| ??? 11/17/05 10:54 Read: times |
#103848 - 50Hz sampling Responding to: ???'s previous message |
Something that caught me out once with FIRs: If you sample at precise 50Hz in order to cancel mains hum, the mains varies +/-1Hz (sometimes worse). You end up with a 'beat' signal of 0-1Hz on the output! This is virtually impossible to get rid of.
I actually changed to sampling rate of 60Hz - beat was now 9-11Hz - further filtering could now tackle this. Ultimately forgot FIRs and moved to IIRs, sampling at 50Hz, which removed the effect. And saved me copious RAM... Not so effective though. (For the US and Far East, swap 50 and 60 in the above text...) Dave |
| Topic | Author | Date |
| Weight Scale Avarging method | 01/01/70 00:00 | |
| Filter providing two time constants | 01/01/70 00:00 | |
| median filter, simulate algo on PC | 01/01/70 00:00 | |
| Periodic interference can make them fail | 01/01/70 00:00 | |
| Acknowlegded. | 01/01/70 00:00 | |
| Agreed | 01/01/70 00:00 | |
| 50Hz sampling | 01/01/70 00:00 | |
| Anti-aliasing filter will help | 01/01/70 00:00 | |
| what this is all about | 01/01/70 00:00 | |
| Moving average window. | 01/01/70 00:00 | |
| Average on condition | 01/01/70 00:00 | |
| is that not SOP (standard operating proc | 01/01/70 00:00 | |
| Hallelujah! | 01/01/70 00:00 | |
| meaningless | 01/01/70 00:00 | |
| What are you using that one for in a wei | 01/01/70 00:00 | |
hello from chhatraliamd for weight scale | 01/01/70 00:00 |