Code out, Alarm, Code out alarm – Symmetricom XL-GPS User Manual

Page 17: Time and frequency accuracy” on page 3

997-01530-01, Rev. C-25, Jan 2008

Code Out

The default output is IRIG-B-120 AM. Configuration is via the Keypad, Serial I/O, and Network port.

Five flags are encoded in the control function segment of the IRIG B code. The first flag encoded at
element P5+40ms is the LOCK indicator. It is a binary 1 when the reference source has become
unlocked. The second flag encoded at element P5+60ms is a binary 1 when the worst case time error
exceeds threshold 1 element P5+70ms is a binary 1 when the worst case time error exceeds threshold
2. Element P5+80ms encodes a binary 1 when the error exceeds threshold 3 and P5+90ms when the
error exceeds threshold 4.

The time code resets as follows:

Alarm

The open collector alarm output has the following states:

Format:

IRIG B-120 1 kHz AM -000 DC

Amplitude (AM):

3 Vp-p, into 50

Ω +/-10%

Ratio (AM):

3:1 +/-10%

Amplitude (DC):

TTL into 50

Qty:

Connector:

BNC female

Phasing:

In phase with carrier ± 10

μS

Accuracy:

Refer to

“Time and Frequency Accuracy” on page 3

Days Reset:

Resets to day 1 after day 365

Leap Year:

Resets to day 1 after day 366

Drive:

Open Collector

Max. Voltage:

25 VDC

Max. Current:

50 mA

Qty:

Connector:

BNC female

Off

(High Z) Power off

Off

(High Z) Error, major or minor enabled alarm fault.

(Low Z) Normal, no major or minor enabled alarm faults.