A strain-gauge signal of interest lies between and and is logged with a -bit…

PHYSICS · Multi-part · Fermi University Physics · Electronics, Instrumentation & Communication · Digital electronics, embedded systems and data acquisition · Digital electronics, embedded systems and data acquisition

Electronics for Measurement, Ch Sampling, quantisation and the acquisition chain

Problem

A strain-gauge signal of interest lies between

0

and

400\,\mathrm{Hz}

and is logged with a

10

-bit converter sampling at

f_s = 1\,\mathrm{kHz}

, with no anti-alias filter fitted. The bench supply couples in an interference tone at

950\,\mathrm{Hz}

. A colleague argues: "

950\,\mathrm{Hz}

is well above our

400\,\mathrm{Hz}

band of interest, so it cannot affect our reading; and if the record still looks noisy, we should simply fit a

16

-bit converter instead." ((a)) Find the frequency at which the

950\,\mathrm{Hz}

interference actually appears in the logged record. ((b)) State whether fitting a

16

-bit converter would remove this error, and why.

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