Jackson Labs FireFox User manual

FireFox Synthesizer
User Manual
Document: 0012008
Version: 004
Date: 10 April, 2008

FireFox Synthesizer User Manual
Copyright © 2008 Jackson-Labs

© 2006 Jackson-Labs i
FireFox Synthesizer User Manual
Table of Contents
1Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 Limitation of Warranty . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.3 Exclusive Remedies . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.4 Safety Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3.1 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . 3
1.3.2 Line Power and Grounding . . . . . . . . . . . . . . . . . . . . . . 3
1.3.3 Line Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3.4 Do not operate the Instrument in an Explosive Atmosphere . . . . . . . . . 3
1.3.5 Keep away from Live Circuits . . . . . . . . . . . . . . . . . . . . . 3
1.3.6 Do not Service or Adjust alone . . . . . . . . . . . . . . . . . . . . 4
1.3.7 Do not exceed Ratings . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.8 Do not substitute parts or modify the Instrument . . . . . . . . . . . . . 4
1.3.9 Operational Warning . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4 Quick Start Instructions . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.1 Connecting the instrument . . . . . . . . . . . . . . . . . . . . . . 5
1.4.2 Initializing the GPS . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.3 Setting up the GPS . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4.3.1 GPS Time Offset . . . . . . . . . . . . . . . . . . . . . . 6
1.4.3.2 Selecting Metric/US Mode . . . . . . . . . . . . . . . . . . . 6
1.4.3.3 GPS Auto Survey . . . . . . . . . . . . . . . . . . . . . . 6
1.4.4 Setting the Frequency. . . . . . . . . . . . . . . . . . . . . . . . 6
1.4.5 Setting the RF Amplitude . . . . . . . . . . . . . . . . . . . . . . 7
1.4.6 Using the CMOS and LVDS outputs . . . . . . . . . . . . . . . . . . 8
1.4.6.1 Connecting a cable to the LVDS Outputs . . . . . . . . . . . . . 8
1.4.6.2 Connecting a cable to the CMOS Output . . . . . . . . . . . . . 8
1.4.6.3 Selecting the Front Panel CMOS Output Voltage . . . . . . . . . . 8
1.4.7 Setting up the DDS . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.4.7.1 Setting the Phase Offset . . . . . . . . . . . . . . . . . . . 9
1.4.7.2 Mixer ON/OFF . . . . . . . . . . . . . . . . . . . . . . . 9
1.4.7.3 FRACT ON/OFF . . . . . . . . . . . . . . . . . . . . . . 9
1.4.7.4 Noise/Spur Optimization . . . . . . . . . . . . . . . . . . . 9
1.4.8 Setting up the Output . . . . . . . . . . . . . . . . . . . . . . . . 9
1.4.8.1 Frequency Limit . . . . . . . . . . . . . . . . . . . . . . . 9
1.4.8.2 Power Unit . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.4.8.3 Power Limit . . . . . . . . . . . . . . . . . . . . . . . . 10
1.4.9 Setting up Frequency Sweeps . . . . . . . . . . . . . . . . . . . . 10
1.4.10Monitoring the Instrument Status . . . . . . . . . . . . . . . . . . . 11

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1.4.10.1OCXO Status . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.10.2GPS Status . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.10.3Sys Config . . . . . . . . . . . . . . . . . . . . . . . . 12
1.4.11Using the External Mixer . . . . . . . . . . . . . . . . . . . . . . 12
1.4.12Storing and Recalling Setups . . . . . . . . . . . . . . . . . . . . 13
1.4.13Using the GPS and OCXO Reference Outputs. . . . . . . . . . . . . . 13
1.4.13.1GPS Receiver 1PPS Output. . . . . . . . . . . . . . . . . . 13
1.4.13.2OCXO Timing Reference Output . . . . . . . . . . . . . . . . 14
1.4.14Advanced GPS Setup . . . . . . . . . . . . . . . . . . . . . . . 14
1.4.14.1Factory Reset . . . . . . . . . . . . . . . . . . . . . . . 14
1.4.14.2GPS TRAIM Filter. . . . . . . . . . . . . . . . . . . . . . 14
1.4.14.3Controlling the M12+ GPS Receiver using a PC . . . . . . . . . . 15
1.4.15Entering the Calibration Mode . . . . . . . . . . . . . . . . . . . . 15
1.4.16Entering SCPI Remote Control Mode . . . . . . . . . . . . . . . . . 15
1.5 FireFox Desktop Typical Specifications . . . . . . . . . . . . . . . . . . . 16
1.5.1 Specification Summary . . . . . . . . . . . . . . . . . . . . . . . 16
1.5.2 Typical Allan Deviation Plots . . . . . . . . . . . . . . . . . . . . . 18
1.5.3 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.6 Detailed Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.6.1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.6.2 Signal Generator Outputs . . . . . . . . . . . . . . . . . . . . . . 22
1.6.3 GPS Disciplined OCXO Reference . . . . . . . . . . . . . . . . . . 23
1.6.4 DDS Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.6.5 RF Output Buffer . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.6.6 User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.6.7 NV-memory . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.6.8 Frequency Sweeping. . . . . . . . . . . . . . . . . . . . . . . . 25
1.6.9 Differences between Desktop unit and OEM module . . . . . . . . . . . 25
1.6.10Generic Mixer . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2 SCPI Remote Control . . . . . . . . . . . . . . . . . . . . . . . 29
2.1 RS-232 SCPI Remote Control . . . . . . . . . . . . . . . . . . . . . . 29
2.2 SCPI Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.3 Initiating SCPI Control Mode . . . . . . . . . . . . . . . . . . . . . . . 29
2.4 Serial Communication Setup . . . . . . . . . . . . . . . . . . . . . . . 30
2.5 Support for IEEE488.2 Mandated Commands . . . . . . . . . . . . . . . . 30
2.5.1 Frequency Subsystem . . . . . . . . . . . . . . . . . . . . . . . 31
2.5.1.1 [SOURce]:FREQuency. . . . . . . . . . . . . . . . . . . . 31
[SOURce]:FREQuency:CW 31
[SOURce]:FREQuency:MODE 31
[SOURce]:FREQuency:CENTer <numeric_value> 31
[SOURce]:FREQuency:SPAN <numeric_value> 32
[SOURce]:FREQuency:STARt <numeric_value> 32
[SOURce]:FREQuency:STOP <numeric_value> 32
2.5.2 Sweep subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 32
2.5.2.1 [SOURce]:SWEep . . . . . . . . . . . . . . . . . . . . . 32
2.5.2.2 [SOURce]:SWEep:MODE <HW | SW> . . . . . . . . . . . . . 33
2.5.2.3 [SOURce]:SWEep:DWELl <numeric value> . . . . . . . . . . . 33
2.5.2.4 [SOURce]:SWEep:POINTs <numeric value> . . . . . . . . . . . 34
2.5.2.5 [SOURce]:SWEep:TIME <numeric value | AUTO> . . . . . . . . . 34

© 2006 Jackson-Labs iii
FireFox Synthesizer User Manual
2.5.2.6 [SOURce]:SWEep:STEP? . . . . . . . . . . . . . . . . . . . 34
2.5.2.7 [SOURce]:SWEep:GENeration < ANALog | STEPped > . . . . . . . 34
2.5.2.8 [SOURce]:SWEep:SPACing <LINear | LOGarithmic> . . . . . . . .35
2.5.2.9 [SOURce]:SWEep:DIRection <UP | DOWN| UPDOWN> . . . . . . .35
2.5.2.10[SOURce]:SWEep:COUNt <numeric value> . . . . . . . . . . .35
2.5.2.11Software-Controlled Sweep configuration example . . . . . . . . . 35
2.5.2.12Hardware-Controlled Sweep configuration example . . . . . . . . . 36
2.5.3 Power Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.5.3.1 [SOURce]:POWer[:LEVel] [IMMEdiate][:AMPLitude] <numeric_value> . 37
2.5.4 Phase Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 37
2.5.4.1 [SOURce]:PHASe[:ADJUST] <numeric_value> <unit> . . . . . . .37
2.5.5 Output Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 37
2.5.5.1 OUTPut[:STATe] <ON | OFF> . . . . . . . . . . . . . . . . 37
2.5.6 Initiate Subsystem . . . . . . . . . . . . . . . . . . . . . . . . .37
2.5.6.1 INITiate: . . . . . . . . . . . . . . . . . . . . . . . . . .37
2.5.7 Measure Subsystem . . . . . . . . . . . . . . . . . . . . . . . . 38
2.5.7.1 MEASure:TEMPerature . . . . . . . . . . . . . . . . . . . .38
2.5.8 System Subsystem . . . . . . . . . . . . . . . . . . . . . . . . .38
2.5.8.1 SYSTem:COMMunicate:SERial. . . . . . . . . . . . . . . . .38
SYSTem:COMMunicate:SERial:BAUD<numeric_value> 38
SYSTem:COMMunicate:SERial:ECHO ON|OFF 38
2.5.9 Miscellaneous proprietary commands . . . . . . . . . . . . . . . . . 39
2.5.9.1 HELP? . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.5.9.2 SOURCE? . . . . . . . . . . . . . . . . . . . . . . . . .39
2.6 SCPI Command Examples . . . . . . . . . . . . . . . . . . . . . . . . 39
2.6.1 Setting the FireFox into Continuous Wave Mode . . . . . . . . . . . . . 39
2.6.2 Configuration and Settings Query . . . . . . . . . . . . . . . . . . . 39
3FAQs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.2 General FAQs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.2.1 How can the FireFox Synthesizers offer such high performance for such a low price?41
3.2.2 How did you decide what features to include in the FireFox synthesizers? . . .41
3.2.3 How long does the FireFox system take to warm up? . . . . . . . . . . .42
3.2.4 Why is there no power switch on the FireFox? . . . . . . . . . . . . . . 42
3.3 Application/Usage FAQs . . . . . . . . . . . . . . . . . . . . . . . . . 42
3.3.1 What is the difference between the FireFox Desktop unit and the FireFox OEM PCB?42
3.3.2 What applications is the FireFox Synthesizer designed for? . . . . . . . . .42
3.3.3 Can the FireFox system keypad be locked? . . . . . . . . . . . . . . . 43
3.3.4 How come the Frequency Display doesn’t let me select the exact Frequency I need?43
3.3.5 How come the display shows “UNCAL” below 1Hz? . . . . . . . . . . . .44
3.3.6 What do the LED’s in the front panel indicate? . . . . . . . . . . . . . .44
3.3.7 What do I have to do to move the FireFox unit to a different location? . . . . .44
3.3.8 What happens to the FireFox settings when the power is turned off? . . . . . 45
3.3.9 How accurate is the output power on the RF output connector? . . . . . . .45
3.4 Hardware FAQs . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
3.4.1 The rear panel says: “Do not terminate CMOS outputs”. Can the outputs drive 50 Ohm end-ter-
minated cables?45
3.4.2 Can the FireFox system be powered by a battery? . . . . . . . . . . . . 46
3.4.3 What are the mixer connections on the front panel used for? . . . . . . . . 46
3.4.4 How can I calibrate the FireFox Signal Generator? . . . . . . . . . . . . 46

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3.5 GPS Receiver FAQs . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.5.1 Why did you include a GPS receiver in the FireFox synthesizers? . . . . . . 47
3.5.2 How does the FireFox handle GPS hold-over mode? . . . . . . . . . . . 48
3.5.3 Can the internal GPS receiver be connected to a PC? . . . . . . . . . . . 48
3.5.4 I can connect to the GPS receiver from my PC, but cannot change any settings? 48
3.5.5 What is the GPS Auto-Survey Mode? . . . . . . . . . . . . . . . . . 48
3.5.6 What is the T-RAIM mode in the GPS receiver? . . . . . . . . . . . . . 49
3.5.7 Why did you not use a cheap, standard GPS receiver? . . . . . . . . . . 49
3.5.8 What types of GPS antennae are supported? . . . . . . . . . . . . . . 49
3.5.9 What do the SAT and STAT items in the LCD display indicate? . . . . . . . 49
3.6 Performance FAQs . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.6.1 How does the FireFox Synthesizer offer such wide bandwidth? . . . . . . . 50
3.6.2 How can spur performance be increased even further? . . . . . . . . . . 50
3.6.3 Does the FireFox need calibration? . . . . . . . . . . . . . . . . . . 50
3.6.4 There is a Frequency Estimate display in the menus. What is this number? . . 50
3.6.5 There is a Resolution number displayed in the menus. What is this number? . . 51
3.6.6 There is an option to turn Fractional-N mode on/off. What is this used for? . . . 51
4 Auto Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.2 Power Meter Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.2.1 Updating the Agilent Sensor Cal Table . . . . . . . . . . . . . . . . . 53
4.2.2 Using alternate Power Sensors, Power Meters. . . . . . . . . . . . . . 53
4.2.3 Calibrating the Power Sensor . . . . . . . . . . . . . . . . . . . . 54
4.3 Calibration Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.3.1 Sensor Connection . . . . . . . . . . . . . . . . . . . . . . . . 55
4.3.2 Serial Cable Connection . . . . . . . . . . . . . . . . . . . . . . 56
4.4 Initiating Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . 57

© 2006 Jackson-Labs 1
FireFox Synthesizer User Manual
Introduction
1.1 Overview
The FireFox synthesizer is a continuous wave (CW), a digital, and a sweeping broadband signal
generator with an ultra high-accuracy built-in frequency reference. The unit can generate CW or
sweep signals ranging from 0.00001Hz to 1640MHz in 0.00001Hz steps.
It derives its frequency accuracy from an internal GPS receiver that feeds Cesium-quality (long term
stability) reference signals to the Synthesizer unit. The unit does not require maintenance as Cesium
oscillators do (Cesium references need expensive physics package replacements every 5 years or
less), and provides better long-term time-base accuracy than non GPS-disciplined Cesium
references.
This manual describes the FireFox GPS disciplined broadband synthesizer module and Desktop unit.
The FireFox GPS Disciplined broadband signal generator is available as a benchtop unit or
OEM-module. Both units use a built-in, highly stable GPS-disciplined Oven Controlled Crystal
Oscillator (GPSDO). The FireFox Synthesizer for the first time combines sine-wave and digital
outputs, and a highly stable frequency reference in one instrument. This combination can generate
digital CMOS and LVDS/PECL square waves, and analog RF sine-wave outputs from DC to
1.64GHz with better than 1E-012 long term frequency accuracy.

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2© 2006 Jackson-Labs
1.2 Certification
Jackson Labs certifies that this product met its published specifications at time of shipment.
1.2.1 Warranty
This Jackson Labs hardware product is warranted against defects in material and workmanship for a
period of 1 (one) year from date of delivery. During the warranty period Jackson Labs will, at its
discretion, either repair or replace products that prove to be defective. Jackson Labs does not warrant
that the operation for the software, firmware, or hardware shall be uninterrupted or error free even if
the product is operated within its specifications.
For warranty service, this product must be returned to Jackson Labs or a service facility designated
by Jackson Labs. Customer shall prepay shipping charges (and shall pay all duties and taxes) for
products returned to Jackson Labs for warranty service. Except for products returned to Customer
from another country, Jackson Labs shall pay for return of products to Customer. If Jackson Labs is
unable, within a reasonable time, to repair or replace any product to condition as warranted, the
Customer shall be entitled to a refund of the purchase price upon return of the product to Jackson
Labs.
1.2.2 Limitation of Warranty
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance
by the Customer, Customer-supplied software or interfacing, unauthorized modification or misuse,
opening of the instruments enclosure or removal of the instruments panels, operation outside of the
environmental or electrical specifications for the product, or improper site preparation and
maintenance. JACKSON LABS SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. No license, express or implied, by estoppel or otherwise, to any intellectual
property rights is granted by this document. Jackson Labs products are not intended for use in
medical, life saving, or life sustaining applications.
1.2.3 Exclusive Remedies
THE REMEDIES PROVIDED HEREIN ARE THE CUSTOMER'S SOLE AND EXCLUSIVE
REMEDIES. JACKSON LABS SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT,
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON
CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
1.2.4 Safety Summary
The following general safety precautions must be observed during all phases of operation of this
instrument. Failure to comply with these precautions or with specific warnings elsewhere in this
manual violates safety standards of design manufacture, and intended use of the instrument. Jackson
Labs assumes no liability for the customer’s failure to comply with these requirements.

© 2006 Jackson-Labs 3
FireFox Synthesizer User Manual
1.3 General
1.3.1 Environmental Conditions
This instrument is intended for indoor use. It is designed to operate at a maximum relative
non-condensing humidity of 95% and at altitudes of up to 4000 meters. Refer to the specifications
tables for the ac mains voltage requirements and ambient operating temperature range.
1.3.2 Line Power and Grounding
The FireFox Desktop unit operates on a 100V to 220V, 43Hz to 65Hz AC power input with typically
less than 20W power consumption. The FireFox OEM unit operates on a 12.0V regulated DC input
with typically less than 1A input current. Both units are designed to be continuously powered to keep
the GPS receiver and OCXO warmed-up and locked.
The FireFox desktop unit requires a three-pronged AC power plug with proper grounding to prevent
electrocution hazards. All BNC and SMA connector shields are grounded, and should not be
connected to any voltage sources. To minimize shock hazard, the instrument chassis and cabinet must
be connected to an electrical ground. The instrument must be connected to the ac power supply mains
through a three-conductor power cable, with the third wire firmly connected to an electrical ground
(safety ground) at the power outlet. Any interruption of the protective (grounding) conductor or
disconnection of the protective earth terminal will cause a potential shock hazard that could result in
personal injury. If the instrument is to be energized via an external autotransformer for voltage
reduction, be certain that the autotransformer common terminal is connected to the neutral (earthed
pole) of the ac power lines (supply mains).
1.3.3 Line Fuse
Fuses are internal to the instrument and are not user-serviceable. All repairs should be referred to a
qualified service technician. The FireFox OEM module uses a self-resettable Polyfuse that will
correct itself once the fault or overload condition is removed.
1.3.4 Do not operate the Instrument in an Explosive
Atmosphere
Do not operate the instrument in the presence of flammable gases or fumes. The instrument contains
mechanical switches and relays that could cause sparks and thus ignition of flammable gases or
fumes.
1.3.5 Keep away from Live Circuits
Operating personnel must not remove instrument covers. Component replacement and internal
adjustments must be made by qualified service personnel. Do not replace components with power
cable connected. Under certain conditions, dangerous voltages may exist even with the power cable

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removed. To avoid injuries, always disconnect power, discharge circuits and remove external voltage
sources before touching components.
1.3.6 Do not Service or Adjust alone
Do not attempt internal service or adjustment unless another person, capable of rendering first aid
and resuscitation, is present.
1.3.7 Do not exceed Ratings
This instrument is equipped with a line filter to reduce electromagnetic interference and must be
connected to a properly grounded receptacle to minimize electric shock hazard. Operation at line
voltages or frequencies in excess of those stated on the data plate may cause unsafe leakage currents.
1.3.8 Do not substitute parts or modify the Instrument
Do not install substitute parts or perform any unauthorized modifications to the instrument. Return
the instrument to Jackson Labs for service and repair to ensure that safety features are maintained.
Instruments that appear damaged or defective should be made inoperative and secured against
unintended operation until they can be repaired by qualified service personnel.
1.3.9 Operational Warning
Do not operate the FireFox desktop unit without its covers in place. Life line voltages are present
inside the case, and could cause bodily harm or death when the unit is operated without its covers in
place.

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FireFox Synthesizer User Manual
1.4 Quick Start Instructions
The following paragraphs describe the basic operational procedures to use the FireFox unit. The user
interface for the FireFox OEM board and the FireFox Desktop unit are essentially identical.
1.4.1 Connecting the instrument
Connect the AC power cord to the rear panel power connector. The unit will operate from 100V to
240V AC. See Figure 1.6 for the FireFox rear-panel connectors. Connect the factory-supplied GPS
antenna to the GPS BNC connector on the rear panel. By default, the unit is configured to supply 5V
to the GPS antenna. Jumper JP4 inside the unit can be used to select 3.3V antenna interfaces. Please
note that opening the unit will void the factory warranty.
1.4.2 Initializing the GPS
Every time the FireFox unit is moved, it is recommended to enable the GPS Automatic Site Survey
mode (or AutoSurvey) in order to reacquire its exact new position. The autosurvey algorithm
averages a total of 10000 valid position fixes and typically takes about 2-3 hours to finish. Once the
position is surveyed, the GPS will automatically enter the Position-Hold mode. In Position-Hold
mode, the GPS receiver no longer solves for position and only one satellite is required to accurately
determine time.
The Autosurvey activation is located in the SETUP->GPS menu section.
For a better position accuracy, it is also recommended to setup the Antenna Cable Delay in the GPS
Config menu.
Caveat: the unit contains an internal maintenance-free rechargable battery that will keep the time,
date, position, and GPS almanac alive inside the GPS receiver for ca. 3 hour long power failures.
Figure 1.1 FireFox Desktop Unit Front Panel

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After a certain time, the voltage on the battery will drop to a level at which the GPS real time clock
ceases to run. The GPS unit will continue to hold the data in its memory for several days after this
happens, but the time and date will not be updated anymore. This may cause the unit to turn on with
an internal time/date that is stale (old by several days), causing the GPS receiver to search for a
satellite constellation that presently does not exist. This may cause the GPS receiver to require a
significantly longer time to first fix (TTFF) than if the battery was completely discharged. It may take
up to 12 hours for the GPS receiver to start the Auto-Survey process under this fault condition.
To speed up the TTFF in this condition, the user may configure the unit to be remotely controlled
(Communication->GPS->Remote). To do this, connect a PC to the GPS-Serial connector on the back
of the unit, and use WinOncore12 to set the time and date of the GPS receiver. WinOncore12 has a
configuration wizard for this purpose (see the FAQ/GPS section on www.jackson-labs.com for
information on where to download WinOncore12).
1.4.3 Setting up the GPS
1.4.3.1 GPS Time Offset
The FireFox Signal Generator requires the user to set the political time offset to GMT time. Enter the
SETUP->GPS->GPS TIME OFFSET menu and select between -12 to +12 hours of time offset to
Greenwich Mean Time (GMT)
1.4.3.2 Selecting Metric/US Mode
The unit may display GPS height, time, and date in either Metric or US mode. Select the
SETUP->TIME->US/METRIC menu to change the setting of the relevant GPS data in the LCD
Display.
1.4.3.3 GPS Auto Survey
Enter the SETUP->GPS->AUTO SURVEY menu to start the GPS Auto Survey mode. This will
initiate the GPS receiver to build an average position using 10,000 position readings, and to store this
average position in its’ memory to improve the timing accuracy. Operating with the averaged
position is called Position Hold mode. Pressing the enter key in this menu will re-initiate the Auto
Survey mode. The FireFox will indicate the Auto Survey mode by displaying “AS” in the main
frequency setting window above the “STAT” indicator. Operating in Position Hold mode is indicated
by an “OK” display above the “STAT” indicator.
1.4.4 Setting the Frequency
Figure 1.1 shows the front panel LCD and keys used to change the output frequency of the FireFox
Signal Generator. The LCD shows either the frequency setting mode, or the menu mode. The
frequency setting mode is the default mode after power up. Press the menu key until the unit shows
the frequency setting mode if the unit is in any of the sub-menus. The left and right keys now control
the cursor which can be moved onto any of the frequency triplets, or onto the RF output power
setting. The cursor will wrap-around the display automatically.

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Use the up and down keys to change the frequency triplet. You may also press and hold the up or
down keys to automatically scan through the frequency range. The speed of the scan will increase
after a short time intervall.
When scanning the frequency using the down key, the display will show 0Hz after some time if the
selected frequency triplet has been reduced to 0Hz. Release the down key, then press and hold the
down key again to start scanning the frequency triplet below the one originally selected. The
frequency scanning in this mode will then start at 999....Hz.
As an example, set the frequency to 10.0MHz. Now place the cursor onto the 0 digit of the 10MHz
triplet (the single-MHz digit). Press and hold the down key, and the frequency will scan through 9, 8,
7.... 0 MHz. The display will now show “Uncal! 0MHz”. Release the down key, and press and hold it
again. The cursor will now be automatically placed onto the 1KHz digit, and down-scanning of the
frequency will commence at 999KHz.
A menu item for the upper frequency limit can be set to limit the highest frequency the unit can
generate. This item is accessible in the SETUP->OUTPUTS->FREQ-LIMIT menu. You may select
any frequency as the upper limit in this menu, and the unit will then not allow higher frequencies to
be selected from the front panel. Check the frequency limit setting if you are not able to configure the
unit to generate signals up to the 1.64GHz maximum frequency.
1.4.5 Setting the RF Amplitude
The unit has an analog RF output connector that will provide a sine wave for 50 Ohm terminated
loads. The RF output is enabled for frequencies from 2MHz to 1640MHz. The VALID LED next to
the RF-OUT BNC connector indicates if the selected frequency is within the range of the RF-OUT
connector. The power level of the output sine wave may be controlled via the front panel keypad. The
unit has two output level selecting modes:
•Relative output level ranging from 0% to 100%
•Calibrated absolute output level from -40dBm to +10dBm.
Select the mode in SETUP->OUTPUT->POWER UNIT
The relative output mode allows the unit to produce its maximum output power which may range
from +7dBm to over +18dBm depending on the frequency. The absolute output power mode will
generate a calibrated output power into a resistive 50 Ohm load connected directly at the RF output
connector on the front of the unit with typically better than +-0.2dBm accuracy and 0.02dBm
resolution.
Move the cursor onto the RF amplitude digits in the frequency setting mode. Press the up or down
keys to change the output power.
The unit also has a power limit menu similar to the frequency limit menu explained in paragraph
1.4.4 . Please check the power limit in the SETUP->OUTPUT->POWER LIMIT menu if you are
unable to select a desired power level up to 100% or +10dBm.

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1.4.6 Using the CMOS and LVDS outputs
The FireFox unit is unique in that it can produce both analog (sine wave) outputs, and digital outputs
simultaneously. Four front panel digital outputs are available. All four outputs on the front panel are
driven in parallel, within their respective output frequency ranges as indicated by the VALID LED’s.
Please note that the LVDS outputs have an under-range from 2-10MHz. The outputs are driven in this
under-range, but are not guaranteed to be jitter-free. The CMOS output is usable from 0Hz to
350MHz, with an over-range up to 390MHz in which the output is driven and usable but not
guaranteed to be jitter-free.
1.4.6.1 Connecting a cable to the LVDS Outputs
Two differential, complementary LVDS signals are available on SMA connectors on the front panel
of the FireFox unit. Typically LVDS signals are connected to 50 Ohm transmission lines (cables) and
differentially end-terminated with a 100 Ohm termination resistor between the Positive and Negative
LVDS signals. The user may also end-terminate the signals individually to Ground using 50 Ohm
end-terminators. The output voltage levels will change slightly when terminating to Ground.
By using 50 Ohm ground terminated cables it may be possible to drive PECL inputs. A series
capacitor may also be used to remove the LVDS DC-Offset present on the LVDS SMA connectors.
The signal swing on the two LVDS connectors is approximately 300mV peak on each output, and
this may be used to drive two independent analog inputs with ca. -7dBm level when connected via
AC-coupling.
1.4.6.2 Connecting a cable to the CMOS Output
The FireFox CMOS output is designed to drive a 50 Ohm transmission line or cable without any
end-termination (open-ended cable). Voltage levels are up to 5Vpp when using open-ended cables.
The FireFox CMOS output may also drive 50 Ohm end-terminated cables without damage and with
a slightly more than 50% reduction on the high-level output voltage. The rise and fall times of the
FireFox CMOS output are on the order of 1V/ns or faster.
Please note that the CMOS output is low-pass filtered for output frequencies below 30MHz to reduce
DDS-generated spurs above 30MHz, and thus to reduce the output jitter. The CMOS output provides
the output signal with the least spurs present for output frequencies below 30MHz of all of the
FireFox front-panel outputs.
1.4.6.3 Selecting the Front Panel CMOS Output Voltage
The Front Panel CMOS peak-to-peak output voltage is selectable via a switch on the back panel of
the FireFox Desktop unit, and via a Jumper on the FireFox OEM PCB. The switch is visible in the
upper left hand corner of Figure 1.6. Use JP12 located close to the CMOS output BNC connector to
select the CMOS output voltage when using the FireFox OEM PCB.
The CMOS output voltage can be selected to be either 0V to 3.3V, or 0V to 5.0V when driving
un-terminated transmission lines. This voltage level will be reduced by slightly more than 50% when
driving an end-terminated 50 Ohm transmission line.

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1.4.7 Setting up the DDS
Enter the menu SETUP->DDS to control the internal settings of the FireFox Signal Generator RF
DDS (Digital Direct Signal Generator).
1.4.7.1 Setting the Phase Offset
Enter the SETUP->DDS->PHASE OFFSET menu item to control the output Frequencies’ phase in
relation to the rear panel 10MHz time base output. The user can select the phase in small increments
from -180 Degrees to +180 Degrees.
1.4.7.2 Mixer ON/OFF
The FireFox Signal Generator has a general-purpose, non-dedicated 2GHz Bandwidth mixer built-in,
accessible through the front panel BNC connectors.
This mixer can be turned ON or OFF via the SETUP->DDS->MIXER menu.
Turning off the mixer may help prevent some spurs, and may be usefull when debugging IF and AGC
circuitry etc.
1.4.7.3 FRACT ON/OFF
The menu item SETUP->DDS->FRACT ON/OFF determines the mode of the FireFox Signal
Generator Fractional-N DDS to be used or to be disabled. This setting determines the FireFox Signal
Generator resolution, and also affects the output phase noise and frequency drift. Select FRACT ON
to set the DDS to 48-bit Frequency mode, or FRACT OFF to turn off the Fractional-N mode, and set
the unit to 32-bit Frequency mode.
See Section 3.6.6 for an in-depth discussion of the Fractional-N operating mode.
1.4.7.4 Noise/Spur Optimization
The menu item SETUP->DDS->NOISE/SPUR OPT allows the internal FireFox PLLs’ to be setup
for either best-noise performance (Spur optimization turned to OFF) or best-spur performance (Spur
optimization turned to ON). This setting will affect the PLL charge currents of the internal PLLs’ and
place these either in the best operating mode for Phase Noise performance, or for least-Spur
performance.
Set this item to OFF for typical operations that require low phase-noise signals.
1.4.8 Setting up the Output
The following settings affect the FireFox maximum frequency that can be generated, as well as the
analog front panel RF Output power.
1.4.8.1 Frequency Limit
In the SETUP->OUTPUT->FREQ LIMIT menu the user may limit the maximum possible frequency
that can be set via the front panel keys in the frequency setting menu. This setting will also affect
sweep modes, and memory recall modes.

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The unit will not generate Frequencies above the limit Frequency selected in this menu item.
The limit Frequency will be stored in non-volatile memory until changed in this menu item.
1.4.8.2 Power Unit
In the SETUP->OUTPUT->POWER UNIT menu the user may select either a relative power output
ranging from 0% to 100% of the units’ power output capability, or an absolute output power selected
in dBm (between -40dBm to +10dBm).
Setting relative mode is useful if the maximum power output at any given frequency is desired from
the analog RF Output BNC connector on the front panel. The maximum output power in relative
mode can range from +5dBm to over +18dBm depending on the output frequency.
Setting absolute mode will allow the unit to generate RF signals with high level-accuracy (typically
within +-0.2dBm at an output power of 0dBm). The range of the output power is limited to -40dBm
to +10dBm in absolute mode.
This setting only affects the analog RF Output BNC connector on the front panel. All other signal
outputs remain unaffected by this setting.
1.4.8.3 Power Limit
In the SETUP->OUTPUT->POWER LIMIT menu the user may limit the maximum possible analog
RF Output Power that can be set via the front panel keys in the frequency setting menu. This setting
will also affect sweep modes, and memory recall modes.
The unit will not generate Power levels above the limit Frequency selected in this menu item on the
analog RF Output BNC front panel connector.
The limit Power will be stored in non-volatile memory until changed in this menu item.
This setting only affects the analog RF Output BNC connector on the front panel. All other signal
outputs remain unaffected by this setting.
1.4.9 Setting up Frequency Sweeps
The unit can be used as a sweeping signal generator. The following parameters are selectable through
the keypad menu:
•frequency start (F1, from 0 to 1.64 Ghz)
•frequency stop (F2, from 0 to 1.64 Ghz). The stop frequency has to be different to the start
frequency and may be selected to be lower than the start frequency.
•duration (D) of the sweep from 0.1s to 1000s with a resolution of 0.1s.
•sweep spacing (pace): linear or logarithmic
•sweep mode:
– from F1 to F2, single sweep only
– from F1 to F2 and back from F2 to F1, single sweep only. In this case the total duration of the
sweep time is doubled.
– from F1 to F2 continuously sweeping until the Right key is pressed. Every sweep from F1 to
F2 will have a duration D, and the unit will restart at F1 once F2 has been reached.

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– from F1 to F2 back and forth from F2 to F1 continuously sweeping until the Right key is
pressed. Every sweep from F1 to F2 or F2 to F1 will have a duration D.
The sweep settings are accessible directly from the main menu SWEEP.
1.4.10 Monitoring the Instrument Status
1.4.10.1 OCXO Status
The FireFox Signal Generator allows its internal status to be monitored via the STATUS/OCXO menu
item. The OCXO temperature, the OCXO EFC DAC value, the estimated 30 minute Allan Deviation,
and the GPS pulse number can be monitored when accessing this menu item.
The EFC status shows the value of the present DAC setting from 0% to 100%. This value is typically
between 50% and 60%, and should only change slowly over time.
The Freq Est number displayed shows the estimated Allan Deviation for a measurement interval of
30 minutes (1800s). This number is calculated by taking the phase offset measurement between the
GPS 1PPS output, and the internal OCXO 1PPS signal, waiting 30 minutes, then comparing this
value to the present phase offset and calculating the error in one minute updates.
The OCXO temperature shown is measured at the outside of the metal cage of the OCXO, and should
typically be between 45 and 65 Degrees Celsius.
The 1PPS pulse count shows how many 1PPS pulses have been received from the GPS timing
receiver. At least 3600 pulses need to be received for the Freq Est to be calculated correctly.
1.4.10.2 GPS Status
The GPS status menu item will display the stored GPS hold-mode position and altitude. The GPS
receiver firmware version can also be checked in this menu item.
The GPS status is also displayed in the LCD main frequency setting menu, on the right hand side
above the “SAT” and “STAT” indicator. The meaning of these indicators is as follows:
LCD STAT indicator Meaning
OK The unit is receiving at least one Satellite, and is locked to
better than 15E-011 to UTC
AQ The unit is searching for Satellites (Acquiring)
AS The unit is receiving at least 4 Satellites, and is in Auto
Survey mode
2D, 3D The unit is receiving at least 3 to 4 Satellites, and Position
Hold Mode has been de-selected, or the unit is entering
Auto Survey mode
Table 1-1: GPS Status Indicator Abbreviations

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1.4.10.3 Sys Config
This menu item will show various FireFox system parameters.
The first item in the LCD is the FireFox Signal Generator Firmware version. SCPI commands are
available with Firmware Version 3.0 or later.
The GPS type is displayed. The M12+ or M12M receivers are used in the FireFox Signal Generator.
The MTI OCXO version is displayed in this menu item. The single oven default OCXO is
MTI230-0827. The double oven OCXO option is MTI270-0269
The last display item is DDS Resolution. The DDS resolution is the internal resolution limit due to
the 48 bit DDS setup. The smallest DDS step size is 1.7764microhertz, and the highest step size is
14.2109microhertz, depending on the output frequency. The system will generate an output
frequency closest to the desired frequency, with a step size displayed in the LCD.
1.4.11 Using the External Mixer
The FireFox Signal Generator includes a general purpose mixer accessible from the front panel. A
mixer is used to generate a signal consisting of the difference of two input signals. Mixers can be
used to shift high-frequency signals into lower frequency bands, or vice versa.
As an example, the FireFox Signal Generator can be used to modulate baseband video signals to RF
channel frequencies. Analog or Digital signals such as DVB-T baseband signals can be upconverted
to RF frequencies up to about 400MHz. To RF modulate an I/Q baseband DVB-T video signal to an
RF carrier of 61.25MHz, simply set the RF output of the FireFox Signal Generator to 61.25MHz,
feed the RF output into the LO Mixer input (set the RF output amplitude to 0dBm, making sure not
to exceed the Mixer input damage level of +10dBm), and feed the DVB-T baseband signal into the
mixers RF input. The Mixer output will now contain a DVB-T modulated signal with a 61.25MHz
carrier. A VSB filter may have to be used to properly format the signal.
The mixer is also useful when trying to receive high frequency signals; see the following example:
An FM modulated signal at 1.40GHz is to be received using the FireFox and a standard FM radio.
The input signal has to be transformed from 1.40GHz to 100MHz to be receivable by the FM Radio.
For this example, we will select a Local Oscillator (LO) Frequency of 1.50GHz. The LO input is
simply driven by the FireFox RF output signal via a BNC jumper cable, so the FireFox is set to
generate the 1.5GHz. The received RF input signal is then connected to the RF input. Mixing the
1.5GHz LO frequency with the 1.4GHz RF signal will generate a 100MHz mixing product (the
Intermediate Frequency, or IF signal), which is basically the RF signal shifted to 100MHz. The IF
output can now be connected to the FM radio tuned to 100MHz. The received signal will now be
audible by the radio.
UL The OCXO is not locked to UTC (Unlocked)
BG The unit is receiving sufficient Satellites for Auto Survey
mode, but the Satellite Geometry is bad and the present
Satellites cannot be used (Bad Geometry)
LCD STAT indicator Meaning
Table 1-1: GPS Status Indicator Abbreviations

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Typical signal levels at the mixer inputs are -20dBm to 5 dBm for the RF input, and 0dbm for the LO
input. Care must be exercised to avoid driving the Mixer RF and LO inputs above 10dbm. Driving
the inputs above this level could damage the mixer.
The mixer can be disabled in the menu settings to reduce potential interference.
1.4.12 Storing and Recalling Setups
The FireFox unit can store up to 10 independent setups in its internal Non Volatile memory. To store,
recall, and erase setups, enter the Memory menu by pressing MEMORY->RECALL/SAVE/ERASE.
Once inside the SAVE or RECALL menu items, press the UP or DOWN key to select a memory
position to save to, or recall from. Positions 0 to 9 are selectable.
An empty memory position is indicated by a “-” sign, an occupied position is indicated by a “*” sign.
Save a memory setup by pressing the ENTER key in the SAVE menu. You may exit the save menu
by pressing the EXIT/MENU key.
Recall a memory location by pressing the ENTER key in the RECALL menu. You can exit without
recalling by pressing the EXIT/MENU key.
The user may erase only the entire memory. This is useful if all memory locations have been
filled-up, and the older data is no longer useful.
Erase all memory positions by pressing ENTER in the ERASE menu. Exit the erase menu without
erasing any data by pressing the EXIT/MENU button.
All FireFox settings such as Maximum Frequency, Power settings, the Frequency, Power Unit, output
power and other settings are saved in these memory locations.
Please note that GPS relevant data such as the GPS position in Position Hold mode, the GPS GMT
time offset, etc. are not maintained in these memory locations, but rather inside the GPS itself.
1.4.13 Using the GPS and OCXO Reference Outputs
1.4.13.1 GPS Receiver 1PPS Output
The FireFox Signal Generator provides a highly stable 1PPS CMOS 3.3V compatible output pulse on
its’ rear panel 1PPS BNC connector. This pulse is derived from the Motorola M12+ GPS Timing
receiver. It does exhibit the typical M12+ sawtooth waveform, which may be compensated by using
the Motorola Clock Granularity Message available on the rear panel GPS RS-232 port. See the
Motorola M12+ documentation about details of how to use these two outputs.
The rear panel 1PPS output is buffered by a high-speed, 3.3Vpp CMOS output, and this output
should typically drive an open-ended 50 Ohm transmission line/cable. Terminating the output with a
50 Ohm resistor will not damage the output, but will significantly reduce its output voltage swing.
The CMOS buffer adds ca. 6ns of Tpd propagation delay to the GPS receivers’ 1PPS output signal;
this delay may be compensated in the receiver by using the Antenna Cable Delay setting available
when connecting the WinOncore12 software to the GPS receiver. See section 1.4.14.3 and section
3.5.3 for details about the WinOncore12 software.

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1.4.13.2 OCXO Timing Reference Output
The rear panel 10MHz time-base reference output is highly accurate, and disciplined by the GPS
receiver. This output is driven by a high-speed CMOS driver with 3.3Vpp output drive voltage. This
output may either drive a non-terminated 50 Ohm transmission line/cable, or it may drive an
end-terminated cable. The output voltage will be reduced by 50% if the BNC cable is end terminated
with a 50 Ohm resistor. See Figure 1.2 for typical stability data for this 10MHz output signal.
The unit will require between 3 to 10 hours to stabilize fully when turned on from a cold-start. The
OCXO crystal may take up to one week to fully stabilize and to have periodic frequency shifts seize
to appear, especially if the unit has recently been moved, shipped, or has experienced significant
thermal changes.
The 30 minute Allan Deviation Estimate of this output is available in the FREQ EST display item
when entering the STATUS->OCXO menu item. This estimation is calculated by measuring the
internal OCXO generated 1PPS signal phase shift to the GPS generated 1PPS signal, and comparing
the momentary value to the value calculated 30 minutes previously. The deviation is then calculated,
and displayed in the LCD. Typical deviation numbers when the unit has been locked and operating
for several weeks are <+-5E-010 for the default OCXO option, and <+-5E-011 for the Double Oven
Ultra High Stability OCXO option.
1.4.14 Advanced GPS Setup
1.4.14.1 Factory Reset
Pressing the enter button in the SETUP->GPS->FACTORY RESET menu will initiate a GPS receiver
Factory Reset, and reset all of the stored settings of the FireFox Signal Generator. Please power cycle
the unit after initiating this command.
This command requires the user to re-initiate all of the settings such as Power Unit, GPS Time Offset,
Maximum Frequency and Maximum Power etc.
It is recommended that a Factory Reset is only initiated if the unit stops responding correctly to user
commands.
1.4.14.2 GPS TRAIM Filter
The GPS receiver can operate with an internal TRAIM (Time Receiver Autonomous Integrity
Monitoring) algorithm to ensure that data from bad Satellites will not corrupt the FireFox Signal
Generator Time Base accuracy. The receiver requires at least 4 Satellites to be received and to be in
good status when entering the SETUP->GPS->GPS TRAIM FILTER menu and selecting GPS 1PPS
FILTER ON. Any Satellite solutions with less than 4 Sats being received, or with any one Sat
exceeding 300ns deviation from the others will be considered stale by the GPS firmware when this
option is set to ON.
Jackson Labs recommends maintaining this setting in the OFF position when using the default
FireFox Signal Generator OCXO, and only setting this option to ON when using the
ultra-high-stability double-oven OCXO option with a GPS Antenna that has a clear view of the sky.