Agilent Technologies E7401A, E7402A, E7403A, E7404A, E7405A Making Stimulus Response Measu rements

Chapter 2 71

Making Complex Measurements

Making Stimulus Response Measurements

Making Stimulus Response Measu rements

What Are Stimulus Response Measurements?

Stimulus response measurements require a source to stimulate a device

under test (DUT), a receiver to analyze the frequency response

characteristics of the DUT, and, for return loss measurements, a

directional coupler or bridg e. Characterization of a DUT can be made in

terms of its transmission or reflection parameters. Examples of

transmission measurements include flatness and rejection. Return loss

is an example of a reflection measurement.

A spectrum analyzer combined with a tracking generator forms a

stimulus response measurement system. With the tracking generator

as the swept source and the analyzer as the receiver, operation is the

same as a single channel scalar network analyzer. The tracking

generator output frequency must be made to precisely track the

analyzer input frequency for good narrow band operation. A narrow

band system has a wide dynamic measurement range. This wide

dynamic range will be illustrat e d in t h e fo llowing example.

Using An Analyzer With A Tracking Generator

There are three basic steps in performing a stimulus response

measurement, whether it is a transmission or a reflection

measurement. The steps are to set all the analyzer settings, normalize,

and measure.

The procedure below describes how to use a built in tracking generator

system to measure the rejection of a band pass filter, a type of

transmission measurement. Illustrated in this example are functions in

the tracking generator menu such as adjusting the tracking generator

output power. Normalization functions located in the trace menu are

also used. Making a reflection measurement is similar and is covered in

“Making a Reflection Calibr at io n M e as urement” on page 84.

Stepping Through a Transmission Measurement

1. To measure the rejection of a band pass filter, c onnect the equipment

as shown in Figure 2-1. This example uses a 20 0 MHz bandpass

filter as the DUT.

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: