Fiber Optic Input Behavior; Auto-Switching - Symmetricom ATS-6511A User Manual

Done.
4399A BPSK File Format:
The BPSK file is sent to the 4399A unit through the serial port, via XMODEM. The file to be
sent must be in binary format, with the first 32 bits designating the full length of the file. The
BPSK signal may then begin on the 33
the BPSK file for a 10,000,000-chip pattern will actually be 10,000,032 bits long, and therefore
the first 32 bits of the file must read 009896A0 (when viewed with a hex editor).
This device is designed to utilize chip patterns in 1,000,000-chip increments in size, but can
accommodate any chip size that is divisible by 16. Maximum capacity of the internal flash
memory is 32 megabits. When sending an output, the 4399A will continuously repeat the entire
bit pattern in sequential order, from bit 33 to the end. Using this format, "1" represents the carrier
signal and "0" represents the carrier signal after a 180 degree phase shift.
A very short sample of a 64-bit BPSK pattern follows:
00000060 D1CAEF91 3134E17C
This will cause the unit to continuously repeat the following pattern:
1101 0001 1100 1010 1110 1111 1001 0001 0011 0001 0011 0100 1110 0001 0111 1100
2.5

Fiber Optic Input Behavior

The ATS-6511 does not have a front panel switch to select the desired Fiber Input. This is
accomplished via the auto switching feature or the command port. The default setting has Input
A as the primary input, the Auto-Switching feature enabled, the minimum time for the primary
source to be valid is 60 seconds, and the rearm feature is on. Once the ATS-6501s are operating
and their outputs are enabled they will send the reference signals via fiber to the ATS-6511(s).
One ATS-6501 drives Input A, a redundant ATS-6501 drives Input B. The ATS-6511 will select
Input A once that fiber pair comes on line and the system locks to it since it is the default input.
Once the ATS-6511 is operating and both fiber inputs are present the unit will monitor the fiber
inputs. The fiber pair driving the ATS-6511 is displayed on the front panel; Input A or Input B
will be ON and Green. The status input:switch command will indicate the switching mode and
the selected fiber pair. (i.e. Auto Switch: A). The alternate source input will also indicate the
status of the fiber and if the signal is present and it will flash Green (On for 1 second, off for three
seconds). If neither fiber input is available, the ATS-6511B or C will enter holdover mode using
the internal Rubidium (ATS-6511B-FR or ATS-6511C-FR option) if available, the external
reference input if available (ATS-6511B or C), or the internal OCXO (ATS-6511A, B or C).

2.5.1 Auto-Switching

When enabled, one of the two fiber pairs (A or B) will be the primary source. System settings
can be checked using the settings fiber:switching command.
ATS-6511>settings fiber:switching
rd
bit and continue to the end of the file. This means that
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DOC 6511_Release K
ATS-6511A/B/C Users Guide