PNI RM3000 Sensor Suites - Manual (Page 9)

RM3000 & RM2000 Sensor Suite User Manual r08 Page 9 of 41
3.4 Typical Sensor Suite Operating Performance
Figure 3-1 plots typical gain-determined resolution as a function of the single axis sample
rate. The plot starts at 300 Hz since the usable resolution is limited by best-case system noise
of ~15 nT. The plot stops at 2400 Hz because this represents a cycle count of ~30, and
operating at cycle counts much lower than this introduces significant quantization error.
(The number of cycle counts is determined by the user, as explained in Sections 5.1 and 6.2.)
Figure 3-1: Sample Rate vs. Resolution – Standard Mode
(Usable resolution will be limited by system noise at lower sample rates)
The plots below are representative of performance as a function of the number of cycle
counts, which is a parameter directly controlled by the user. The first two plots show
performance for operation in both Standard Mode and the default Legacy Mode out to 10,000
cycle counts. The maximum number of cycle counts in Legacy Mode is 4096. In Standard
Mode the maximum cycle counts is 65.5k, but there’s rarely a reason to operate in Standard
Mode much beyond 200 cycle counts, as discussed in the following paragraph.
Figure 3-4, Figure 3-5, and Figure 3-6 show performance when operating in Standard Mode
out to 200 cycle counts. Operation in Standard Mode at more than 200 cycle counts usually
is inefficient since more time and power is consumed per measurement, with diminishing
returns in usable (noise-limited) resolution.
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Single-Axis Sample Rate (Hz)