5401 Airborne Disciplined Rubidium Oscillator 5402 Disciplined Rubidium Oscillator Operating Manual Preliminary Rev.
Symmetricom, Inc. 2300 Orchard Parkway San Jose, CA 95131-1017 U.S.A. http://www.symmetricom.com Copyright © 1999–2005 Symmetricom, Inc. All rights reserved. Printed in U.S.A. This manual is provided to assist the user in the operation and maintenance of the supplied equipment or software.
Operating Manual Preface Preface Limited Warranty Each new product manufactured by Symmetricom is warranted for defects in material or workmanship for a period of one year from date of shipment (“Limited Warranty”). Defects in material or workmanship found within that period will be replaced or repaired, at Symmetricom’s option, without charge for material or labor, provided the customer returns the equipment, freight prepaid, to the Symmetricom factory under this limited warranty.
Operating Manual Preface Limitation of Liability By purchasing any product from Symmetricom, the Buyer consents to and agrees that the Buyer’s sole and exclusive remedy for any damages or losses incurred by the Buyer as a result of Symmetricom’s breach of its one-year Limited Warranty for defects in materials and workmanship or otherwise in connection with any claim respecting the product shall be limited to the repair or replacement of the product or a refund of the sales price of the product.
Operating Manual Preface ESD Caution: To avoid personal injury and electrostatic discharge (ESD) damage to equipment, do not disregard ESD cautions. All ESD cautions use this symbol. ESD cautions are installation, operation, or maintenance procedures, practices, conditions, or statements that if not strictly observed, may result in possible personal injury, electrostatic discharge damage to, or destruction of, static-sensitive components of the equipment.
Operating Manual Preface Table 2 Typographical Conventions When text appears this way... ... it means: SSU-2000 User’s Guide The title of a document. SSU CRITICAL IOC1 An operating mode, alarm state, status, or chassis label. Select File, Open... Click the Open option on the File menu. Press Enter Press ; A named keyboard key. The key name is shown as it appears on the keyboard. An explanation of the key’s acronym or function immediately follows the first reference to the key, if required.
Operating Manual Contents Preface Limited Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Limitation of Liability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Proprietary Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Where to Find Answers to Product and Document Questions . . . . . . . . . . . . .
Operating Manual Burst Status On. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Burst Status Off. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Request TI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Enter DAC Value. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Request Firmware Version . . . . . . . . . . . . . . . . . . . .
Operating Manual Introduction 1 — Introduction Product Overview The purpose of the Symmetricom 5401 Airborne Disciplined Rubidium and 5402 Disciplined Rubidium Oscillator (DRO) is to provide a precise time and frequency reference for other equipment. The DRO will base this reference on a precise 1 PPS input, typically from a GPS Receiver. At the 1 PPS time signal input rollover, the DRO will measure the time difference between it and the internal Rubidium oscillator.
Operating Manual Introduction Symmetricom 5401 Airborne Disciplined Rubidium Oscillator The Symmetricom 5401 is built in an airborne package that is powered by standard aircraft power (+28 VDC) and is installed by mounting the chassis on a flat base plate. Refer to Chapter 4 for complete specifications.
Operating Manual Installation 2 — Installation Installation This section describes the unpacking, inspection, installation, and operation of the Symmetricom 5401 and 5402 Disciplined Rubidium Oscillators. Unpacking and Inspection The DRO is packaged in one shipping container. Inspect the unit for visible damage (scratches, dents, etc.). If the instrument is damaged, immediately notify both Symmetricom and the responsible carrier.
Operating Manual Installation The 5401 is now operational and will begin to discipline the Rubidium using the control parameters that were previously stored in battery-backed RAM when the unit was last powered-down. Symmetricom 5401 Adjustments The amplitude of each of the 10 MHz outputs can be individually adjusted with potentiometers located on the 3-Channel Distribution Amplifier (Assembly 35039). In order to gain access to these adjustments, do the following: (The 5401 is viewed from the rear.) 1.
Operating Manual Installation Symmetricom 5402 Rack Mounting Procedure The 5402 is designed for standard nineteen-inch rack mounting. Optional chassis slides are recommended if the unit is to be installed in an equipment rack. If slides are not used, a supporting bar or tray should be provided for the rear of the instrument. The chassis slides attach to the sides of the 5402. To mount the slides, use six # 8/32 screws, 1/2 inch long (three on each side).
Operating Manual Installation Symmetricom 5402 Installation Procedure 1. Install the unit in the desired location and connect the unit to an AC power source. Refer to Chapter 4 for specifications and connector designations and locations. 2. Connect the 1 PPS input to its 1 PPS source and connect the 1 PPS and 10 MHz outputs to their desired destinations. Connection to the RS232 I/O is not necessary for operation, but it is desirable in order to monitor status or enter new control parameters.
Operating Manual Operation 3 — Operation Neither the 5401 nor the 5402 have any external manual controls. Signal output amplitude is controlled by internal potentiometers, which are located as described in Chapter 2. All operational control of the DRO is accomplished by means of an RS-232 input/output port. RS-232 Input/Output The DRO has been equipped with an RS-232 interface using a 13-pin MS type connector designated as J14 RS232 on the 5401, and using a DB15 connector designated as J3 on the 5402.
Operating Manual Operation Table 1 DRO Commands Via RS-232 Status Request Command Format: PN 8500-0150, Rev.
Operating Manual Operation Description: Rx - Rubidium lock; x=0 not Locked, x=1 Locked Dx - Discipline On/Off; x=0 discipline off, x=1 discipline on Px - 1 PPS input present; x=0 not present, x=1 present Vx - Valid 1 PPs; x=0 unstable, x=1 stable. Time change in the 1 PPS is less than the rate threshold. Ttttttt.ttt - Time Interval; tttttt.ttt is the time interval (0 to 999999.999 microseconds) of the last 1 PPS event. Sssssss.s - Seconds Counter; ssssss.s is the second count (0 to 999999.
Operating Manual Operation Response Format: Discipline On Command Format: Description: The oscillator discipline is turned on. When the conditions are favorable, the discipline algorithm will control the oscillator. Response Format: Dynamic Gain Control Command Format: Description: The dynamic gain value determines the response time of the control loop. This command sets the upper and lower limit. Fgg.g - Dynamic Gain Floor; the lowest value allowed for dynamic gain. Cgg.
Operating Manual Operation Dynamic Gain Time Constant 4 90 minutes 5 70 minutes 8 45 minutes 10 35 minutes 20 17 minutes 30 11 minutes Response Format: Enter KM Command Format: Description: kkkkkk - Base number for Km; kkkkkk (000000 to 999999) represents a number from 0 to 0.999999. Km controls the mix ratio of offset error and frequency error compensation in the discipline algorithm. Response Format: Enter KO1, KO2 Command Format: PN 8500-0150, Rev.
Operating Manual Operation Description: nnnnnn - Base number for Ko1; nnnnnn (000000 to 999999) represents a number from 0 to 0.999999. Ko1 controls the cut off frequency of the offset error noise filter. oooooo - Base number for Ko2; oooooo (000000 to 999999) represents a number from 0 to 0.999999. Ko2 controls the cut off frequency of the frequency error noise filter.
Operating Manual Operation Enter Resync Delay When the 1 PPS In is lost or becomes invalid (rate threshold is exceeded), the unit is placed into a holdover mode. It remains in this mode until the 1 PPS In is valid for a time period (in seconds) determined by "Resync Delay". At five seconds before discipline restarts, a determination is made as to whether the 1 PPS Out will be resynchronized (jammed). This is based on the "Resync Delay". Refer to the Discipline Sequence flowchart in Figure 5.
Operating Manual Operation Burst Status On Command Format: Description: Status will be output every second. Response Format: Burst Status Off Command Format: Description: Turns burst status off. Response Format: No Response. When burst is on. When burst is off: PN 8500-0150, Rev.
Operating Manual Operation Figure 5 DRO Discipline Sequence Flowchart Request TI Command Format: PN 8500-0150, Rev.
Operating Manual Operation Description: Ttttttt.ttt - Time Interval; tttttt.ttt is the time interval (0 to 999999.999 microseconds) of the last 1 PPS event. Sssssss.s - Seconds Counter; ssssss.s is the second count (0 to 999999.9 seconds) since the unit has been turned on. The count will roll over to zero when maximum is reached. Response Format: Enter DAC Value Command Format: Description: ddddd - DAC Value; ddddd (0 to 65535 counts) controls the frequency of the oscillator.
Operating Manual Operation r - Revision Letter of Firmware. Response Format: Enter Start-up Parameters Command Format: Description: n - Start-up Index; n (1 to 6) selects which one of 6 elements in the start-up table that will be modified. gg.g - Dynamic Gain Value; gg.g (0 to 99.9) represents the dynamic gain value that will be used during start-up for element "n". tttttt - End Time; tttttt is the end time of element "n" (based on Rubidium lock).
Operating Manual Operation Response Format: Description: Nn - Start-up Index; n (1 to 6) identifies which one of 6 elements in the start-up table was reported. Ggg.g - Dynamic Gain Value; gg.g (0 to 99.9) represents the dynamic gain value that will be used during start-up for element "n". Ttttttt - End Time; tttttt is the end time of element "n". The next element in the start-up table will be used after this time. The time is the number of times the discipline loop has been run.
Operating Manual Operation Set Defaults Command Format: Description: Returns the unit to a default state. Table 2 Default Values Parameter Default Value Discipline On Dynamic Gain Floor 4 Dynamic Gain Ceiling 30 Dynamic Gain Rate Factor 0.0005 ns Dynamic Gain Offset Factor 5.0 ns Km 0.99997 Ko1 0.99984 Ko2 0.99984 Disgain 1280 Resync Threshold 1 µs Resync Delay 60 seconds Rate Threshold 0.
Operating Manual Operation Note 1: Start-up Parameters N Dynamic Gain Time 1 .1 360 2 99 1140 3 60 1740 4 30 2760 5 20 0 6 11 0 Response Format: Enter 1 PPS Offset (not implemented) Command Format: Description: yyyyyy.yyy - 1 PPS Offset; yyyyyy.yyy (0 to 999999.999 microseconds) is amount of extra delay applied to the 1 PPS output. It is added to the unit zero point and the resync side load value.
Operating Manual Operation Description: In Table 3 is a list of the data found in the response. The data is in the same format as the associated "Enter" command. A space exists between each of the parameters, except where noted. The total count is 176 characters. Table 3 Response Format Variable Return String Count First Dynamic Gain Floor DFgg.g 6 1 Dynamic Gain Ceiling DCgg.g 6 8 Dynamic Gain Rate Factor DRrr.
Operating Manual Operation Description: The input 1 PPS can be sliced at two deferent levels. This command selects which slicing level is used. x=0 - High 5 volt input threshold, x=1 - Low 2.5 volt input threshold. Response Format: Enter Programmable Delay Value Command Format: Description: The yyy is a number from 000 to 255. The number is the delay value sent to a programmable delay. The programmable delay moves the 1 PPS outputs and allows them to be aligned to the 10 MHz.
Operating Manual Operation The srr.rrrr is a number from -99.9999 to +99.9999 microseconds per second. The number is frequency change from DAC = 00000 to 65535 of the unit. This number is used in the discipline algorithm to help compensate for oscillators with different frequency Note: It is assumed that the DAC output and oscillator control are linear. If not, then the oscillator control range should be extrapolated from a subset of the control curve that is near zero frequency error.
Operating Manual Operation Cal Status Command Format: Description: Cx - Calibration status: x=0 not doing a calibration. x=1 calibration in progress. x=? last calibration failed (no 1 PPS, cable missing, noisy 1 PPS, or wrong 1 PPS). Response Format: Enter Estimation Filter Time Constant Command Format: Description: nnnnnn - Base number for the filtered rate exponential integrator; nnnnnn (000000 to 999999) represents a number from 0 to 0.999999.
Operating Manual Operation Enter Dynamic Gain Factors Command Format: Description: Rrr.rrrr - Rate Factor; the normalizing value (in nanoseconds) for rate when calculating the next dynamic gain. Oooo - Offset Factor; the normalizing value (in nanoseconds) for offset (TI) when calculating the next dynamic gain. Response Format: PN 8500-0150, Rev.
Operating Manual Specifications 4 — Specifications This section contains the electrical, physical, and environmental specifications for the 5401 and 5402 Disciplined Rubidium Oscillator. Input Specifications and Characteristics Table 4 Input Specifications and Characteristics 5401 DC Power Input (J15) Type MS27499E10B5P Connector Pin Assignments: Pin Function A Rubidium Lock Status B Chassis Ground C Not Used D +28 VDC (+18 to +36 VDC) (Approximately 2.5 amps at initial turn-on and 1.
Operating Manual Specifications Table 4 Input Specifications and Characteristics (Continued) 5401 RS-232 Input/Output Type MS27499E10B35S 5401 Connector Pin Assignments: Pin Function 1 Chassis Ground 2 Transmitted Data 3 Received Data 4 Signal Ground 5-13 Not Used 5402 RS232 Input/Output Type DB9 5402 Connector Pin Assignments: Pin Function 2 Transmitted Data 3 Received Data 5 Signal Ground DRO RS-232 Parameters: Baud 9600 Parity None Word Length 8 Bits Stop Bits 1 Output Spe
Operating Manual Specifications Table 5 Output Specifications and Characteristics (Continued) Coherencea The 1 PPS OUT time delay is < 10 nanoseconds from the mean of the 1 PPS Input Port to Port Isolation 90 dB Isolation (with respect to 1 PPS input) 90 dB DRO 10 MHz Output Type 5401: Isolated SMA (J7-J12) 5402: Isolated SMA (J10-J15) The DRO outputs 10 MHz signals with the following characteristics (After a 30 minute warm-up at an ambient temperature of 25ºC): Level 1.6 to 3.
Operating Manual Specifications 5401 Indicators (Front Panel) Table 6 5401 Indicators (Front Panel) Power (LED) Indicates power applied to the unit (see Figure 6). Lock (LED) Indicates Rubidium Locked status (see Figure 6). 5402 Indicators (Front Panel) Table 7 5402 Indicators (Front Panel) Power (LED) Indicates power applied to the unit (see Figure 7). DRO Internal Time Bases Table 8 DRO Internal Time Bases LPRO (Low Profile Rubidium Oscillator) Output Waveform 10 MHz sine wave Output Level 0.
Operating Manual Specifications Table 8 DRO Internal Time Bases (Continued) Spurs: Harmonic 50 dBc Non-Harmonic 90 dBc Input Voltage Range +19 to +32 VDC Input Power (Quiescent) 13 watts @ 25ºC (+24 VDC) 10 MHz Oven Oscillator Table 9 10 MHz Oven Oscillator Output Waveform 10 MHz sine wave Output Level 0.5 VRMS into 50 Output Impedance 50 Temperature Stability ±3 x 10-8 over a temperature range of –20ºC to +70ºC Short Term Stability t=1 second Aging 5 x 10-11 5 x 10-10/day, 1.
Operating Manual Specifications 5401 Dimensions Figure 6 5401 Mounting Dimensions 5401 Weight Approximately 8 pounds. 5402 Weight Approximately 10 pounds. PN 8500-0150, Rev.
Operating Manual Specifications 5402 Dimensions Height 1.
