier’s fundamental output tones and third-order intermodulation products while the input power is varied. Comparing the measured fundamental and intermodulation levels enables calculation of input- or output-referred IP3 and characterization of amplifier linearity. Engineers can adjust carrier frequency, tone spacing, and power levels to characterize intermodulation distortion across the amplifier’s operating range. This solution provides the controlled RF stimulus and signal analysis required for repeatable intermodulation distortion measurements, IP3 characterization, RF amplifier characterization, and production verification.
Get Quote

See Block Diagram of IP3 Characterization Solution

How to Characterize Amplifier Intermodulation Distortion and IP3 Block Diagram

Explore Products in Our IP3 Characterization Solution

Discover Resources and Insights

Additional Resources for Characterizing Amplifier Intermodulation Distortion and IP3

Related Use Cases

How to Perform IoT RF Receiver Testing

Validate IoT receiver sensitivity and robustness with controlled RF signals from the N5166B.

Learn More

How to Create Custom I/Q Waveforms

Create and download custom baseband I/Q waveforms with the N5166B for flexible RF signal generation and receiver test.

Learn More

How to Generate Interference Signals for Receiver Testing

Use the Keysight N5166B Essential Vector Signal Generator to generate controlled RF interference signals for receiver robustness and coexistence testing.

Learn More

contact us logo

Get in Touch with One of Our Experts

Need help finding the right solution for you?

Contact Us