Guru
Joined: 09/06/2017
Location: FinlandPosts: 330
| Posted: 06:01pm 07 Dec 2022 |
Made new shielded connections and measured the performance of the PIO frequency meter again. With 2MHz input (now confirmed by oscilloscope) the measured value is on average 296Hz too low and the standard deviation 29Hz.
The error increases with increasing frequency.
At 4MHz it is about 370Hz too low with a sd of about 120Hz.
At 500kHz the measuement is about 1Hz too high with a sd of about 1.5Hz.
The measurements were averaging 100000 measurements (ca 6s per mesurement).