Is there possible to compress data to store more values?
Could you please specify more detailed the problem with the current method to save data.
Please specify also your oscilloscope type (PCS…?).
I sometime use the scope to measure digital signal and the memory is to low to get good values. Is it possible to make some compresson of values so it can store more data? If you have like values 25,24,25,24,26,23,25,160,162,161,162,160 store all 20-30 a bit(0) and a short to tell many value it contain(lenght) and 155-160 as bit(1) … Understand the idea? Sorry if my english is bad. Or you can make like I did whit a VB app you define values for start-bit, stop-bit, 1-bit and 0-bit so instead of geting wave forms you can get data like “01000111000111” so you can easy read out for example IR protocolls or what ever.
You are right that manipulating the data before it is stored to the internal RAM of the scope it is possible to store more samples. Easiest way is to reduce the number of bits. In theory digital data can be saved 8 x 4096 samples per channel.
This may be interesting feature that may be considered for possible future products anyhow.
Actually it is more or less like a logic analyzer feature for the scope…
Yes but you it would be a nice to use your scope as a logic analyzer to. Many hobbyist have not afford both scope and logic analyzer so in the end I think you will get more customer.
The problem as a logic analyzer is that there are only two cannels + external triggering input available. Maybe there is some use for this kind of “mini” logic analyzer anyhow…
Thank you for your comments and interest to improve these products.
I believe such a logic analyzer mode would be a great addition (I could use it right away - I’m running into the same problem, too short record length for my digital data stream).
One possibility could be to have the user set up the scope normally (trigger level and source, channel gain and offset), then let the user choose a digital threshold for each channel (CH1 and CH2); e.g. with a slider bar like the ones for offset and trigger level. Now when the user switches into “logic analyzer” mode, the scope would only store 1 bit per sample, a “0” if the digitized value is below the threshold, a “1” if it is above), and display it normally on the screen (but with only two possible levels).
Doing that would require minimum changes to the user interface, plus very limited change to the scope firmware.
Thank you for this comment.
Yes, this kind of logic analyzer function could be really a big improvement to the functionality of the PCSU1000 oscilloscope.
To keep things simple, I think that the digital thresholds will be put at fixed levels: For CH1 in the middle of the upper half of the screen and for channel 2 in the middle of the lower section of the screen.
The resulting digital waves are also displayed corresponding in the upper and lower half of the screen in fixed place and with fixed amplitude.
I think it is no problem for advanced user to use this kind of simple logic analyzer. The most important thing is that this way the amount of samples will be increased from 4k to 32k per channel.
Hi VEL255,
that sounds like a pretty good approach, it keeps the setup simple. Just make sure the help function clearly documents it.
Please keep us posted as to when this new feature becomes available!.
Also, any chance the double-rate trigger will be included as well (to reduce the trigger jitter at fast timebase setting)?
Wolfgang
Now the logic analyzer feature is added to the PCSU1000 oscilloscope.
Long sequences of digital data can be captured to the acquisition RAM of the scope. On each sample the input signal level is detected. If it is over the pre-defined threshold then “1” is stored to the RAM. If the signal is below the threshold then “0” is stored. This way each sample takes only one bit of the memory capacity. This way the number of samples stored to the memory is 32768 samples per channel (in oscilloscope mode it is 4096 samples).
How to use:
In oscilloscope mode use the vertical position sliders to adjust CH1 signal to the middle of the upper half of the screen and CH2 to middle of the lower section of the screen.
Click the check box “Logic Analyzer”.
The signal is displayed with fixed height on the screen.
Here are some images:
Normal oscilloscope view:
Same signal displayed in the logic analyzer mode:
In this example there are captured sequence of 512 bytes of serial data.
In this image the six last bytes of the sequence are displayed using the zoom function (adjusting time/div setting).
Signal zoomed to see the last byte of the sequence:
You can download the files from: vel255.diinoweb.com/files/PCSU10 … alyzer.zip
Extract the two files to the folder \Program Files\Velleman\PC-Lab2000SE.
On the startup screen of the PC-Lab2000SE select both PCSU1000 and PCGU1000 to start the modified program PCSU1000GU.EXE.
Wow, that was quick! Thanks a lot!
This is something I’ve always wanted… 
Thanks for your fast support:D
This is indeed a very nice tool. Thank you sdujolo and womai for the idea to do this!
Now the program is somewhat better. The horizontal scroll with maximum zoom is now smoother with a wheel mouse.
Also the waveform display is enhanced.
Now the program for the combination PCSU1000 + PCG10 is also included.
If you have only PCSU1000 you can now select it at the startup screen.
Sorry, womai, there is not the 100MHz triggering detection (yet). I think the jitter can’t be removed even if the triggering event is detected at double sample rate. Still the time from the triggering point to the next sample varies 0ns to 20ns and this causes the jitter. I think using the average is the best way to reduce the triggering jitter…
You may download the latest test version of the software from: vel255.diinoweb.com/files/PCSU10 … alyzer.zip