Agilent Technologies E4406A manual Making the Spectrum Frequency Domain Measurement, Purpose

NOTE

Making Measurements

Making the Spectrum (Frequency Domain) Measurement

Making the Spectrum (Frequency Domain) Measurement

Purpose

The spectrum measurement provides spectrum analysis capability for the instrument. The control of the measurement was designed to be familiar to those who are accustomed to using swept spectrum analyzers.

This measurement is FFT (Fast Fourier Transform) based. The FFT-specific parameters are located in the Advanced menu. Also available under basic mode spectrum measurements is an

I/Q window, which shows the I and Q signal waveforms in parameters of voltage versus time. The advantage of having an I/Q view available while in the spectrum measurement is that it allows you to view complex components of the same signal without changing settings or measurements.

Measurement Method

The measurement uses digital signal processing to sample the input signal and convert it to the frequency domain. With the instrument tuned to a fixed center frequency, samples are digitized at a high rate, converted to I and Q components with DSP hardware, and then converted to the frequency domain with FFT software.

This measurement is available for both the RF input and baseband I/Q inputs. For details on Baseband I/Q operation see “Using Baseband I/Q Inputs (Option B7C)” on page 151.

Making the Measurement

The factory default parameters provide a good starting point.You will likely want to change some of the settings. Press Meas Setup, More (1 of 2), Restore Meas Defaults at any time to return all parameters for the current measurement to their default settings.

Press Measure, Spectrum (Freq Domain) to immediately make a spectrum measurement.

To change any of the measurement parameters from the factory default values, refer to the “Changing the Measurement Setup” section for this measurement.

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