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Agilent Technologies Third-Order Intermodulation Distortion , Identifying TOI Distortion Example:

Models: E7401A E7402A E7403A E7404A E7405A

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Chapter 1 45

Making Basic Measurements

Identifying Distortion Products

Figure 1-37 No Harmonic Distortion

Third-Order Intermodulation Distortion

Two-tone, third-order intermodulation distortion is a common test in

communication systems. When two signals are present in a non-linear

system, they can interact and creat e th ir d-order intermodulation

distortion products that are located close to the original signals. These

distortion products are generated by system components such as

amplifiers and mixers.

Identifying TOI Distortion Example:

Test a device for third-order intermodulation. This example uses two

sources, one set to 300MHz and the other to approximately 301 MHz.

(Other source frequencies may be substituted, but try to maintain a

frequency separation of approximately 1MHz.)

1. Connect the equipment as shown in Figure 1-38. This combination of

signal generators, low pass filters, and di rectional coupler (used as a

combiner) results in a two -tone source with very low

intermodulation distortion. Although the distortion from this setup

may be better than the specified performance of the analyzer, it is

useful for determining the TOI performance of the source/analyzer

combination. After the performance of the source/analyzer

combination has been verified, the device-under-test (DUT) (for

example, an amplifier) would be inserted between the directional

coupler output and the analyzer input and another measurement

would be made.

Contents

Main Signal Analysis Measurement Guide Agilent Technologies EMC Series Analyzers Notice Safety Information Warrant y LIMITATION OF WARRANTY EXCLUSIVE REMEDIES Where to Find the Latest Informa tion Page Contents Page What is in This Chapter Test Equ ipm ent Comparing Signals Signal Comparison Example 1: Page Signal Comparison Example 2: Page Resolving Signals of Equal Amplitude Resolving Signals Example: Page Page Resolving Small Signals Hidden by Large Signals Resolving Signals Example: Page Page Making Better Frequency Measurements Better Frequency Measurement Example: Page Decreasing the Frequency Span Around the Signal Decreasing the Frequency Span Example: Page Page Tracking Drifting Signals Tracking Signal Drift Example 1: Page Page Tracking Signal Drift Example 2: Page Page Page Measuring Low Level Signals Measuring Low Level Signals Example 1: Page Measuring Low Level Signals Example 2: Measuring Low Level Signals Example 3: Page Measuring Low Level Signals Example 4: Page Page Identifying Distortion Products Distortion from the Analyzer Identifying Analyzer Generated Distortion Example: Page Page Third-Order Intermodulation Distortion Identifying TOI Distortion Example: Page Page Page Measuring Signal-to-Noise Signal-to-Noise Measurement Example: S/N 70 dB/Hz10 30 kHz()log+ 25.23 dB30 kHz()== Making Noise Measurements Noise Measurement Example 1: Page Page Page Page Noise Measurement Example 2: Noise Measurement Example 3: Page Page Demodulating AM Signals (Using the Analyzer As a Fixed Tuned Receiver) Demodulating an AM Signal Example 1: Page Page Page Page Page Demodulating FM Signals Demodulating a FM Signal Example: Page Page Page Page Whats in This Chapter Required Test Equipment Making Stimulus Response Measu rements What Are Stimulus Response Measurements? Using An Analyzer With A Tracking Generator Stepping Through a Transmission Measurement Page Page Page Page Tracking Generator Unleveled Condition Measuring Device Bandwidth Page Page Measuring Stop Band Attenuation Using Log Sweep Page Page Page Page Making a Reflection Calibration Measurement Example: Reflection Calibration Measuring the Return Loss Chapter 2 87 VSWR 110 Making Complex Measurements Making a Reflection Calibration Measurement -----------------------= Table 2-1 Power to VSWR Conversion + 110 Demodulating and Listening to an AM Signal Demodulating and Listening to an AM Signal Example 1: Demodulating and Listening to an AM Signal Example 2: