Microsoft released emulators for Windows Phone 8 Update 2 and Update 3.
The update 3 emulator will help developers to test their applications in 1080p (1080 x 1920) resolution screen.
These emulator updates are optional downloads for Windows Phone developers,
They requires either
(a) Visual Studio 2012 Update 3 or (b) Visual Studio 2013 RTM, with the Windows Phone SDK 8.0 installed.
From the website
Installing a Windows Phone 8.0 Update 2 or 3 emulator set does not replace or update earlier instances of Windows Phone 8.0 emulator images that you might already have installed. This way you can keep multiple versions of the Windows Phone 8.0 operating system on your machine (if that’s how you roll). You can remove Windows Phone 8.0 emulator images from your machine at any time. In Control Panel, go to Programs and Features, and then uninstall the relevant emulator update.
Read more here