Frequency Interpolator - Page 1
Forum section: electronics / projects

author: 0xFFF0
author_rank: Regular Contributor
timestamp: November 14, 2022, 03:58:58 pm
content: Is there a nice simple diy circuit (MCU?) to measure frequencies with an interpolator for finest resolutions?

author: Terry Bites
author_rank: Super Contributor
timestamp: November 14, 2022, 04:24:01 pm
content: Like a vernier?Use your input pulses to gate a higher frequency (precision) oscillator.www.instructables.com/High-Resolution-Frequency-Counter/

author: hgl
author_rank: Regular Contributor
timestamp: November 14, 2022, 05:51:16 pm
content: For hobby applications the simplest is to use a TDC7201 and a microcontroller. With this a resolution of RMS 60ps is possible. Search this forum and visit the (German) site :http://www.mino-elektronik.de/for schematics.

author: 0xFFF0
author_rank: Regular Contributor
timestamp: November 15, 2022, 09:42:30 am
content: The chip is quite interesting but hard to source.

author: Terry Bites
author_rank: Super Contributor
timestamp: November 15, 2022, 04:06:39 pm
content: what frequncies Hz, MHz, GHz?? Idle curiosity Hz?You might want to consider a low jitter clock mutiplier (digital PLL).

author: Picuino
author_rank: Super Contributor
timestamp: November 15, 2022, 04:32:25 pm
content: What is the application where you want to use the frequency meter?And what minimum resolution do you need?Another solution to the vernier is to use a CTMU module of a PIC microcontroller. It is a module that charges a capacitor with a constant current for very small time intervals. By measuring the capacitor voltage with the ADC, the size of the time interval can be known. It can measure intervals with a resolution of 200ps.

author: 0xFFF0
author_rank: Regular Contributor
timestamp: November 15, 2022, 05:55:11 pm
content: Isn't that all done by the 7200 chip?

author: hgl
author_rank: Regular Contributor
timestamp: November 15, 2022, 06:14:42 pm
content: Quote from: 0xFFF0 on November 15, 2022, 09:42:30 amhttps://www.mouser.de/c/?series=TDC72011925 in stock 4,17 € each.

author: mino-fm
author_rank: Regular Contributor
timestamp: November 15, 2022, 08:15:02 pm
content: Without TDC:https://www.eevblog.com/forum/projects/8-11-digits-reciprocal-frequency-counter-0-1-hz-150-mhz/msg3386880/#msg3386880(PCB available, G431:https://lcsc.com/product-detail/Microcontroller-Units-MCUs-MPUs-SOCs_STMicroelectronics-STM32G431KBT6_C529357.html)or reduced functions a little bit cheaper by using RP2040 picoboard (coming at end of 2022-11).Or you use AS6501 in LQFP48:https://www.mouser.de/ProductDetail/ScioSense/AS6501-FLQM?qs=%252BEew9%252B0nqrAbCpBiX0DUew%3D%3DAttention: TDCs need some extra logic to synchronize start-stop-signals.

author: 0xFFF0
author_rank: Regular Contributor
timestamp: November 16, 2022, 09:21:34 am
content: Pretty impressive project. But that's beyond my capabilities at the moment.

author: mino-fm
author_rank: Regular Contributor
timestamp: November 16, 2022, 09:36:19 am
content: You'd better tell us what do you want.Quote from: Terry Bites on November 15, 2022, 04:06:39 pm

author: MegaVolt
author_rank: Frequent Contributor
timestamp: November 16, 2022, 09:56:10 am
content: You can get the idea here:https://www.eevblog.com/forum/projects/diy-interpolating-frequency-counter-fc-510/