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keshuaixu / dvrk-s-pwm

H-bridge motor drivers for dVRK-S
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Use stronger AA filter #9

Closed keshuaixu closed 2 years ago

keshuaixu commented 4 years ago

The Source of the noise seems to come before the ADC. Shorting the INA240 input only minimally reduced the noise.

200ohm/120pf -> std 12.256519504329113 = 3.6154774485712298 bits 4k/120pf -> std 5.5361214979442055 = 2.46887560528644 bits 4k/0.1uf -> std 0.6125852103993371 = -0.7070175584126178 bits 260.482kHz 1.3kΩ 470pF -> std 5.6258684805103645 = 2.492075826251382 bits 130kHz 1.3kΩ 1000pF -> std 4.307256109172057 = 2.1067691086848064 bits

Current signal frequency: LC 1ohm 1mH -> 160 Hz. max capacitive load of INA240 = 1nf.

keshuaixu commented 3 years ago

need to update schematic

keshuaixu commented 3 years ago

ch 1 and vm has 10nf filter

keshuaixu commented 3 years ago

channel B3 has 406kHz 392Ω 1000pF