Improving Accuracy in the Readout of Resistive Sensor Arrays

Table 2

Comparison of the results obtained in an 8 × 8 array with different values of if  kΩ and the resistances of the switches take different values. (a) Classical approach. (b) ZPM circuit proposed by Wu e al. (c) Results for the proposed method in the first step. (d) Results for the proposed method in the second step.

(a) ZPM classical approach

Rns = 5 kΩ; Rs (Ω)	Error (%), (Ω)
	100	500	2000	5000	7500	10000
1	2.28	0.68	0.37	0.29	0.26	0.24
2	4.57	1.36	0.75	0.61	0.57	0.54
4	9.17	2.73	1.51	1.25	1.18	1.13
6	13.79	4.10	2.27	1.89	1.79	1.73
9	20.76	6.17	3.42	2.85	2.70	2.62
15	34.86	10.35	5.73	4.77	4.52	4.38
20	46.77	13.87	7.67	6.36	6.03	5.84
25	58.82	17.42	9.61	7.96	7.54	7.29

(b) ZPM-Wu

Rns = 5 kΩ; Rs (Ω)	Error (%), (Ω)
	100	500	2000	5000	7500	10000
1	0.14	0.14	0.13	0.11	0.10	0.08
2	0.28	0.28	0.27	0.25	0.24	0.22
4	0.56	0.56	0.55	0.53	0.51	0.49
6	0.84	0.84	0.82	0.80	0.78	0.77
9	1.26	1.25	1.24	1.21	1.19	1.17
15	2.09	2.09	2.06	2.02	1.98	1.95
20	2.79	2.78	2.75	2.68	2.63	2.57
25	3.48	3.47	3.42	3.33	3.26	3.18

(c) ZPM proposed method, 1st step

Rns = 5 kΩ; Rs (Ω)	Error (%), (Ω)
	100	500	2000	5000	7500	10000
1	0.03	0.00	0.01	0.03	0.05	0.06
2	0.10	0.01	0.01	0.03	0.04	0.06
4	0.38	0.04	0.01	0.02	0.03	0.05
6	0.80	0.09	0.03	0.00	0.02	0.03
9	1.67	0.20	0.08	0.04	0.02	0.00
15	4.07	0.55	0.23	0.16	0.14	0.11
20	6.56	0.94	0.41	0.31	0.27	0.24
25	9.39	1.43	0.63	0.48	0.44	0.40

(d) ZPM proposed method, 2nd step

Rns = 5 kΩ; Rs (Ω)	Error (%), (Ω)
	100	500	2000	5000	7500	10000
1	0.00	0.00	0.01	0.03	0.05	0.06
2	0.00	0.00	0.01	0.03	0.05	0.06
4	0.02	0.00	0.01	0.03	0.05	0.06
6	0.06	0.00	0.01	0.03	0.05	0.06
9	0.17	0.00	0.01	0.03	0.05	0.06
15	0.63	0.03	0.00	0.03	0.04	0.06
20	1.26	0.07	0.01	0.02	0.03	0.05
25	2.12	0.14	0.03	0.00	0.02	0.04