The maser is a very stable frequency standard with two output signals, one at 100 MHz and one at 5 MHz. The 100 MHz output is the reference for the front end synthesizers (see Section 5.9) and the pulse cal system (see Sections 5.4 and 15.2). The 5 MHz output is the reference for the base band converters (see Section 5.13), the formatter (see Section 5.15), and the antenna timing.