Jackson Labs LC_XO, Manual

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LC_XO GPSDO User Manual
8 © 2012 Jackson Labs Technologies, Inc.
2.2 Using a Socket
The LC_XO board may either be soldered onto a PCB or it can be inserted into a socket on the users’
PCB for optional retrofitting of customer products. The pins used on the LC_XO board are
manufactured by Samtec and have part number BBL-115-G-E. The board may be inserted into a
Samtec mating low profile socket strip of the SL series, or similar products.
2.3 Operating with GPS
Please make sure to connect the GPS antenna prior to connecting power to the unit.
Caution: use a Lightning Arrestor on your Antenna setup.
The LC_XO board GPS receiver includes a 50 channel high-sensitivity GPS receiver with very fast
lock time. It does not require any self-survey or position-hold mode (auto survey), and thus can be
used in mobile platforms.
The LC_XO board is capable of generating standard navigation messages on the SCPI serial port (see
GPS:GPGGA and GPS:GPRMC serial commands) that are compatible with most GPS based
navigation software. Please note that the LC_XO board indicates MSL height (rather than GPS
height) in its GPGGA, GPS? and syst:stat? output strings. The LC_XO also provides raw NMEA and
uBlox binary output strings on pin 12 for additional information.
The internal GPS receiver generates a 1PPS time signal that is phase synchronized to UTC. This
1PPS signal is used to frequency-lock the 10MHz output of the LC_XO board to UTC, thus
disciplining the unit’s 10MHz frequency output to the US Naval master clock for very high
frequency accuracy (typically better than 1ppb of frequency accuracy when locked to GPS). Over the
long term, the LC_XO board will out-perform free-running Cesium Atomic Frequency Standards.
2.4 Remote serial control
•
The unit is controlled via the ttl level serial port at 115200 baud, 8N1. Other Baud Rates can be set
via SCPI commands over the serial port.
•
WARNING: DO NOT CONNECT THE TTL LEVEL SERIAL PORT TO AN RS-232
LEVEL SERIAL INTERFACE, THIS WILL DAMAGE THE UNIT.
•
Attach the LC_XO board to your PC’s Hyperterminal, the Z38xx software available on the
Jackson Labs Technologies, Inc. website, or the optional GPSCon software package. Configure the
application software for 115200 Baud, 8 bits, no parity, 1 stop bit, and no flow control where
applicable.
14 RX In SCPI RX Input 3.3V SCPI serial interface
input, 5V compatible
15 TX Out SCPI/NMEA
Output 3.3V serial output