DSP Quantisation
1. An analogue signal is to be sampled from a transducer with an output voltage range of 0 to 10 volts and operating on a 12-volt power supply. The designer has available two analogue to digital converters (ADC): a 3 bit ADC and a 4 bit ADC. For each converter:
(a) Supply the quantisation levels (including zero) that are available. Do this for both the three and 4-bit ADC in table form.
(b) What is the resolution of each quantizer?
(c) What is the maximum quantisation error?
Solution Preview
(a)
quantisation levels: (assuming a linear ADC)
3-bit ADC: 2^3 = 8 levels (level 0 to 7); divide 10V by (8-1=) 7 since 0 V represents level 0 and 10 V represents level 7.
Bits
2 1 0 QU. Level(V)
- - - ------------
0 0 0 0.0
0 0 1 1.43
0 1 0 2.86
0 1 1 4.29
1 0 0 5.71
1 0 1 7.14
1 1 0 8.57
1 1 1 10.0
4-bit ADC: 2^4 = 16 levels (level 0 to ...
Solution Summary
The solution gives clear steps to finding the quantisation levels (three and 4-bit ADC in table form), resolution of each quantizer and maximum value of the quantisation error for the analogue-to-digital converter described.