Using the tinySA Ultra to measure the Noise Figure of an amplifier.
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- เผยแพร่เมื่อ 28 ส.ค. 2024
- This video demonstrates how to use the tinySA Ultra to measure the Noise Figure of an amplifier.
For more info on the tinySA products go to: www.tinysa.org...
Thanks Erik. I really appreciate these 'how to' videos. They expand on what I can do with the TinySA almost as if each video were adding a feature. But the fact is, I simply wouldn't know how to use some of the features without your demonstration videos.
Something I just ran into testing an older amplifier designed for 2m weak signal. I checked the gain using a signal generator and the tinySA. I arbitrarily chose -40db as the amplifier input for the measurement and ended up with a vastly higher noise figure on the Tiny than my HP 8970A indicated. I retested the amplifier but this time I used a -100dbm signal at the input of the amplifier. The gain value was different the amplifier obviously starting to compress at the -40dbm level. The result of measurements with the new gain value were TinySA ultra 0.4db and HP8970A 0.42db. I have to say, I am getting more and more impressed with the TinySA ultra.
Thanks Erik for the invitation
Thanks for share and nice glassed 😉😸
Thanks so much for posting all your Very helpful TinySA informative videos.....Could you explain why a properly designed matched 50 ohm Rf amplifier under test NF Significantly Improved to 1.5 db when Un-terminated ?? ....I was Expecting the Un-terminated amplifier to Significantly Degrade to higher than when properly 50 ohm terminated .....Thanks...
Look here: www.analog.com/en/technical-articles/lownoise-amplifier-lna-matching-techniques-for-optimizing-noise-figures.html
Amazing noise power Matching info !!! .......A properly 50 ohm input Terminated RF Amplifier generates slightly (about 3 db) More noise than an Input Un-terminated amplifier.....Of course neither an input Shorted or input Un-terminated Amplifier is useful....Maybe some kind of cleaver "tricky" input to output Feedback scheme could produce a "Noiseless" 50 ohm Input termination ???
Are you Sure that it isent the thermal noise from the 50 ohm load that you ar measuring when you measure more noise
Hi are you shure that it isent the thermal noise from the 50 ohm load that you are measuring when you measure higer noise level
Please join groups.io/g/tinysa for technical discussion
Would it be advisable to use the same termination for both measurements or is the error small enough to be ignored if using different 50 ohm terminations?
You can use different terminations as a couple of ohm does not make a difference. But for high frequencies, above 1GHz, you better use the same as the complex impedance van be very different.
@@ErikKaashoek Thank you Eric, that is what I thought. I just tested an amplifier I build a while ago on 144.2Mhz. With the TinySA ultra the indicated noise figure is .4dB, with my 8970A the indicated noise figure is .42dB. Impressive result for the ultra, well done.
Can the same PC software as for the tinySA be used with thus ultra version?
-170 dBm/Hz noise floor for the tinySA seems a little too low. Is that accurate?
It is accurate due to the excellent internal LNA with a noise figure of about 4., above 750MHz the noise floor starts to increase
@@ErikKaashoekThanks for the reply. That's very impressive. Is the project open source?
@@couplingconstant The SW is open source, the HW not. See the wiki at tinysa.org
I have a tinySA ultra and if I measure the NF of an amplifier I get negative value, like NF: -3.6. The values I am measuring looks valid if I omit the minus sign. I have the latest firmware V1.4.129 on the SA. Could this be an software issue?
Just to cross check I measured a mini-circuit LNA gain with a professional SA, and what I got is inline with the value measured with tinySA and with the datasheet too. So I am confident that I input the correct gain when it is asking for it. Also the measured NF is very close to the value from datasheet.
Did you always terminate the input with a 50 load?
Yes
I just checked github issues, and I found a bugticket with the same issue.
Does the TinySA Arrive Out of the Box already Factory Level Calibrated ?
Yes and no. The frequency dependent part is calibrated but the absolute level can be calibrated using the built-in very accurate calibration source.
Erik, is it possible to get the stored .csv traces on the sd card to the pc app for further exporting to another program?
Not yet. I hope to add the ability to use the SD card as a USB drive from the PC
Thanks for your prompt reply and overall support. This feature is major for audiovisual applications such as site surveys for posterior frequency coordination. This would exempt the user from bringing a laptop just to export csv.
@@lisbom2001 I may have misunderstood your question. It is already possible to store a trace in .csv format on the SD card. Once back hope you can extract the SD card and use a PC to read the stored files on the SD card
@@ErikKaashoek but where on the pc app?
@@lisbom2001 The PC app can not extract traces stored on the SD card from the SD card
Yes
Erik, I'm using my tiny sa ultra to catch any distorced harmonics from a PGA113, which signal is 200khz square. I've noticed that if the tiny sa ultra is connected to the output of the PGA113, the sinusoidal gets distorced. If I take off the tiny sa ultra, it keeps a clear sin. Do you have any clue if it's an defective unit of tiny sa ultra?
@@Ech01378 Join groups.io/g/tinysa for detailed support questions
Hi