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Tradeoff: Dynamic range and bandwidth in signal analysis

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Stanley22
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
Stanley22   1/27/2011 11:47:05 PM
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Thanks for your comments and insights into the limitations of modifying the test configuration. Also, I should have written “reduce the noise floor or improve the dynamic range” instead of using “and”. I agree that the best alternative, if budget allows, is to use an analyzer with the best specs in terms of DANL (Displayed Average Noise Level) and SFDR (Spur Free Dynamic Range). A feature that can further reduce the noise floor that I didn’t mention in the article comes with the Agilent PXA signal analyzer. It's feature called Noise Floor Extension that uses a noise subtraction technique that can significantly improve noise performance for some applications. More information can be found at: http://cp.literature.agilent.com/litweb/pdf/5990-5340EN.pdf Thanks, John Hansen

agk
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
agk   1/26/2011 5:38:24 AM
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The sampling and processing of the signals add to the noise floor easily. If the signals are processed in the analog domain itself the dynamic range cane be further increased and the noise floor can be reduced.This calls for very good analog design practices.

Sanjib.A
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
Sanjib.A   1/25/2011 5:54:06 PM
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Hi John! Thank you for replying and providing the link to the application notes on the topic of probing practices and measurement techniques I was looking for. Thanks a lot!

Stanley22
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
Stanley22   1/25/2011 5:30:04 AM
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By the way,if you have additional questions feel free to contact me at: john_s_hansen@agilent.com Thanks, John Hansen

Stanley22
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
Stanley22   1/25/2011 4:57:01 AM
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You bring up a really important issue. When probes are used they represent the single largest factor in determining the noise floor of the measurement. There are many excellent resources that discuss probes and probing techniques in detail on the Agilent website at this link: http://www.home.agilent.com/agilent/product.jspx?nid=-536902770.0.00&c=153344.i.2&to=79831.g.1&cc=US&lc=eng&pageMode=LB&sortKey=date Thanks, John Hansen

Stanley22
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
Stanley22   1/25/2011 3:38:27 AM
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The software shown here is Agilent's 89600A vector signal analysis software. It can be used with most of Agilent's analysis platforms including spectrum/signal analyzers, oscilloscopes and logic analyzers. It can be purchased as an option to run on our PC based analyzers and scopes but only operates with Agilent hardware. A new version has just been released (89600B) which provides a much more flexible user interface and has a greater ability to demodulate & analyze custom waveforms as well as standardized ones. More information about the new version (and a 14 day trial license) can be found at: http://www.home.agilent.com/agilent/product.jspx?nid=-33713.958604.00&cc=US&lc=eng or www.agilent.com/find/vsa

RF_fan
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
RF_fan   1/24/2011 3:31:45 PM
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I have following comments on the proposed measures to increase dynamic range. 1. Reduce the analyzer attenuation I assume the author refers to RF attenuation, which is available on signals analyzers. It has no effect on the dynamic range at all. It reduces the noise floor and reduces the maximum level at same time. 2. Add a preamp (which can be included with the analyzer) Yes, a preamp reduces the noise floor, but it also adds noise due to its non-zero Noise Figure. According to the Friis formula, the reduction of noise by a preamp is always less than its gain, even if the premp is noiseless. Maximum level is reduced by the gain, however. The result is always lower dynamic range. 3. Reduce the resolution bandwidth (RBW) of the analyzer Yes, lower resolution bandwidth is a means to reduce the noise floor. However, it most cases it is not possible to reduce resolution bandwidth due to the nature (e.g. bandwidth) of signal to measure and due to the bandwidth required by standards, e.g. for adjacent channel power measurement. 4. Add external filtering External filtering can increase dynamic range in specific cases, e.g. by using a high-pass filter with measurement of harmonics 'or using a band-pass filter when measuring out of band spurious. However, it is always signal specific and must be designed from case to case. I think its not a very economic way, to increase dynamic range. My conclusion: If I need dynamic range the use of an analyzer with high inherent dynamic range is the only choice I have.

Sanjib.A
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
Sanjib.A   1/22/2011 12:27:00 PM
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Thanks for the valuable information provided in this article. I am also interested to know the details about the probe hardware’s those should be used for the measurement and the best practices one we should follow to make an accurate measurement.

elctrnx_lyf
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re: Tradeoff: Dynamic range and bandwidth in signal analysis
elctrnx_lyf   1/22/2011 7:28:29 AM
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Thans for providing the article on the VSA software. I want to know if this software is comercially available from Agilient. Even though i have used used a dedicated VSA equipment with many 2G, 3G software applications installed. This is the first time I'm coming across a VSA software application that can be used from a oscilloscope. Is this software can be installed in all the high end oscilloscopes irrespective of the vendor?

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