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XLi Time & Frequency System
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XLi-man, Issue 8, 6/17/2008, Rev. H
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Have Quick Input Specifications
Have Quick Signal Characteristics
The Have Quick signal employs bi-phase (Manchester II) transmission at approximately 1667 bits per
second. A one is defined as 300 microseconds of a low state followed by 300 microseconds of a high
state. A transmission of 240 milliseconds of logic ones (400 bits) precedes the start of message indicator
(16 bits) and time, day of year, year and TFOM message (96 bits).
The transmission is initiated on a time mark, so that the first bit of the 400 “ones” starts within 10
microseconds of the leading edge of the 1PPS.
The start of message indicator that follows the “ones” verifies that the time, day of year, year and TFOM
message will follow. Each 8 bit character in the data message (time of day, day of year, year and TFOM)
is defined by a modified 8:4 Hamming Code. The two start of message characters (8 bits each) are not in
the modified Hamming Code.
The modified Hamming code employs 4 parity bits and 4 data bits for each 8 bit character.
2 x 10
-10
@ 1000 sec
3 x 10
-12
@ 1 day
High Level:
Logic Hi > 1.25V < 10V
Low Level:
Logic Low < 1.25V > 0V
Synchronization edge:
Positive
Impedance:
1 k
Ω
to ground
Qty:
1
Connector:
BNC female
Accuracy:
1
μ
S
Stability:
1 x 10
-9
@ 1 sec
2 x 10
-10
@ 1000 sec
3 x 10
-12
@ 1 day
High Level:
Logic Hi >4.5V and Max. 5.5V
Low Level:
Logic Low <+0.5V and Min. 0V
Impedance:
1k
Ω
to ground
Qty:
1
Connector:
BNC female
CPU Aware
Yes
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