FFT Spectrum Analyzer

Which product is right for your exact requirements
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Joined: Fri Aug 06, 2021 11:11 am

FFT Spectrum Analyzer

Post by ZeusMC »

I'm interested in making vacuum tube guitar amplifiers. A FTT spectrum analyzer would be useful.
I would like to know if the functions, features of the Picoscope FFT spectrum analyser are comparable with the HP 3582A Spectrum Analyzer?

HP specification see here, https://www.avionteq.com/document/3582A ... -sheet.pdf

Also specification information here, https://www.testequipmentdepot.com/used ... /3582a.htm

Which of the lower priced Picoscopes would be suitable?

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Joined: Mon Aug 11, 2014 11:14 am

Re: FFT Spectrum Analyzer

Post by Gerry »

Hi ZeusMC,

I apologise for the long delay in answering, I have been tied up with other work, so I haven't been able to answer forum posts for quite a while.

To answer your question, yes, the PicoScope 6 Spectrum Mode, for PicoScopes is comparable to the HP 3582A Spectrum Analyzer. The Spectrum Mode can do nearly all of what the Signal Analyzer can do but better (or a complete comparison see the end of this post). PicoScopes can also be controlled by user created software offering many more functions and capabilities than the freely available PicoScope 6 software, such as the FRA4PicoScope Frequency Analyzer software, available here: https://bitbucket.org/hexamer/fra4picoscope/wiki/Home. As you can see this 3rd party software gives you the capability to perform frequency and phase analysis of DUT's.

The only advantages of the Signal Analyzer are the Coherence function, and the ability to plot Phase Spectra, as our Spectrum Plot only displays Frequency Spectra.

Full comparison
All PicoScopes (excluding the PicoScope 2204A and 2205A) have significantly higher Frequency resolution than the Signal Analyzer. The PicoScope 4262 has a Frequency resolution of 95uHz, while the Signal Analyzer only has 1Hz resolution. Both devices can be configured to process low frequency spectra, such as audio, well. The PicoScope will be much faster at computing FFT's than the Signal analyser, as it uses the full processing power of your computer versus the limited processing available in the stand alone Signal Analyzer. The Signal analyser Dynamic Range is only 70dB, while the Dynamic Range varies from 44dB for 8-bit PicoScopes, to typically 70dB for 12-bit PicoScopes, and on to 70-95dB for 16-bit PicoScopes. The Signal Analyzer can capture Transients of a few ms, while a PicoScope can capture Transients between 1us and 1ns depending upon the model. A PicoScope can remove the noise floor of a Spectrum so that you can actually see frequency components that would be buried in the noise (using coherent gain).

Regarding which would be the correct PicoScope for your measurement application with Valve Amplifiers, I would suggest the PicoScope 4262 as it has the best dynamic range of all of our PicoScopes, and covers the complete audio bandwidth for signal analysis. However, I would also recommend using the correct probes for it when measuring high voltages on Valves (see here: https://www.picotech.com/accessories/ac ... gh-voltage).


Technical Specialist

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