Table 3. Precision of the determination of J_NH from spectra with different kappa shifts.

Precision of the determination of J_NH from spectra with different kappa shifts as a function of signal to noise ratio. Peak intensities and linewidths were taken from Table 1, 800 MHz, τ_c 20 ns. The data was simulated using the routines simTimeND, addNoise and NmrPipe. The peak picks and S/N calculations were carried out with Sparky.

Kappa	S/Na	Normalized Shiftb	Max-Minc	S/N	Normalized Shiftb	Max-Min	S/N	Normalized Shiftb	Max-Min
0.00	154.00			91.00			65.00
0.20	71.33	90.07	1.32	43.33	89.93	1.73	31.33	92.07	5.08
0.40	51.00	89.61	1.53	30.67	90.22	2.19	21.67	86.56	3.41
0.60	37.67	90.14	5.97	23.33	87.68	7.42	15.00	89.25	1.66
0.80	32.67	91.24	0.74	17.33	87.10	5.03	13.67	93.51	2.77
1.00	27.00	91.36	2.32	16.67	89.51	8.97	14.00	93.28	4.07
1.20	20.67	90.85	4.69	14.33	92.07	2.31	10.67	89.45	7.02
1.40	20.67	89.65	1.03	13.67	88.42	2.60	9.67	85.87	5.96
1.60	19.33	91.07	1.78	11.33	88.42	8.08	10.00	90.96	7.16
1.80	18.00	92.29	0.23
2.00	16.67	88.68	7.04
Kappa	S/N	Normalized Shiftb	Max-Min	S/N	Normalized Shiftb	Max-Min	S/N	Normalized Shiftb	Max-Min
0.00	45.67			37.00			28.00
0.20	21.33	87.15	5.69	13.67	90.68	3.97	13.33	84.61	5.39
0.40	16.33	91.05	7.12	14.00	88.02	8.44	10.67	91.75	6.71
0.60	13.00	89.91	4.64	11.67	94.20	9.73	9.00	85.44	13.90
0.80	10.00	90.11	2.14
1.00	10.00	90.66	14.12

^a)The average Signal-to-noise ratio of the kappa-shifted peaks in three simulated spectra.

^b)the normalized shift was calculated as (peak(kappa) – peak(0))*2/kappa*90., where peak(kappa) is the average peak-pick position in three simulated data sets with approximately the same noise level. The position peak(0) was taken from noise free data for all calculations.

^c)The differences between the maximum and minimum values for the shift, as computed for the three spectra. This is a crude measure of the statistical error in the peak pick.