Time-to-digital converters (TDCs) measure short time intervals with great precision. They are widely used in ranging devices, in positron emission tomography (PET) medical scanners, and in automated test equipment. A new, faster TDC with better precision measures time intervals at a resolution of up to 10 ps with a sampling rate of up to 70 MHz.

Any frequency meter is only as accurate as its timebase. Unfortunately, a high-precision timebase is expensive which is why many commercial frequency meters a.k.a. counters use quartz crystal standards for this important task. Some of these meters have an external 10 MHz reference input that can be used to improve their precision. All you have to do is to devise and connect a high-precision 10 MHz signal and away you go. But how do you calibrate your high-precision reference? Errm…

This time we take a closer look not only at the software that makes it all work, but also at the maths that made this tool possible in the first place. We will first look at the software of both the microprocessor and the PC. Little by little some mathematical principles will be introduced to transform you in a digital signal processing expert.

Elektor's clock galary / museum. Which clock to you like most?  Sputnik Time Machine.

For sure: this is not a very original project: countless people designed a clock. Why another one? Well, this is a very compact clock built with 4 nixie tubes. It fits in a small box (17 x 9 cm) and the time is acquired with a GPS module, so no adjustment is needed. If there is any interest I will write a projectdescription.Buy the PCB and programmed controller in the Elektor shop:

A little circuit to try out the built-in I²C driver of the LPC810. Thanks to the Switch Matrix the I²C interface can be connected to the few available pins of the LPC800 Mini Kit board. The I²C driver is used in polling mode.

           The extreme accuracy! Definitely it is a feature of Maxim DS3231, a extremely accurate I2C real time clock (RTC) with integrated temperature compensated crystal oscillator (TCXO) and crystal.

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Buy it here!A propeller clock, also known as a Persistance Of Vision (POV) display is based on a mechanically moving led row. This led row is either oscillating or rotating at a rate superior to human's eye remanence, making a dot matrix which seems to float in the air.

Published in the October 2013 Edition PLEASE NOTE:- In some editions fo the Magazine (GB, DE), the Temprature sensor is listed as a DS1820 - This should read DS18B20. The DS1820 is an old part and does not function correctly in this project.