MLX90365 Datasheet, PDF (23/35 Pages) Melexis Microelectronic Systems – Triaxis® Position Sensor IC

MLX90365
Triaxis® Position Sensor IC
14.6.1. Hysteresis Filter
The FHYST parameter is a hysteresis filter. The output value of the IC is not updated when the digital step
is smaller than the programmed FHYST parameter value. The output value is modified when the
increment is bigger than the hysteresis. The hysteresis filter reduces therefore the resolution to a level
compatible with the internal noise of the IC. The hysteresis must be programmed to a value close to the
noise level. ( 1 lsb = +/- 0.012%)
14.6.2. FIR Filters
The MLX90365 features 2 FIR filter modes controlled with Filter = 1…2. Filter = 0 corresponds to no
filtering. The transfer function is described below:
∑ ¹
y_n = _j
j
a_i x_n−i
∑ a i=0
i
i=0
The filters characteristic is given in the following table:
Filter No
J
Type
Coefficients ai
Title
99% Response Time
Efficiency RMS (dB)
0
0
Disable
1
No filter
1
0
1
2
1
3
Finite Impulse Response
11
1111
ExtraLight
Light
2
4
3.0
6.0
30000
20000
Digital value
[16bits]
10000
No filtering
FIR2 [1111]
FIR1 [11]
0
0
MLX90365
Rev. 5.7
10
20 Time [samples] 30
40
Figure 11 - Step and impulse response of the different filters
Page 23 of 35
50
Datasheet
Jan. 22, 16