Making Basic Measurements Using Spectrum Analyzer Mode

Identifying Distortion Products Using the RF Attenuator and Traces

Third-Order Intermodulation Distortion

Two-tone, third-order inter-modulation distortion is a common problem in communication systems. When two signals are present in a system, they can mix with the second harmonics generated and create third-order inter-modulation distortion products, which are located close to the original signals. These distortion products are generated by system components such as amplifiers and mixers.

Example: Test a device for third-order inter-modulation. This example uses two sources, one set to 300 MHz and the other to approximately 301 MHz. (Other source frequencies may be substituted, but try to maintain a frequency separation of approximately 1 MHz.)

1. Connect the equipment as shown in Figure 4-23.

Figure 4-23. Third-Order Intermodulation Equipment Setup

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