User rate mode

The user rate setting allows you to directly control the digitizer’s sample rate. In this mode you select the digitizer sample rate to be used. The actual sample rate selected will be the highest rate that is less than or equal to the “user sample rate” setting. By controlling the digitizer’s sample rate you can directly inﬂuence the update rate of the VSA. This is because sample rate directly affects the num- ber of points the digitizer must transfer to the PC. Certain measurements can be made signiﬁcantly faster by limiting the digitizer sample rate due to reduced data transfer requirements.

There are two types of signal aliasing to be concerned with when using the 89600 VSA application with an Agilent Acqiris digitizer. The ﬁrst is aliasing of unwanted out-of-band signals into the measurement span. This will not be a problem with the majority of clean, single-signal devices. However, devices with multiple or spurious signals could have this type of aliasing. Section 6 describes how to perform a check to determine if there are any unwanted signals present that can alias down into the measurement span. A second type of aliasing hap- pens when the sample rate causes the in-band signal to fold over on itself. This in-band (or self-) aliasing is avoided in full rate mode by automatically selecting the highest sample rate. However, in user rate mode in-band aliasing may be a problem. To avoid in-band aliasing you must select a suitable sample rate based on your measurement center frequency and span.

To avoid in-band aliasing the digitizer sample rate (FS) must be selected so that the analysis span falls within conﬁned regions. Staying within these regions prevents the analysis span from being positioned too close to FS/2. When FS is selected so that the span is conﬁned to be within a single gray box (see diagrams below), in-band aliasing is avoided. See the following table for the equations that describe these in-band alias-free regions.

The primary use of user rate mode is to increase maximum waveform length that can be acquired or to increase the update rate. In all cases, user rate measure- ments must be been carefully engineered to avoid unwanted alias signals.

Baseband:

DC	Fs/2.56 Fs/2

Zoom:

n * Fs

(n + 1/2) * Fs

(n + 1)Fs

Figure 2. Avoiding in-band aliasing by selecting FS within a conﬁned span

NOTE: User Rate is the only available mode in HF operation. The VSA does not attempt to avoid alias exposure regions when in User Rate mode.

89600 specifications

Agilent Technologies, a leading player in the test and measurement sector, has developed the 89600 VSA (Vector Signal Analysis) software, a powerful tool designed for a wide variety of signal analysis applications. This software is crucial for engineers and researchers developing and testing wireless communication systems, radar technologies, and other complex signal environments.

One of the main features of the Agilent 89600 is its capability to analyze both analog and digital signals with high precision and flexibility. It supports a broad range of modulation formats used in modern communication systems, including LTE, Wi-Fi, GSM, and many others. This extensive modulation support enables users to test their designs against industry standards and protocols, ensuring compliance and operational integrity.

The 89600 VSA software excels in its real-time analysis capabilities, which is critical for evaluating transient signal behavior and understanding time-varying signals. With its advanced algorithms and fast processing capabilities, users can perform real-time demodulation of complex signals, which is vital for debugging and optimizing communication systems. The software also supports offline analysis, allowing engineers to capture and analyze signals at their convenience.

Another standout characteristic of the 89600 software is its intuitive user interface, which streamlines the setup process and enhances user experience. The drag-and-drop functionality allows for easy configuration of measurement setups, while comprehensive visualization tools provide deep insights into the signal characteristics. Users can visualize modulation quality, spectral components, and error vectors through various graphical representations.

The software integrates seamlessly with Agilent's hardware spectrum analyzers and signal generators, offering a holistic solution for signal generation and analysis. It also supports a wide range of signal inputs, from hardware-based vector signal generators to recorded data files.

Moreover, the flexibility of the Agilent 89600 is enhanced through its modular architecture, which allows users to easily add new measurement capabilities via optional software packages. This adaptability ensures that the tool stays relevant as communication technologies evolve.

In summary, Agilent Technologies' 89600 VSA software combines advanced signal analysis capabilities with user-friendly features to provide a comprehensive solution for communication engineers. Its ability to handle multiple modulation formats, real-time analysis, and robust visualization tools makes it an essential resource for anyone involved in the development and testing of signal-based technologies.