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Bottom Layer |
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Top Layer |
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SNR |
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CMRR |
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Frequency response |
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Stopband attenuation |
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other electrical characteristics |
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Hardware The changes between V1.2 and V1.3 concerns only the USB controller and an added P-MOSFET. Since I have had more pcbs manufactured than I have used some are still left. So if you wish to obtain an empty board please feel free to contact me |
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Specs As is the case for the version 1.2, I measured three monoliths of the version 1.3. |
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For measuring the SNR four EEG inputs were each connected via a 10k resistor to the DRL |
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Signal to Noise Ratio (SNR) |
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The CMRR was measured at 50mVpp, 10Hz over 10k resistors connected to the EEG inputs |
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Common mode rejection ratio (CMRR) |
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The CMRR was not measurable against DRL with the available equipment and was thus assumed to be below the noise threshold. |
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frequency response measured in Hz |
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Damping of aliasing frequencies measured in dB |
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MonolithEEG V1.3 |
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Under contruction |
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In relation to the frequency response, B was not a lot better than A. On the other hand, construction unit tolerances play a stronger and unfavourable role. With the frequency response B, the Sallen key low-pass is driven more strongly into resonance. The three test monoliths can be regarded as successful, but I would not guarantee unrestricted repeatability. I would, therefore, recommend the frequency response A for the monolith. |
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EEG input voltage range |
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±250uV |
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Maximum offset voltage at 100nA |
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±140mV |
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Resolution |
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10 Bit / 0.5uV |
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Effective resolution |
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9 Bit |
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Noise |
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1uVpp |
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current consumption |
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60mA |
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Supply voltage |
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4.5 - 5.5V |
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Damping |
#1 CH1 |
CH2 |
#2 CH1 |
CH2 |
#3 CH1 |
CH2 |
Mean |
Simulation |
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-3dB HP |
0.26 |
0.29 |
0.27 |
0.26 |
0.25 |
0.27 |
0.27 |
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-1dB HP |
0.49 |
0.51 |
0.48 |
0.47 |
0.45 |
0.50 |
0.48 |
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-1dB LP |
57 |
52 |
54 |
52 |
54 |
53 |
54 |
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-3dB LP |
64 |
61 |
62 |
61 |
62 |
62 |
62 |
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Aliasing frequency |
#1 CH1 |
CH2 |
#2 CH1 |
CH2 |
#3 CH1 |
CH2 |
Mean |
Effective Bits |
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128Hz |
-24.4 |
-24.4 |
-24.4 |
-24.6 |
-24.4 |
-24.4 |
-24.4 |
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256Hz |
-49.0 |
-49.1 |
-49.0 |
-49.2 |
-50.4 |
-50.2 |
-49.5 |
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300Hz |
-55.5 |
-55.1 |
-55.4 |
-55.4 |
-55.5 |
-55.5 |
-55.4 |
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512Hz |
-80.0 |
-80.0 |
-78 |
-78 |
-78 |
-78 |
-78.7 |
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# |
Channel |
Measured against VGND |
Measured against DRL |
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1 |
1 2 |
8.9uVpp / -75dB 8.4uVpp / -75dB |
<1uVpp / <-94dB <1uVpp / <-94dB |
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2 |
1 2 |
9.7uVpp / -75dB 10uVpp / -74dB |
<1uVpp / <-94dB <1uVpp / <-94dB |
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3 |
1 2 |
9.7uVpp / -75dB 9.0uVpp / -75dB |
<1uVpp / <-94dB <1uVpp / <-94dB |
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# |
uVpp |
SNR |
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1 |
1 |
-54 |
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2 |
1 |
-54 |
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3 |
1 |
-54 |
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Aliasing frequency |
Simulation |
Effective Bits |
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128Hz |
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256Hz |
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300Hz |
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512Hz |
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