Search found 51 matches

by dnessett
Wed May 01, 2019 11:00 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, ... However, if you are making the measurements w.r.t. 1mW dissipated into a load for dBm, and your load is 50Ω then you need to make the necessary correction to the measurement, in particular, if you want to use a voltage reference then the ref for a 50Ω load will be √(50 * 0.001) = 0.223...
by dnessett
Tue Apr 30, 2019 11:42 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 figured out the problem in my conversion program. I was first converting dBV to millivolts by dividing the dBV value by 20, exponentiating 10 by this value, and then multiplying by 1000. To get power I squared the result and divided by 50. This is obviously incorrect. Power is voltage sq...
by dnessett
Tue Apr 30, 2019 12:33 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 Dan, Have you corrected for Process gain (I couldn't find any reference to it any of your links)? If not then go here to find out how to correct your data: https://www.picotech.com/support/topic25101.html?&p=86081&hilit=process+gain#p86081 Regards, Gerry Hi Gerry, I did not correct for processin...
by dnessett
Sat Apr 27, 2019 4:29 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 wanted to characterize the noise floor of the PicoScope 4262 in terms of dBm@50 ohms. Since my version of PicoScope 6 runs on Linux and that version doesn't support displaying dBm@ 50 ohms, I saved the data in csv format and, using Octave, converted it to the desired form. Here is the gr...
by dnessett
Thu Apr 25, 2019 8:35 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Coincidentally, my mother did exactly the same thing a number of years ago and had to have a replacement. The most important thing that I learned from was that was that the rehabilitation (physio-therapy) after that is so critical to getting them back to their mobility (even if they don't have much...
by dnessett
Sun Apr 21, 2019 5:28 am
Forum: Getting Started
Topic: Corrections for Windowing functions in FFT calculations
Replies: 14
Views: 3601

Corrections for Windowing functions in FFT calculations

Hi, This is really not a "getting started" sort of question, but I could find no other board to use in asking it. When the PicoScope FFT spectrum analyzer is applied to an input signal, there is the option of selecting a window function to reduce spectral leakage from one bin to another. A general d...
by dnessett
Sat Apr 20, 2019 3:39 pm
Forum: PicoScope for Linux
Topic: Feedback wanted from our Linux users!
Replies: 11
Views: 5241

Re: Feedback wanted from our Linux users!

Hi Kieran, I posted a response to this question a day or two ago, but was at the time concerned with PicoScope 6 becoming non-responsive. This is obviously a bug and doesn't really address your feedback question. So, let me add one thing. The major enhancement I would like to see is ensuring the Win...
by dnessett
Fri Apr 19, 2019 4:31 am
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Thanks Gerry.

I have had to take some time off as my mother fell and broke her hip. Helping her with rehabilitation has taken a lot of my time. So, I didn't visit this forum for a while, which is why this response is so late.

Cheers,

Dan
by dnessett
Thu Apr 18, 2019 2:14 am
Forum: PicoScope for Linux
Topic: Picoscope 6.13.7.707 sometimes just stops responding
Replies: 1
Views: 746

Picoscope 6.13.7.707 sometimes just stops responding

I have again experienced the Picoscope 6.13.7.707 beta software becoming non-responsive. I originally reported this behavior as a problem using a 100 Hz frequency span (see https://www.picotech.com/support/topic39790.html ) and I later thought the problem was operator error (selected single triggeri...
by dnessett
Wed Apr 17, 2019 8:26 pm
Forum: PicoScope for Linux
Topic: Picoscope6 Beta - 100 Hz Frequency Span not working
Replies: 1
Views: 691

Re: Picoscope6 Beta - 100 Hz Frequency Span not working

Nevermind - operator error. Somehow I managed to set the trigger to "single". Sorry to bother everyone.

Dan

Added later (4-20-2019): Well it seems it wasn't "operator error" after all. See my subsequent post topic39791.html.
by dnessett
Wed Apr 17, 2019 1:23 am
Forum: PicoScope for Linux
Topic: Picoscope6 Beta - 100 Hz Frequency Span not working
Replies: 1
Views: 691

Picoscope6 Beta - 100 Hz Frequency Span not working

Hi, I am trying to display the spectrum of a signal using a frequency span of 100 Hz. I select 100 Hz, use 1024 bins and press start. The properties panel shows a gate time of ~10 seconds. But, in fact nothing happens. I waited over a minute in case there was some sort of startup problem, but no luc...
by dnessett
Tue Feb 12, 2019 12:26 am
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Gerry doesn't seem to be responding. Anyone else know the answer to my question?

Thanks,

Dan

Posted later: Oops. Didn't see Gerry's reply as it was on the second page. My apologies.

Dan
by dnessett
Thu Jan 24, 2019 8:46 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 have a quick question. The procedure for adjusting measurements made by a low frequency spectrum analyzer when used by the HP111729c include adding in the insertion loss due to any log-amps at the front-end of the analyzer. For the HP spectrum analyzer specified in the HP11729c operation...
by dnessett
Thu Dec 06, 2018 8:49 pm
Forum: Getting Started
Topic: PicoScope 4262 noise floor has significant spurs
Replies: 26
Views: 6170

Re: PicoScope 4262 noise floor has significant spurs

Thanks Gerry,

Regards,

Dan
by dnessett
Thu Nov 29, 2018 12:00 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 thought I had resolved all of the issues I ran across when viewing the noise floor of the PicoScope 4262 in spectrum mode. However, I now realize one issue remains. The csv file contains two segments that repeat the spectrum from 0 Hz to (N/2)-1 Hz (the first segment drops the first 2 bi...