Agilent Technologies 89600 manuale d’uso

Agilent Acqiris Broadband High-Speed Digitizers Using 89600 V ector Signal Analyzer Software Application Note V ector signal analysis using Agilent Acqiris broadband digitizers.[...]

2 1 Overview 3 1.1 89600 VSA software 4 1.2 Required software revisions 4 2 Install 89600 VSA Software 5 3 Hardware Confi guration 6 3.1 I/O between computer and digitizer 6 3.2 Anti-alias fi lters and alias exposure-free mode 7 4 Operation 8 4.1 Basic operation 8 4.2 Sampling modes: full rate and user rate 8 4.3 Differences from 89600 VSA operat[...]

3 3 This product note describes the characteristics, setup, and operation of a broadband vector signal analyzer (VSA) comprised of an Agilent Acqiris U1066A (DC440, DC438) or U1065A (DC282, DC252, DC222) high-speed digitizer and the 89600 vector signal analyzer software. By taking advantage of the layered architecture and extensive digital signal p[...]

4 1.1 89600 VSA software The 89600 vector signal analyzer software is the heart of the broadband VSA. This software provides fl exible tools for analyzing and demodulating even the most advanced digital modu- lations, including those not defi ned by an established standard. The VSA makes measurements on signals in the time and frequency domains u[...]

5 5 2 Install 89600 VSA Software The 89600 VSA software must be installed on a computer . Installation for standard operation Insert the Agilent T echnologies 89600 Series Software CD-ROM in your standard PC and follow the instructions in the installation wizard. When the Installation Manager window opens, click Install 89600 Series Software . In t[...]

6 3 Hardware Confi guration Connect the digitizer to the computer as shown in Figure 1a or 1b. There are two options for the connection, by remote computer or by embedded computer . 3.1 I/O between computer and digitizer Operation of the 89600 Series software on an embedded Compact PCI computer is similar to operation on a standard PC. The instruc[...]

3.2 Anti-alias fi lters and alias exposure-free mode The broadband VSA can be confi gured to be essentially alias-free by using the full rate sampling mode and installing an external lowpass fi lter on the digitizer input. Use BNC-f to SMA -m and SMA -f to BNC-m adapters to connect the fi lter’ s SMA connectors to the digitizer in case the di[...]

4 Operation 4.1 Basic operation Operation of the broadband VSA is substantially the same as that of the 89600 VSA. See the following sections for some differences or special confi gurations. There is an online T utorial and Getting Started Guide under the Help/Roadmap toolbar in the 89600 software. 4.2 Sampling modes: full rate and user rate Full [...]

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 in[...]

This table summarizes the difference in approach to alias protection between the various sample modes: Another concern in user rate mode is that you may see unwanted amplitude variability in two channel measurements. This can occur if any part of the mea- surement frequency span falls within the regions defi ned by: (2*n+1) x F S /2 ± 0.1 x F S w[...]

11 The operating region curves for the broadband VSAs are different from those of standard VSAs because the Main Time Length may be limited for some sample rate, center frequency , and span combinations. The differences are due to three hardware characteristics of the ultra-wideband ADCs in the Agilent Acqiris digitizers: • A much higher sampling[...]

12 Figure 3. The user-settable parameter , frequency points, begins to determine the boundaries of the time record length and frequency span operating region 5.2 Operating region curves for Agilent Acqiris digitizers Several interrelated characteristics of both the Acqiris digitizers and the 89600 VSA software combine to form a region within which [...]

13 In addition to the time record length limits, there are limits to the allowable range of spans. These are represented as vertical lines on the operating region graphs (Figure 4). The upper span limit is set by the digitizer’ s sample rate. For the highest sample rate supported by the digitizer this boundary may be further limited by the analog[...]

14 Figure 5. The digitizer’ s available memory also constrains the operating region Figure 4. The allowable range of spans, which may differ by model, further bound the operating region of the digitizer 1.E-08 1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08 1.E+09 1.E+10 1.E+11 Span [...]

15 In full rate sample mode with the use of appropriate lowpass fi ltering (T able 3) signal aliasing is completely avoided. In this case the “Operating Region” is renamed “ Alias Exposure Free Zone” to indicate this special condition. NOTE: Does not apply to HF operation. Although the operating regions for all digitizer models are similar[...]

16 5.3 Recording limits for Acqiris digitizers The 89600 VSA software allows the acquisition of long records to be captured. Analysis is done as a post-processing operation. This feature is called Recording. Recordings can be much longer than time records in live measurements. Prior to taking a recording, live test measurements of Main Time length [...]

17 As mentioned above, the user rate sampling modes increase the maximum Main Time length at the expense of possible aliasing of out-of-band signals into the frequency span of the measurement. The spectrum ranges subject to the alias conversion are called alias exposure zones. T o determine if any out-of-band signals exist in the exposure zones, ru[...]

18 Figure 7. Alias Exposure Zone Checker results. The desired signal is at 150 MHz and an out-of- band signal is at –35 dBc and 642 MHz. The unwanted signal in the second alias zone is 5 dB above the –40 dBc threshold line. When no alias zones exist because the current sampling mode is alias free, no orange zone boxes will appear . In addition,[...]

19 When the original center frequency/span is inadvertently tuned to an alias response of a signal whose frequency is not the center frequency , the checker will attempt to suggest the signal’ s frequency. The checker results at the desired center frequency location (box formed by white solid and dashed lines) will show no signal, and a large sig[...]

20 Downconverting RF and Microwave Signals into the Range of the Agilent Acqiris Digitizers External components with wide bandwidths can be used to downconvert signals into the range of the broadband VSAs. The 89600 VSA software can account for the mixing equation of the external downconverter . While the downconverter cannot be controlled by the s[...]

21 PC Requirements to Run 89600 Software The 89600 requires a PC connected via the PCI extender to the Acqiris digi- tizer or an embedded PC. The PC must meet or exceed the following minimum requirements: Appendix B Characteristic Microsoft® Windows® XP Professional CPU 600 MHz Pentium® or AMD-K6 > 600 MHz Pentium or AMD-K6 (> 2 GHz recomm[...]

22 Span (Hz) Time record length (sec) Operating region Model: Acqiris U1065A (DC222, DC252, DC282) Memory: 256 Mpts and 1024 Mpts 1.E-01 1.E+00 1.E+01 1.E-02 1.E-04 1.E-03 1.E-05 5 Msa/s 10 Msa/s 20 Msa/s 50 Msa/s 100 Msa/s 250 Msa/s 200 Msa/s 500 Msa/s 1 Gsa/s 2 Gsa/s 4 Gsa/s 8 Gsa/s Minimum Time Rec Len 1.E-06 1.E-07 1.E-08 1.E +04 1.E +03 1.E +0[...]

23 For more product literature visit www .agilent.com/fi nd/89600 Related literature list 89600 Series V ector Signal Analyzers Installation and VXI Service Guide Go to www .agilent.com/fi nd/89600 then click on T echnical Support > Manuals. Understanding Time and Frequency Domain Interactions in the Agilent T echnologies 89400 Series V ector [...]

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