Search found 51 matches

by dnessett
Mon Nov 26, 2018 11:26 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Hi Gerry,

I just posted a summary of the problems I have found with the PicoScope 4262 spectrum analyzer, and which we have discussed, to the EEVBlog forum. Here is the link. I thought I would let you know in case you wished to respond there.

Regards,

Dan
by dnessett
Wed Nov 21, 2018 9:26 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Hi Gerry, I tried to open the csv file with Excel. It returned an error message, "file not loaded completely". When I looked at the results, there were only 1048576 rows. However, when I opened the file with a text editor, there were 2097151 rows, twice the number shown by Excel minus 1. For some re...
by dnessett
Tue Nov 20, 2018 11:37 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Hi Gerry, Both the psdata and csv files are too large to post to the forum (psdata is 19.8 MB and csv data is 55.5 MB). So, I have uploaded them to parking storage (google drive). The link for the csv file is https://drive.google.com/open?id=1byOrSr36wymp8do-QDh3bsHTi12aN5G2 - the link for the psdat...
by dnessett
Fri Nov 16, 2018 11:07 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Hi Gerry, For the record, I loaded PicoScope 6 onto Windows 8 (I multi-boot the machine I use for hosting the 4262). I got the same results for the csv file: >> s([1048571:1048576],:) ans = 199.999237060000013 -163.648099999999999 199.999427800000007 -162.306900000000013 0.000000000000000 -73.994619...
by dnessett
Fri Nov 16, 2018 4:24 am
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Hi Gerry, I apologize for not putting this in my previous message, but I just noticed it. The csv file produced from the 1-200KHz spectrum isn't properly scaled. Here are the first few entries: >> s([1:100],:) ans = 3.8147e-04 -1.3178e+02 5.7220e-04 -1.3512e+02 7.6294e-04 -1.3455e+02 9.5367e-04 -1.3...
by dnessett
Thu Nov 15, 2018 11:25 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Hi Gerry, You were absolutely right. There is EMI seeping into the 4262. However, I was able to isolate the problem. I ran my laptop with the USB cable supplied with the product hanging near the computer I normally used as the host. With that computer off, I did not observe any EMI interference. Wit...
by dnessett
Thu Nov 15, 2018 4:40 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Hi Gerry, Thanks. I will load PicoScope 6 on my Mac laptop, run it off the battery and see if the spurs disappear. I have found another problem, this time with the PicoScope 6 software. In order to get an accurate measurement of the spur amplitudes, I downloaded the spectrum in csv format and looked...
by dnessett
Thu Nov 15, 2018 12:36 am
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

PicoScope 4262 noise floor has significant spurs

I just purchased a PicoScope 4262. One of the first things I did was test its noise floor. I put a 50 ohm terminator on the A input and then ran a spectrum analysis. The result is shown in the first attachment. As is evident, there is a significant spur at 51 KHz. There are also spurs at ~0 Hz, ~100...
by dnessett
Fri Nov 09, 2018 11:51 pm
Forum: Getting Started
Topic: Picoscope saving multiple csv files for spectrum
Replies: 11
Views: 4138

Re: Picoscope saving multiple csv files for spectrum

Hi Gerry, I expect to get my 4262 next Monday. Would you indicate the unpublished sensitivity of this device. If a 12-bit 4224 can measure signals roughly <50 uVrms, I would expect a 16-bit to measure signals 50/16 ~ 3.125 uVrms. Of course there may be mitigating factors, which is why I am asking. A...
by dnessett
Fri Nov 02, 2018 4:37 pm
Forum: Getting Started
Topic: Picoscope saving multiple csv files for spectrum
Replies: 11
Views: 4138

Re: Picoscope saving multiple csv files for spectrum

Hi Gerry, Your statement that 12-bit scopes can only support ~50 uV finally sunk in. Since I need something that can resolve ~5 uV, the 4224 isn't going to hack it. I have two options. One is to use my Siglent for that part of the spectrum that is less than -73 dBm and the 4224 for the part greater ...
by dnessett
Fri Nov 02, 2018 12:05 am
Forum: Getting Started
Topic: Picoscope saving multiple csv files for spectrum
Replies: 11
Views: 4138

Re: Picoscope saving multiple csv files for spectrum

Hi Gerry, Thanks for your last post. I have a couple of more questions and will provide some references to information about oscillator phase noise and the experimental approaches to measuring it at the end of this message. First, I need to clear up one thing. In my last post I stated: "... the powe...
by dnessett
Thu Nov 01, 2018 12:07 am
Forum: Getting Started
Topic: Picoscope saving multiple csv files for spectrum
Replies: 11
Views: 4138

Re: Picoscope saving multiple csv files for spectrum

Hi Gerry, Thanks for clarifying what the 7 files produced under Average Display Mode represent. The oscillators I am studying in regards to phase noise resonate at 10 MHz. I think it would be helpful to very, very briefly describe the problem. I can point you to a more detailed description if you ar...
by dnessett
Mon Oct 29, 2018 8:37 pm
Forum: Getting Started
Topic: Picoscope saving multiple csv files for spectrum
Replies: 11
Views: 4138

Re: Picoscope saving multiple csv files for spectrum

Hi Gerry, Thank you for your detailed response to my questions. I very much appreciate the time you took to formulate your comments into a clear exposition of the issues. However, I am still somewhat confused about certain details, which I will pursue in this email. To clarify the discussion, I thin...
by dnessett
Sat Oct 20, 2018 12:50 am
Forum: Getting Started
Topic: Picoscope saving multiple csv files for spectrum
Replies: 11
Views: 4138

Re: Picoscope saving multiple csv files for spectrum

Hi Gerry, Thanks for the info on how the Picoscope 6 software creates the files produced by the save function. I have more experience with swept frequency spectrum analyzers (SAs) than FFT SAs. In fact the picoscope is the first FFT SA I have used. So far, I am quite impressed with its features and ...
by dnessett
Sat Oct 20, 2018 12:00 am
Forum: Getting Started
Topic: Spectrum Analyzer dBm doesn't correspond to Vp-p
Replies: 10
Views: 2537

Re: Spectrum Analyzer dBm doesn't correspond to Vp-p

That you have a project bringing parity to the Windows and Linux versions is good news. Right now I can survive with computing the power spectrum from the linear output selection, so I am able to move forward.

Thanks,

Dan