swake 0 Report post Posted February 28, 2019 Hello, is it possible to mesure vidéo signal composite with DSO Nano osciloscope ? Quote Share this post Link to post Share on other sites
Mr.RC-Cam 127 Report post Posted February 28, 2019 Its bandwidth is too low for accurate measurements. Quote Share this post Link to post Share on other sites
swake 0 Report post Posted February 28, 2019 What bandwidth value does it need? Which model do you recommend ? Quote Share this post Link to post Share on other sites
Mr.RC-Cam 127 Report post Posted February 28, 2019 For accurate measurements you need an oscilloscope with an analog bandwidth at least five times the measured signal bandwidth. NTSC and PAL video is about 5MHz, so the scope should be rated for 25MHz or higher bandwidth. I use a TEK2445 analog scope that is 100MHz with TV Sync capabilities. But I've done it with a cheap digital scope that had about 1MHz bandwidth. The results were suitable for crude video signal level calibration.https://www.rc-cam.com/forum/index.php?/topic/2825-using-the-50-digital-scope-to-measure-video-levels/ If your main goal is to calibrate FPV composite video, then there is a low cost ($20 USD) DiY solution that is very accurate.https://www.rc-cam.com/forum/index.php?/topic/4126-diy-fpv-video-calibration-tool-low-cost/ Quote Share this post Link to post Share on other sites
swake 0 Report post Posted March 1, 2019 DSO NANO V3 - analog 200Khz de la bande passante. How can you measure a video signal with a bandwidth of 5Mhz if your Osciloscope stops at 1Mhz? Quote Share this post Link to post Share on other sites
Mr.RC-Cam 127 Report post Posted March 1, 2019 Most of the details to the video signal are lost with a 1MHz scope. But in my experiment, the bottom of V-Sync and peak white amplitude were present, so a crude measurement was possible. Don't purposely purchase a cheap digital scope if you intend to do video measurements. But if you already own it, then try this: First use it to observe a good (calibrated) NTSC or PAL video signal. If the 1Vpp amplitude measurement appears valid then you will have confidence that it can be used to measure/calibrate a bad video signal. Quote Share this post Link to post Share on other sites
