X
X
L
L
D
D
C
C
M
M
A
A
N
N
.
.
d
d
o
o
c
c
1
1
-
-
6
6
R
R
E
E
V
V
E
E
Connector: Male 9-pin D subminiature.
Pin Assignment: See Section 1-60.
1-16 through 1-19 reserved
1-20 INPUTS AND OUTPUTS
A combination of up to five option input and output signals may be connected to the XL-DC via rear
panel mounted BNC connectors.
STANDARD OUTPUTS:
1-21 1 PPS OUTPUT (STANDARD)
A time-stable ACMOS levels 50 Ω 1 PPS output is connected to a rear panel BNC connector. The
rising edge of this pulse coincides with the start of the second. The pulse width is 20 µs. If no satellites
are being tracked, the 1 PPS pulse will be as stable as the internal (or external if so configured)
oscillator of the XL-DC. The 1 PPS output is capable of driving a 50 Ω load. This output is valid
whenever the XL-DC has an accurate position and is tracking at least one satellite.
Pulse width: 20 µs
On time edge: Rising
Amplitude: TTL Levels into 50 Ω
Drive: ACMOS
1-22 IRIG B OUTPUT (STANDARD)
An IRIG B Amplitude Modulated 1 kHz carrier output is connected to a rear panel BNC connector. The
primary purpose of the IRIG B time code output is to drive slave displays manufactured by TrueTime.
Refer to Section VIII for a full description of this code. When using this code for other than driving the
TrueTime Models RD-B, RMD-B, SF-DC or 560 Distribution Amplifier, it should be noted that four bits in
the "control functions" portion of the IRIG B code encode the TIME QUALITY INDICATORS. These are
fully described in Manual Section VIII.
The modulated 1 kHz sine wave is capable of driving a 600 Ω load. The high level of the code is
2.5 ±0.25 Vp-p and the low level is 0.75 ±0.1 Vp-p into 600 Ω. The open circuit levels are twice those
into 600 Ω, i.e. the source impedance is 600 Ω.
Time Code: Amplitude-Modulated IRIG B
Carrier: 1KHz
Amplitude: 5.0 Vp-p high, 1.5 Vp-p low, no load
Output Z: 600 Ω
1-23 through 1-29 reserved
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