Low cost...Easy to build...Highly accurate...An essential piece of test equipment! ∞ARDUINO-BASED DIGITAL AUDIO MILLIVOLTMETER

摘要

We decided to design a new audio millivoltmeter because we wanted one which worked over a very wide range of signal amplitudes with excellent accuracy and resolution.We also wanted to provide the ability to measure balanced or unbalanced audio signals without the need for any additional hardware.But most of all,we wanted it to be easy to build and would fit in a compact case.So why build this one instead of our previous audio millivoltmeter(March 2009-siliconchip.com.au/article/13721? For many reasons,this new unit makes that old one obsolete: 1.It can measure smaller signals and much larger signals.2.It has much better resolution.3.Its frequency response(on both ranges)is much better(see Fig.l).4.It has a built-in balanced input(no separate converter required).5.It does not require manual range selection 6.It runs off USB power.7.It is quite a bit smaller.Some of the improvements in this version are due to our use of an Arduino Nano MCU module for control,while most of the performance improvements are due to our use of an LTC2400 24-bit analog-to-digital converter(ADC).