For example: Agilent E4440A or Anritsu 68369
Willtek
Willtek is a telecommunications test and measurement equipment manufacturer. The company was founded in 1999 and specializes in providing test solutions for the wireless industry. Willtek's product portfolio includes handheld testers, spectrum analyzers, signal generators, and other equipment used for testing and troubleshooting wireless networks. In 2008, Willtek Communications was acquired by Aeroflex, a leading provider of test and measurement solutions for the aerospace, defense, and wireless industries. As a result of this acquisition, Willtek products became part of the Aeroflex product line.