[HN Gopher] Taylor Series and Accelerometers
       ___________________________________________________________________
        
       Taylor Series and Accelerometers
        
       Author : signa11
       Score  : 18 points
       Date   : 2020-08-12 08:55 UTC (14 hours ago)
        
 (HTM) web link (jeremykun.com)
 (TXT) w3m dump (jeremykun.com)
        
       | [deleted]
        
       | kayson wrote:
       | Using differences to avoid non-linearity is a pretty common
       | technique used across EE, especially circuit design. Transistors
       | are very non-linear and circuits like amplifiers have problematic
       | squared terms. However, they're almost always built
       | "differentially": there are both positive and negative input
       | terminals, and positive and negative output terminals. The
       | difference of the output voltages is an amplified version of the
       | difference of the input voltages. Because the squared term at
       | each terminal is the same polarity, subtracting them cancels it
       | out very well. In practice, you're limited by how well the
       | positive and negative paths match, and the mismatch allows some
       | second order term to leak out. Unfortunately, this does not help
       | with the third order terms.
       | 
       | See: https://en.wikipedia.org/wiki/Differential_amplifier
       | https://en.wikipedia.org/wiki/Third-order_intercept_point
        
       | ISL wrote:
       | To answer the post's final question: Yes. It is quite common to
       | design instrumentation to cancel systematic uncertainties or
       | nonlinearities to leading order. Fancier arrangements go to
       | higher orders.
       | 
       | In the particular case of the differential capacitor, that form
       | of differential measurement is particularly common -- if one non-
       | linear system can paired with a symmetric partner with equal and
       | opposite nonlinearity, the leading-order non-linearities are
       | suppressed (to the extent that the matched pair are actually
       | matched).
       | 
       | An easy-to-understand example of the compensation of linear
       | effects is the temperature-compensated pendulum clock:
       | https://en.wikipedia.org/wiki/Gridiron_pendulum
        
       ___________________________________________________________________
       (page generated 2020-08-12 23:00 UTC)