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| MrW0lf:
Now all left to do for achieving virtual MSO capability is to define trigonometric "bit extractor" functions making use of previously described floor(D) function: B0 as (cos((-((((floor(D)/(2^(0)))+(atan(1/tan(pi*(floor(D)/(2^(0)))))/pi))-0.5)+(((((-floor(D)-1)/(2^((0)+1)))+(atan(1/tan(pi*((-floor(D)-1)/(2^((0)+1)))))/pi))-0.5)*2))-1)*pi)+1)/2 B1 as (cos((-((((floor(D)/(2^(1)))+(atan(1/tan(pi*(floor(D)/(2^(1)))))/pi))-0.5)+(((((-floor(D)-1)/(2^((1)+1)))+(atan(1/tan(pi*((-floor(D)-1)/(2^((1)+1)))))/pi))-0.5)*2))-1)*pi)+1)/2 B2 as (cos((-((((floor(D)/(2^(2)))+(atan(1/tan(pi*(floor(D)/(2^(2)))))/pi))-0.5)+(((((-floor(D)-1)/(2^((2)+1)))+(atan(1/tan(pi*((-floor(D)-1)/(2^((2)+1)))))/pi))-0.5)*2))-1)*pi)+1)/2 B3 as (cos((-((((floor(D)/(2^(3)))+(atan(1/tan(pi*(floor(D)/(2^(3)))))/pi))-0.5)+(((((-floor(D)-1)/(2^((3)+1)))+(atan(1/tan(pi*((-floor(D)-1)/(2^((3)+1)))))/pi))-0.5)*2))-1)*pi)+1)/2 Set units as long name = bit, short name=B. Override range as min = 0, max=1. Fiddle with GUI to align traces: PSDATA file with environment on screenshot attached here. Found pic of some early experiment on 2205 MSO. Very clean 100kHz sine on ChB. Full 8bit AD conversion. Tech bit raw so signal is inverted and no custom probe defined. Combined with "real MSO" channels this gave 32 digitals: Might be of interest that "virtual MSO" signals = math channels can be also used as protocol decoder inputs. Note that this work is prior published on my own website: http://lab.fyi/oscilloscope_math_channels/dadc_for_picoscope_dso/index.html under CC BY-NC-SA 4.0. |
| Vtile:
Can you run some test through the PicoLog software. I have old 2203 and I'm interested how far the logging software can run with current hardware. |
| MrW0lf:
PicoLog does not seem to support new 2000, but works with my old 2205. Of course new 2000 has quite large memory but still... Simplistic PicoLog supports unlimited recording*, while PicoScope has advanced features, but no unlimited recording. Think they should add unlimited recording and logger support to both PicoLog/PicoScope, especially since TC-08 has current/voltage sensing adapter. Whole situation seems bit artificial. Like having a car with permanently locked trunk :-// *actually limitation is there, just obscured in PicoLog recording settings :( I just did never run into it with my TC-08. So I stand corrected as of today PicoScopes and some loggers that work with PicoScope software support longer logging (up to 100M or scope memory I guess). |
| MrW0lf:
Normalized amplitude and phase plot 0...100MHz on coax stub notch filter: External sweep gen used. Connoisseurs may like sample/mem settings ::) Phase unsigned much like with XY mode but no prob if have general idea whats under test. Notches bit blunted with averaging. Works fast - about 10Hz. ms=Mhz. Edit: Some x-checks... "Traditional" Pico freq response plot obtained with FFT, no phase data this way but amplitude minimums accuracy better: RFExplorer trying the same. Have no suitable attenuator so had to crank down signal gen, which may account for some little differences: Overall seems new method is usable. Can obtain general picture with phase data and then more accurate amplitude with FFT afterwards, if needed. Shall contrapt some more x-checks and then explain how new method works. |
| MrW0lf:
Further dev of math based bode plotter using ext gen. Check against actual bode plotter software: First did download helpful SDK-based utility called FRA4PicoScope that employs internal gen on 2000. Plot on some DIY BPF from 20kHz to 1MHz, 10dBm in. Works well, all by the book: Next same using external gen (Siglent SDG2000X) with MCFRA (Math Channel FRA), all params same: Since cannot force log time on horizontal used freq plot (green) and cursors instead. Pick freq on green trace with horizontal cursor. Place vertical. Place further horizontal ones to get all the readings. Cross check on actual trace on the right confirms all correct. Toying with severe subsampling to gain speed sometimes works sometimes not. Easy to detect by "ghosts" on phase plot (not pictured in this example). Phase unsigned as usual. Overall seems success then. Good enough for DIY extra functionality. Now some tests at the top of analog bw and then finally explain procedure... |
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