© 2006 Jackson-Labs
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FireFox Synthesizer User Manual
3.3.8 What happens to the FireFox settings when the power is
turned off?
The FireFox units have non-volatile memory that stores settings such as the frequency, amplitude,
and menu options. This non-volatile memory does not require any battery backup. The unit will thus
power-up with the last frequency and amplitude setting used prior to power-down.
Several important settings are stored in the GPS receiver and are backed up by a rechargeable battery
that has a life span of typically several days when the unit is powered off. These settings are the
position established by the Auto-Survey function and used for position-hold mode, the time offset
from GMT, and the receiver operating-mode.
3.3.9 How accurate is the output power on the RF output
connector?
The FireFox units offer two output modes on the RF BNC connectors, relative and absolute output
mode. The operating mode is selected in the “SETUP” menu. Relative mode allows controlling the
output power from 0% to 100% of the units’ capability, with the actual output power level varying
with the frequency. This mode allows the user to harvest the maximum possible output power the unit
can generate at any given frequency. Maximum power levels in relative mode typically range from
+8dBm to +18dBm depending on the output frequency.
Absolute mode is used when highly accurate power levels are required. Absolute mode sets the
output power to factory-calibrated levels ranging from -40dBm to +10dBm. The output power at the
RF BNC connector is accurate to -1dBm of the value displayed in the LCD over the units’
frequency range (+-0.2dbm typical accuracy).
3.4 Hardware FAQs
These FAQs describe the hardware implementation and connectivity requirements of the FireFox
Signal Generators.
3.4.1 The rear panel says: “Do not terminate CMOS outputs”.
Can the outputs drive 50 Ohm end-terminated cables?
The FireFox uses high speed, strong CMOS drivers to drive the rear 1PPS output, the 10MHz output,
and the front CMOS output. These outputs are designed to drive unterminated (open-ended) 50 Ohm
cables as well as 50 Ohm end-terminated cables. The outputs can drive a minimum of +24mA. Using
unterminated cables yields 3.3V logic levels, while using 50 Ohm end-terminators will reduce the
output amplitude by ca. 50% making them non TTL compatible; thus the warning label.
The CMOS output drivers used in the FireFox provide both very low jitter and a very small 1PPS
delay (in the order of a couple of nanoseconds). They can drive both AC coupled, sine-wave 50 Ohm
inputs as well as digital TTL/CMOS inputs and thus provide more flexibility than traditional
sine-wave outputs.
Summary of Contents for FireFox
Page 1: ...FireFox Synthesizer User Manual Document 0012008 Version 004 Date 10 April 2008...
Page 2: ...FireFox Synthesizer User Manual Copyright 2008 Jackson Labs...
Page 34: ...FireFox Synthesizer User Manual 28 2006 Jackson Labs...
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