9 Two-Tone Waveform Generator

In the following sections, this chapter describes the two- tone mode, which is available only in E8267D PSG vector signal generators with Option 601 or 602:

•“Overview” on page 195

•“Creating, Viewing, and Modifying Two- Tone Waveforms” on page 195 See also: “Arbitrary (ARB) Waveform File Headers” on page 72

Overview

The two- tone mode builds a waveform that has two equal- powered CW signals, or tones. The default waveform has two tones that are symmetrically spaced from the center carrier frequency, and have user- defined amplitude, carrier frequency, and frequency separation settings. The user can also align the tones left or right, relative to the carrier frequency.

The two- tone waveform generator is designed for testing the intermodulation distortion characteristics of non- linear devices, such as mixers or amplifiers. Intermodulation distortion (IMD) occurs when non- linear devices with multiple input frequencies interfere with adjacent channels or cause unwanted outputs at other frequencies. The two- tone waveform generator supplies a signal whose IMD products can be measured using a spectrum analyzer and used as a reference when measuring the IMD generated by a device- under- test.

Two- tone waveforms are created using the internal I/Q baseband generator and stored in ARB memory for playback. Although the two- tone mode generates a high- quality waveform, a small amount of IMD occurs. In addition to IMD, a small amount of carrier feedthrough and feedthrough- related IMD may be present when the spacing between the tones is centered on the carrier frequency. To minimize carrier feedthrough for a two- tone signal, you must manually adjust the I and Q offsets while observing the center carrier frequency with a spectrum analyzer. For measurements that require the absence of IMD and carrier feedthrough, you can create distortion- free multitone signals using Agilent Technologies’ Signal Studio software Option 408.

NOTE For more information about two- tone waveform characteristics and the E8257D/67D PSG Vector Signal Generator two- tone format, download Application Note 1410 from our website by going to http://www.agilent.com and searching for “AN 1410” in Test & Measurement.

Creating, Viewing, and Modifying Two-Tone Waveforms

This section describes how to set up, generate, and modify a two- tone waveform while viewing it with a spectrum analyzer. Although you can view a generated two- tone signal using any spectrum analyzer that has sufficient frequency range, an Agilent Technologies PSA Series High- Performance Spectrum Analyzer was used for this demonstration. Before generating your signal, connect the spectrum analyzer to the signal generator as shown in Figure 9- 1.

Chapter 9

195

Page 208 Page 210
Page 209
Image 209
Agilent Technologies E8257D PSG manual Two-Tone Waveform Generator, Creating, Viewing, and Modifying Two-Tone Waveforms
Page 208 Page 210

E8267D PSG, E8257D PSG specifications

Agilent Technologies, a recognized leader in electronic measurement and communications solutions, offers a comprehensive range of signal generators, including the E8257D PSG (Pulsed Signal Generator) and E8267D PSG. These instruments are engineered to meet the demanding requirements of wireless communication, aerospace, defense, and various research applications.

The E8257D PSG is known for its versatility and reliability. It operates within a frequency range of 250 kHz to 40 GHz, making it suitable for a wide array of applications, from signal generation to vector modulation. With an output power capability of up to +30 dBm, it delivers high-quality signals with exceptional precision. Its low phase noise performance is especially critical for applications such as radar and communication system testing, where signal integrity is paramount.

One of the standout features of the E8257D is its advanced modulation capabilities, including analog and digital modulation schemes. This flexibility allows engineers to simulate real-world communications environments accurately. The PSG also features a built-in arbitrary waveform generator that enables users to create complex waveforms tailored to specific testing needs, providing a significant advantage in research and development.

On the other hand, the Agilent E8267D PSG is designed to cater to the needs of users requiring a combined signal generation and analysis solution. With the capability to generate signals from 250 kHz to 67 GHz, the E8267D is ideal for millimeter-wave applications, as well as testing next-generation wireless technologies.

This model includes features such as enhanced phase noise performance and faster switching speed, which are crucial for signal integrity in sophisticated networks. The instrument's intuitive user interface and powerful software integration facilitate effortless operation and automation, thereby improving workflow efficiency.

Both the E8257D and E8267D PSG instruments incorporate cutting-edge technologies such as low-noise microwave and RF components, as well as digital signal processing capabilities. They provide users with enhanced accuracy and reliability in their measurements.

In summary, Agilent Technologies' E8257D and E8267D PSG signal generators represent the pinnacle of precision in signal generation technology. With their extensive feature sets, advanced modulation capabilities, and robust performance specifications, these instruments are invaluable tools for engineers and researchers working across various high-tech industries.
Top Page Image Contents