44 lines
1010 B
Plaintext
44 lines
1010 B
Plaintext
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Some processing thoughts:
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zcat log.gz | grep ^1 | tail -n +200000 > log-locked
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octave:
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a=load("log-locked");
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len=size(a,1)
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t=1:10000;
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keith=a(:,3);
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calib=a(1,4)
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dac=a(:,5);
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adc=a(:,6);
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meas=-(dac - calib * adc);
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plot(keith(t),meas(t)) # should be linear
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p = polyfit(keith, meas, 1)
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plot(t,keith(t) * p(1) + p(2),t,meas(t)) # should match
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t=1:len;
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plot(t,keith(t) * p(1) + p(2) - meas(t)) # absolute error (units=dac)
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axis([0 len -1 1])
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Range is something like +- 0.5 over the entire range (of "DAC values")
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This gives log(1024 / 1.0) / log(2) = 10 bits
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No good!
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Now let's convert the DAC values to their more-accurate value using the lookup table
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lookup=load("../../../firmware/lookup.inc");
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size(lookup)
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meas=-(lookup(dac + 1)/64 - calib * adc);
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p = polyfit(keith, meas, 1)
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t=1:len;
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plot(t,keith(t) * p(1) + p(2) - meas(t)) # absolute error (units=dac)
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axis([0 len -0.3 0.3])
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Now closer to +- 0.05
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This gives log(1024 / 0.1) / log(2) = 13.3 bits
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