The economical rack-mount XL-AK GPS receiver provides ultra-precise time and frequency. This configurable instrument provides timing outputs to within 40 nanoseconds rms of UTC/USNO and frequency outputs accurate to less than 1x10-12, even when tracking satellites with Selective Availability (SA) implemented. User-configurable outputs provide significant flexibility in configuring the XL-AK as a central source for IRIG time codes or output pulses.The XL-AK is a popular and affordable GPS receiver for general timing as well as specific power utility and range timing applications. The unit is well suited for precise time and frequency outputs to sequence-of-event recorders (SERs), fault locators, and voltage phase angle systems, as well as frequency and time measurement. The time code output lends itself well for range time distribution and data acquisition applications.Standard outputs include a 1 PPS, analog IRIG B time code and serial I/O time strings. Using the keypad or RS-232 port, users have control over a variety of time formats, configurations, and output options, including GPS and oscillator status and controls. For applications requiring increased oscillator stability, the XL-AK can be upgraded to higher performance oscillators.The five user configurable rear panel BNC connectors offer the utmost in value and flexibility. Each output can be configured with either an analog or digital driver. Each driver array has the following input signals available to it:IRIG B, E and H (DC level shift)IRIG B (amplitude modulated)