Dewesoft Ds-gps-clock Product manual

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DS-GPS-CLOCK

TECHNICAL REFERENCE MANUAL

DS-GPS-CLOCK V20-2

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DS-GPS-CLOCK
TECHNICAL REFERENCE MANUAL
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Table of contents
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Table of contents 2
About this document 4
1. Legend 4
Specifications 5
1. Shock & Vibration 6
Device overview 7
1. GPS based operation 8
2. IRIG based operation 8
3. LED Description 8
3.1. Power 8
3.2. Status 9
4. Mounting the aerial 9
5. Warm-Up time 9
6. Scope of supply 10
7. Connection 11
7.1. Front Connectors 11
7.1.1. LEDs 11
7.1.2 Aerial connector 11
7.1.3 IRIG connector 12
7.2. Rear Connectors 12
7.2.1. Multi I/O Connector 13
7.2.2. Mini USB connector 14
7.2.3. SYNC connector 14
8. Installation 15
9. Connecting the DS-GPS-CLOCK to the DAQ-System 15
9.1. Synchronization to system with Clock and Trigger 15
10. Configuration of DewesoftX® for the DS-GPS-CLOCK 15
10.1. Update rate 16
10.2. Maps directories 16
10.3. Timing settings 16
10.3.1. Input settings 18
11. Channel setup 19
12. Measurement setup 20
13. Time code restore 20
Warranty information 23
1. Calibration 23
2. Support 23
3. Service/repair 23
4. Restricted Rights 24
DS-GPS-CLOCK V20-2 2/28 

DS-GPS-CLOCK
TECHNICAL REFERENCE MANUAL
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5.5. Printing History 24
5.6. Copyright 24
5.7. Trademarks 24
6. Safety instructions 24
6.1. Safety symbols in the manual 24
6.2. General Safety Instructions 24
6.2.1. Environmental Considerations 25
6.2.2. Product End-of-Life Handling 25
6.2.3. System and Components Recycling 25
6.2.4. General safety and hazard warnings for all Dewesoft systems 25
7. Version History 28
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DS-GPS-CLOCK V20-2 3/28 

DS-GPS-CLOCK

TECHNICAL REFERENCE MANUAL

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2. About this document

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2.1. Legend

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The following symbols and formats will be used throughout the document.

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Important

It gives you important information about the subject.

Please read carefully!

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Hint

It gives you a hint or provides additional information about a subject.

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Example

Gives you an example of a specific subject.

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DS-GPS-CLOCK V20-2 4/28 

DS-GPS-CLOCK

TECHNICAL REFERENCE MANUAL

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3. Specifications

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DS-GPS-CLOCK V20-2 5/28 

IRIG Input Specifications

Supported codes

IRIG code A or B / AM or DC

Compatibility (AM code)

0.5 Vpp to 10 Vpp

Ratio (AM)

3:1 ±10 %

Compatibility (DC code)

DC Level Shift TTL / CMOS compatible

Impedance

20 kΩ

Isolation

150 VDC

Trigger accuracy

1 µsec

IRIG output specifications

Supported codes

IRIG code B, DC

Isolation

None

Accuracy

< 1 µsec (delay to GPS PPS)

GPS specifications

General

12 channel, L1 frequency receiver

PPS accuracy

100 ns

Refresh rate

1 Hz

Position accuracy

Horizontal CEP

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Autonomous

3.0 m

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Differential

1.0 m

Trigger accuracy

1 µsec

System specifications

Clock accuracy locked

without drift

Clock accuracy unlocked

< 10 ppm

Input

SMA for GPS antenna, BNC for IRIG I/O

DS-GPS-CLOCK

TECHNICAL REFERENCE MANUAL

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3.1. Shock & Vibration

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DS-GPS-CLOCK V20-2 6/28 

Output: Trigger:

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Clock and Trigger for DAQ-systems on DB9 connector

PPS (pulse per second), rising edge on time, 75 msec high

time, TTL level compatible 10 Hz to 10 MHz, rising edge

synchronized, 50 % duty cycle, TTL level compatible.

Power supply

USB powered, max. current 500 mA

Environmental specifications

Operation temperature

-5 °C to +70 °C

Storage temperature

-20 °C to +85 °C

Humidity

10 % to 80 %; non condensing

Dimensions (W x D x H)

133 x 104 x 43 mm (5.23 x 4.1 x 1.7 in.)

Weight

approx. 330 g (0.72 lb)

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Vibration Tests

Shock Test

European Standard

EN 600068-2-6

EN 60721-3-2 Class 2M2

EN 60068-2-27

Shape

Sine

Random

Half-sine

Frequency

0 Hz to 150 Hz

10 - 200 Hz

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Power spectral density

1 m/s² / Hz from 10 – 200 Hz

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Acceleration amplitude

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15 g

Duration

30 Minutes per axis

11 ms

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Test in 3 axis, 3 shocks in each axis and direction

DS-GPS-CLOCK

TECHNICAL REFERENCE MANUAL

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4. Device overview

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The DS-GPS-CLOCK is a synchronized time base generator capable of using either GPS or IRIG as a time                 

source. This allows completely synchronized data acquisition of multiple systems whether they are            

mobile or stationary. Additionally, the DS-GPS-CLOCK can also be used as an IRIG time code generator               

(output IRIG B/DC) synchronized to the GPS time.

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The diagram below outlines the basic functionality of the DS-GPS-CLOCK:

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Image 1: Block Diagram

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DS-GPS-CLOCK

TECHNICAL REFERENCE MANUAL

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4.1. GPS based operation

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The base of any GPS receiver is precise time measurement. In addition to the position information a                

precise PPS (pulse per second) is generated by the GPS engine. This pulse is used to synchronize a 40                  

MHz oscillator with software PLL (phase locked loop). The result is an ultra-stable 40 MHz clock source                

which is completely free of drift over time.

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Out of this 40 MHz base clock, the programmable clock divider generates the clock frequency for the                

standard data acquisition system which is being output on the 9-pin DSUB connector or 4-pin Lemo               

connector.

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4.2. IRIG based operation

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The IRIG signal contains the binary-coded time (year, day of year, hours, minutes, seconds, fractions of a                

second) modulated on a sine wave carrier. This signal is decoded to the PPS and the drift-free 40 MHz                  

clock.

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The following IRIG time codes are supported:

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●IRIG-A (10 Hz)

●IRIG-B (1 Hz)

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4.3. LED Description

4.3.1. Power

The power LED is solid green when the DS-GPS-CLOCK is in normal operation.

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Image 2: LED lights

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DS-GPS-CLOCK V20-2 8/28 

DS-GPS-CLOCK

TECHNICAL REFERENCE MANUAL

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4.3.2. Status

The status LED indicates the current status of the device:

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4.4. Mounting the aerial

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The aerial supplied with the DS-GPS-CLOCK is designed to be mounted magnetically on any metallic              

surface. The cable length is 5 m.

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Please contact your sales manager if your application requires a different aerial.

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4.5. Warm-Up time

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When the DS-GPS-CLOCK is used as a GPS based time code generator for the first time, has been                 

moved more than 200 km, or not used for 10 hours (since last usage), it is recommended to perform a                   

‘cold start’. To get the best performance from your GPS in the future, perform this cold start in an open                   

place with a good all round view to the sky. Allow the GPS to map the satellites for at least 20 to 30                      

minutes. The GPS builds up the ‘Ephemeris’ data on each satellite which is stored in a non-volatile                

memory so that future satellite tracking is swift and stable. Once the GPS has carried out a successful                 

cold start, future satellite lock from power up will take between 15 seconds and 1 minute. Before going to                  

test in a shady environment with tall objects or near to trees, allow the GPS to settle in an open space for                     

5 to 10 minutes.

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DS-GPS-CLOCK V20-2 9/28 

At normal operation - when DS-GPS-CLOCK is

locked to the selected time source - it shortly

blinks once a second.

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Image 3: LED: Normal Operation

When the time source signal is missing (neither

GPS or IRIG time code signal), the device

automatically goes to flying-wheel operation. This