Relation of Sampling Rate to Tracking Rate

[garimella]

Referring to AN3943. I have the following questions

1. How to convert the position information to digital. Will this conversion lead to truncation errors?

2. Does tracking rate depend on the sampling frequency. For eg For a 12 bit RDC, rollover takes place at 4095 counts/sec for 1 RPS. This means every LSB changes 244us. Could this mean that to detect this change in ATO sampling rate should be atleat 240us or 4Khz?

[davidtosenovjan]

Hi, which device is this question related to?

[garimella]

Referring to AN1942, device 56F80X. I am presuming that sampling frequency should be fast enough to detect the smallest change in the rotor speed. For a 12 bit RDC, speed updation rate is 244us for 60 rpm ( 1rps/4095). Similarly for 10 rps, updation rate would be 24.4us. Here sampling rate must be better that 24 us ( say 20us or 50KHz) to ensure that every delta changes are tracked correctly. Can you clarify if this is true?