A 12-bit ADC that rounds to the nearest code has an input range of 0 to 1 V. With 1 LSB = VFSR/2ᴺ, find the largest quantisation error eq,max in mV.
Data acquisition & sampling worksheet with answers
An 8-bit ADC has an input range of 0 to 10 V. Taking 1 LSB = VFSR/2ᴺ, find the size of one LSB in mV.
A 23 kHz sine wave is sampled at 20 kHz without an anti-aliasing filter. At which frequency fa does it appear in the samples? Give it in kHz.
A sensor measures pressure over a span of 500 kPa, and its output fills the whole input range of an ADC. The reading must resolve 1 kPa. Find the smallest number of bits N the ADC needs.
A 4.4 kHz square wave is sampled at 20 kHz with no anti-aliasing filter. A square wave contains the odd harmonics 3f₁, 5f₁, 7f₁, … At which frequency fa does its harmonic 5f₁ appear in the sampled data? Give it in kHz.
A temperature sensor gives 10 mV/°C (0 V at 0 °C). Its signal is amplified 10 times and fed to an 8-bit ADC with a range of 0 to 5 V (1 LSB = VFSR/2ᴺ). Find the temperature change ΔTLSB that corresponds to one LSB.
Answer key
- 1. eq,max = 0.1221 mV
- 2. 1 LSB = 39.06 mV
- 3. fa = 3 kHz
- 4. N = 9
- 5. fa = 2 kHz
- 6. ΔTLSB = 0.1953 °C
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