Quartzlock | A5-12 | Specifications | Quartzlock A5-12 Specifications

Model E8 Series Operation Manual
MODEL E8 SERIES
GPS Timing & Frequency Standard
USER’S HANDBOOK
Quartzlock UK Ltd
Gothic,
Plymouth Road,
Totnes,
Devon
TQ9 5LH,
England.
Tel:
Fax:
Web:
E-mail:
+44 (0) 1803 862062
+44 (0) 1803 867962
www.quartzlock.com
quartzlock@quartzlock.com
E8 Series A5 Manual 9 October 2008
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Model E8 Series Operation Manual
Contents
Safety Considerations.......................................................................................................... 3
Voltage, Frequency and Power Characteristics ................................................................... 4
Environmental Conditions .................................................................................................... 4
Replaceable Fusing Characteristics .................................................................................... 4
Cleaning Instructions ........................................................................................................... 4
E8 Series GPS Timing & Frequency Reference .................................................................. 5
Introduction ...................................................................................................................... 5
Installation ........................................................................................................................ 5
Operation ......................................................................................................................... 5
Interface and programming .............................................................................................. 6
GPS interface ............................................................................................................... 6
Specifications ................................................................................................................... 8
OUTPUTS: ................................................................................................................... 8
Appendix A ..................................................................................................................... 10
Board set up ............................................................................................................... 10
Appendix B ..................................................................................................................... 11
RS232 control codes .................................................................................................. 11
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Model E8 Series Operation Manual
Safety Considerations
General
This product and related documentation must be reviewed for familiarisation before operation. If the
equipment is used in a manner not specified by the manufacturer, the protection provided by the
instrument may be impaired.
Before Applying Power
Verify that the product is set to match the available line voltage and the correct fuse is installed.
Before Cleaning
Disconnect the product from operating power before cleaning.
WARNING
Bodily injury or death may result from failure to heed a warning. Do not proceed beyond a warning
until the indicated conditions are fully understood and met.
CAUTION
Damage to equipment, or incorrect measurement data, may result from failure to heed a caution. Do
not proceed beyond a caution until the indicated conditions are fully understood and met.
This equipment must be earthed
An uninterruptible safety earth ground must be maintained from the mains power source to the
product’s ground circuitry.
WARNING
When measuring power line signals, be extremely careful and use a step down isolation transformer
whose output is compatible with the input measurement capabilities of this product. The product’s
front and rear panels are typically at earth ground. Thus, never try to measure AC power line signals
without an isolation transformer.
WARNING
Instructions for adjustments when covers are removed and for servicing are for use by servicetrained personnel only. To avoid dangerous electrical shock, do not perform such adjustments or
servicing unless qualified to do so.
WARNING
Any interruption of the protective grounding conductor (inside or outside the instrument) or
disconnecting of the protective earth terminal will cause a potential shock hazard that could result in
personal injury. Grounding one conductor of a two conductor out-let is not sufficient protection.
Whenever it is likely that the protection has been impaired, the instrument must be made inoperative
and be secured against any unintended operation.
If the instrument is to be energised via an autotransformer (for voltage reduction) makes sure the
common terminal is connected to the earthed pole terminal (neutral) of the power source.
Instructions for adjustments while the covers are removed and for servicing are for use by servicetrained personnel only. To avoid dangerous electrical shock, do not perform such adjustments or
servicing unless qualified to do so.
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Model E8 Series Operation Manual
For continued protections against fire, replace the line fuse(s) with fuses of the same current rating
and type (for example, normal blow time delay). Do not use repaired fuses of short-circuited fuse
holders.
Voltage, Frequency and Power Characteristics
AC Power Adaptor
Voltage 100-240V AC
Frequency 40-50Hz
Power characteristics 500mA Max
Voltage 12V dc 300mA – 500mA
Environmental Conditions
Temperature
Operating (ambient)
-10°C to +55°C (-65 to +65 op)
Storage
-40°C to +85°C
Magnetic Field
Sensitivity
≤2x10-11/ Gauss
Atmospheric Pressure
-60m to 4000m
<1x10-13/ mbar
Replaceable Fusing Characteristics
N/A
Cleaning Instructions
To ensure long and trouble operation, keep the unit free from dust and use care with liquids around
the unit.
Be careful not to spill liquids onto the unit. If the unit does get wet, turn the power off immediately
and let the unit dry completely before turning it on again.
Clean with a damp (with water) cloth.
Never spray cleaner directly onto the unit or let liquid run into any part of it. Never use harsh or
caustic products to clean the unit.
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Model E8 Series Operation Manual
E8 Series GPS Timing & Frequency Reference
Introduction
The GPS clock is shipped ready for operation. No adjustments are needed to have a 10MHz
frequency reference and 1 pulse per second time reference within 20 minutes of initial switch on.
The status of the GPS lock is shown on four LEDs on the front panel.
For more information as to satellite signal strengths, etc, a computer with RS232 may be connected
to the interface. A freeware program such as WinOncore may be used to display information from
the GPS receiver.
Installation
The antenna should be installed, preferably with a 360 degree view of the sky. However the receiver
is very sensitive and will give good results with the antenna on a window ledge, or even inside a
building. The satellite signal strengths may be checked after installation using a computer with
suitable software connected to the RS232 interface. The DC power supply should be connected. The
unit will operate with any voltage between 6 and 15V DC. Current consumption for the E8-X is
about 250mA max and the E8-Y about 300mA continuous, 500mA maximum warm up. A universal
line power supply is provided.
Operation
The unit is fully programmed to operate without adjustment anywhere in the world. The GPS
receiver will take about 1 minute to obtain a fix from a cold start with unknown location. The
receiver then does a "site survey" for about 15 minutes, averaging the positions obtained. After the
site survey is complete, the receiver switches to position hold mode, and uses all the satellites
available to improve the accuracy of the time calculation. At this point the unit will lock its 20MHz
reference oscillator to the GPS signal. This only takes a few seconds. When the PLL locks the red
"lock" LED should go out, but may flash for a further minute as the PLL settles. The normal
operating condition is with the red "lock" LED off.
The status of the satellite tracking is shown by the green and amber LEDs. The normal situation is
that the green LED shows a long flash, followed by a number of short flashes. The number of short
flashes shows the number of satellites being tracked, and included in the time solution. The amber
LED may also flash. This shows the number of satellites being tracked, but not included in the
timing solution.
If the red "lock" LED should start to flash at about 1Hz rate, this indicates that the phase error
between the GPS signal and the internal 20MHz oscillator is greater than a pre programmed
threshold. This does not indicate that the 10MHz output is unlocked. During normal operation the
GPS receiver estimates the accuracy of the timing solution using the "TRAIM" algorithm (Time
Receiver Autonomous Integrity Monitoring) developed for the Motorola Oncore receiver. If the
predicted timing error is greater than the programmed limit, the receiver will switch into standby,
and the red lock LED will turn on. The 10MHz output and 1pps output will then drift according to
the ambient temperature and aging of the internal oscillator. The unit should never go into standby
during normal operation. The most likely reason for doing so is a major antenna fault.
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Model E8 Series Operation Manual
Interface and programming
The unit has one RS232 compatible interface. This is shared between the GPS receiver and the
microcontroller that locks the 10MHz output to the GPS signal. On Initial switch on the interface is
connected to the microcontroller. If no valid interface code is received within 30 seconds, the
interface switches over to the GPS receiver. If a valid interface code is received, the interface
remains connected to the microcontroller until the next power on reset.
GPS interface
The GPS receiver interface uses Motorola binary format. In order to use this, a freeware program
such as WinOncore should be installed on the user’s PC.
Connect the unit to the PC and start the program. It may be necessary to set the port and baud rate
(9600). The receiver is preset to output 3 sentences on a continuous basis. These are Ha,
(position/status/data), Hn, (12 channel TRAIM status message) and Bb (Visible satellites).
The various windows available from the program should show current satellite data, etc.
It is important to note that some parameters shown by the program will not correctly indicate the
actual state of the receiver. This is because the program does not automatically update its
information when started. In particular, the TRAIM algorithm will be shown as off when in fact it is
by default on in the receiver.
For the receiver to operate correctly, the site survey must be enabled, and the TRAIM must be on. If
this is not the case, the receiver will track satellites and compute a fix, but the red lock LED will not
go out, showing the 10MHz output is in the standby state.
If the receiver gets stuck in a state where it does not lock, the user may inadvertently disabled the
TRAIM or the site survey. To get back to a known state, the following should be performed:
The messages can be sent using the message window in the WinOncore software.
Return to factory default state:
"@@Cf"
Enable Position Auto-survey; consult the CW12 user manual for further details
"@@Gd03"
Enable T-RAIM algorithm; consult the CW12 user manual for further details.
- "@@Ge01"
Set the alarm threshold for the T-RAIM algorithm (300ns). See the CW12 user manual for further
details
"@@Gf300"
Request channel T-RAIM status message (sent every second)
"@@Hn01"
If required, the position/status/data message may be turned on:
"@@Ha01"
If required, the visible satellites message may be switched on:
"@@Bb01"
The GPS receiver stores the current status in non volatile memory when switched off.
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Model E8 Series Operation Manual
Microcontroller Interface
The microcontroller interface allows setup and debug of the digital phase lock loop which locks the
20MHz reference oscillator to the GPS receiver. The list of control codes is given in an appendix.
The only user adjustable parameter is the PLL bandwidth, which is accessed with command "UA".
The band width has been factory set to optimum for the E8-X (TCXO) and the E8-Y (OCXO). It is
only recommended that the user adjusts these values if he is able to measure Allen variance of the
10MHz output at averaging times between 1 and 1000 seconds.
"UA?" will return the current bandwidth (0 to 7, with 0 the narrowest bandwidth)
The second parameter (hex) is the elapsed running time in units of 2.33 hours.
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Model E8 Series Operation Manual
Specifications
OUTPUTS:
Sine wave, 10MHz, 12dBm ± 2dBm into 50ohms
Harmonics
< -50dBc
Spurii
<-75dBc
TTL, 3.3VCMOS, 1pulse per second
POWER SUPPLY:
6 to 15V DC 250mA – 500mA
DPLL tracking bandwidths
5mHz to 500mHz typical in 8 binary increments
Default 20mHz
LOCK INDICATOR
On
not locked
Off
locked, low phase error
Short flash every second:
locked, high phase error
GPS INDICATOR
Green: indicates no of satellites used in time solution
Amber: indicates no of satellites tracked but not used in time solution
INTERFACE
Shared between DPLL and GPS receiver
DPLL
9.6kbaud, RS232, PC compatible
GPS
9.6kbaud, Motorola binary format
(8bits no parity, no handshake)
INTERFACE CODES
See Appendix B
TIME DOMAIN STABILITY
(10MHz output)
Tau
Allen variance
1s
10s
100s
1000s
>10000s
E8-X
<2x10-10
<4x10-10
<5x10-11
<1x10-11
<5x10-12
JITTER
(1PPS output)
Typical < 5ns RMS
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Model E8 Series Operation Manual
Phase Noise
E8-X
1Hz
10Hz
100Hz
1 kHz
10 kHz
-60dBc
-90dBc
-115dBc
-130dBc
-140dBc
WARMUP
< 15 minutes to specified accuracy
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Model E8 Series Operation Manual
Appendix A
Board set up
Links
SP1 Leave open circuit, Used to upload new firmware to the CW25 GPS module.
SP2 Leave open circuit for 3.3V antenna power. Link (default) for 5V antenna power.
SP3 Link only when external clock version of the CW25 is used.
SP4 Leave open circuit when U5 (enhanced voltage reference) is used. Link when U5 is not fitted to
board.
JP1 & JP3 fit both jumpers with shorting links for normal operation. Links must be removed when
programming U3 from the Microchip ICD-2 programmer. U3 should be powered from the
programmer when programming. This is necessary as U3 cannot be programmed with 3.3V Vdd.
U5 May be omitted when TCXO reference is used.
U16 MUST be omitted when internal clock version of the CW25 is used. It must be fitted when the
external clock version of the CW25 is used.
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Model E8 Series Operation Manual
Appendix B
RS232 control codes
(all values following command or returned from the microcontroller are hexadecimal)
* = backed up in EEPROM
UA
User adjust
UA?
Returns user parameters aa bbbb
*
aa
is bandwidth control: bits set:
*
bbbb
is clock registers 3 and 4 (elapsed time)
UABaa
OS
bit0, 1, 2: bandwidth (0 to 7)
Write new bandwidth control byte
Overall Status
OS?
Returns overall status bytes: aa bb cccc
aa
is test status byte:
Bits set: bit0, 1, 2:
bit3:
bit4:
bit5:
bit6:
bit7:
Bits 2, 1, 0:
bb
cccc
000
001
010
011
100
101
110
111
is lock status byte:
Bits set bit0 to 2:
bit3:
bit4:
bit5:
bit6:
bit7:
is PLL control:
Bits set bit0, 1, 2, 3
bit4, 5, 6, 7
bit8, 9, 10, 11
bit12, 13, 14, 15
bits 0 to 2 DAC output select
no integrator update
no proportional term
Inhibit holdover mode
NU
inhibit state control
no test output, fine tune DAC used for tuning
sub sampled I
sub sampled Q
PLL Integrator upper 16 bits
Phase result
I sample (filtered)
Q sample (filtered)
references CH6 (filtered)
State control, states 0 to 7
set to normalise tuning DACs (cleared automatically)
NU
Loop locked
narrow range phase detector in use
set to inhibit auto load of PLL gain parameters
subsample rate
exp filter order
integrator gain
proportional gain
OSTaa
Write new test status byte
OSLbb
Write new lock status byte
OSGcccc
Write new PLL control
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Model E8 Series Operation Manual
PL
Phase lock loop
PL?
Returns current status of PLL
aaaa bbbb cccccccc dddd eeee
*
PD
aaaa
bbbb
cccccccc
dddd
eeee
last value of I sample (filtered), 2s complement, 16 bit
last value of Q sample (filtered), 2s complement 16 bit
last value of PLL integrator (32 bit integer)
Coarse tune DAC 16 bit integer
Fine tune DAC 16 bit integer
PLIcccccccc
Write new PLL integrator
PLCdddd
Write new coarse tune DAC
PLFeeee
Write new fine tune DAC
PL+
Enter command PL? into repeat stack
Phase detector
PD?
Returns phase detector parameters
aaaa bbbb cccc dddd eeee
aaaa
bbbb
cccc
dddd
eeee
PD+
Last phase result, 2s complement
Last mod[I] +mod[Q]
2.5V reference (filtered)
mod (phase result) (filtered) lsb=3.05ps
mod(freq offset) (filtered) lsb = 2.33E-14
Write PD? to command repeat stack
EU
EEPROM
Update (backed up values)
SR
ER
Software Reset
EEPROM read
ERCaabb
Returns bb bytes from starting address aa as ASCII characters
ERNaabb
EW
Returns bb bytes from starting address aa as hexadecimal numbers (character
pairs)
EEPROM write
EWCaabbccccc------c
Writes bb characters to starting address aa. Correct number of characters must be included in string
EWNaabbcccc------c
Writes bb bytes to starting address aa. Character pairs cc etc. are interpreted as hexadecimal
numbers.
RI
Repeat Interval
RI?
Returns command repeat interval
aa
aa
8 bit command repeat interval multiplier. Range 1 to 255. Command repeat interval is 50ms x
aa
RI0aa
Write new command repeat interval
RID
Cancel command repeat and clear command repeat stack
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