| ??? 07/22/09 10:38 Read: times |
#167683 - Frequency Counter using prescaler |
Hi all
I would like to build a frequency counter that can count to RF frequencies (2.5GHz). doing a search on the internet I found a lot of information on PICs using prescalers (divide by 64 / 128 etc) this is all fine however the description of how they work is not particularly clear and I was wondering if some one could enlighten me. 1. If I divide the RF frequency by 128. how does this not give me an error of 128x the counted value. 2. How do they work. 3. how do they get the resolution. 4. I'm interested in resolution to a few hundred kHz. Ideally I would like to feed the count into an LPC9xx counter input I am happy enough to code it up, I just need a couple of pointers in the right direction. Thanks and Regards Marshall Brown |
| Topic | Author | Date |
| Frequency Counter using prescaler | 01/01/70 00:00 | |
| Find prescaler. Then find time period. Then multiply count. | 01/01/70 00:00 | |
| Think about crystal stability | 01/01/70 00:00 | |
| Oscillator candidate | 01/01/70 00:00 | |
| i wish that would become clear to the majority | 01/01/70 00:00 | |
| 0.1 % | 01/01/70 00:00 | |
| I'm sorry? | 01/01/70 00:00 | |
| i'm sorry | 01/01/70 00:00 | |
| Clearer now | 01/01/70 00:00 | |
| Dividers increase the error, but... | 01/01/70 00:00 | |
| if extreme precision is required ... | 01/01/70 00:00 | |
| or count more seconds | 01/01/70 00:00 | |
| Remember resolution != precision :) | 01/01/70 00:00 | |
Excellent - responses thanks so much | 01/01/70 00:00 |