Following the trend of the era that wants everything to be HD, NES... could not miss the process.
The kit is available from here ($ 120) and does not only fix the quality, but it also has some other features. Note that something similar is also being prepared for the N64. The kits use NES' CPU and PPU and it's not like a clone of the console. The kit, although simple to install, requires you to desolder the CPU, so you should have the proper knowledge before doing it.
The signal do not has noise, since there is no analog signal conversion. It has automatic detection for PAL/NTSC, so if you buy it and have a PAL machine, it will not be a problem.
The resolutions are: NTSC video modes: 480p, 720p, 1080p 60fps (NTSC CPU/PPU only) PAL video modes: 576p, 720p, 1080p 50fps (PAL CPU/PPU only) Various picture and color palette options. It has a choice of button combinations to make Reser, Over/Under clock from distance. Upgrade capability and other options you can see on the page mentioned above.
See more in the video below