PC Time and Frequency Processors Models bc620/627AT � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � Features PC, XT or AT Bus Operation (ISA/EISA Compatible) GPS or Time Code Inputs Time Code Output Pulse Rate Outputs � Applications Frequency Outputs (1, 5, or 10 MHz) � External Event Capture/Interrupt � Programmable Periodic Output/Interrupt � Programmable Time Strobe Output/Interrupt Suplied with FREE MS DOS Device Driver � � � � Overview � The Datum bc620/627AT Time and Frequency Processor modules provide precision Data Acquisition � time and frequency reference to the host computer and peripheral data acquisition � systems. Time is acquired from either the GPS satellites using a supplied antenna/ receiver (bc627AT only) or from time code signals, typically IRIG B. Integration of the � module is facilitated with a driver for MS DOS that is included at no cost. Optional � Software Development Kits are available for Windows 95 and Windows NT. � � Central to the operation of the module is a disciplined 10 MHz oscillator and � 100 nanosecond clock. Current time (days to 100 nanoseconds) can be accessed across the bus with zero latency, which allows for very high speed time requests. The � oscillator is rate-matched (disciplined) to the input time source and drives the precision Test Ranges � 10 MHz frequency output and time code generator circuitry. If the time source is lost, � the module will continue to maintain time (flywheel). � Both time code generation and translation are supported. The generator supplies � IRIG B time code output synchronized to the input time source. The translator decodes � either IRIG A, IRIG B, 2137, XR3 or NASA 36 time code inputs. � � An Event Time Capture feature provides a means of latching time for an event input. � The module can also be programmed to generate a periodic pulse rate interrupt as well as to generate a single time strobe at a predetermined time. Computer � Synchronization � PC Time and Frequency Processors Models bc620/627AT � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � AT Bus Specifications Address Space 1 Block of 16 Bytes in the PC I/O Real Time Clock Map Range 100H - 3FFH Bus Request Resolution 100 nanoseconds Data Transfer 8-bit Latency Zero Interrupt Levels IRQ 3-7, 9-12, 14-15 Major Time Format Binary or BCD (jumper selected) Minor Time Format Binary Power +5 VDC @ 450 mA +12 VDC @ 55 mA (bc620AT) Time Code Translator +12 VDC @ 250 mA (bc627AT) Time Code Formats IRIG B, NASA 36, XR3, 2137 -12 VDC @ 20 mA (modulated or DCLS) Modulation Ratio 3:1 to 6:1 GPS Subsystem (bc627AT only) Input Amplitude 500 mV to 5 V P-P Time Accuracy <–2 microseconds Input Impedance >10KW (AC coupled) Position Accuracy 100 meters SEP (SA on) Carrier Frequency –50 PPM (max) Maximum Velocity 300 meters/sec (1,080 KPH) Number of Channels 6 Time Code Generator Receiver Frequency 1.575 GHz (L1, C/A code) Time Code Format IRIG B Time to First Fix Brief power off: 1.5 min (1-4 SV) Modulation Ratio 3:1 Worst case: 5 to 15 min Output Amplitude 1 V to 10 V P-P (adjustable) Solution Modes 1,3, and 4 satellites DC Level Shift TTL/CMOS Environment Timing Functions Module Antenna/Receiver Heartbeat (TTL, 50W) Programmable periodic Operating Temperature 0C to 55C -30C to 70C 2.3 mHz to 2.5 MHz Storage Temperature -50C to 100C -55C to 100C (adjustable pulse width) Operating Humidity 10% to 80% 100% Time Strobe (TTL, 50W) Programmable, 1 mS through Storage Humidity 5% to 95% 100% hours (1 mS pulse width) 1 PPS Output (TTL, 50W) 200 mS pulse width Connector Types Event Capture Input 100 nS resolution, zero latency J1 - Module I/O Signals 15-pin �DS� (20 nS min pulse width; 250 nS J2 - GPS Interface 15-pin high-density �DP� (bc627AT) min period) Software Support Disciplined Oscillator �C� Demo Program Free, supplied on diskette Frequency 10 MHz MS DOS Device Driver Free, supplied on diskette Outputs 1, 5, or 10 MHz (selectable) Rate Accuracy: Options -8 Standard VCXO 5X10 short term (tracking) IRIG A Decoding -7 5X10 long term (flywheeling) ACUTIME GPS Firmware** -9 Optional Oven Oscillator 2X10 short term (tracking) ACUTIME Antenna/Receiver** -8 5X10 long term (flywheeling) Airborne GPS Receiver Sync Sources GPS, Time Code, 1 PPS Magnetic GPS Antenna External GPS Receiver (SV6) External Time Base Frequency Input Extended Length GPS Antenna Cable 10 MHz Square Wave TTL (45-55% duty cycle) Isolation Transformer Time Code Input 10 MHz Sine Wave 0.5 to 4.0 V P-P Ovenized Crystal Oscillator �D� Connector (J1) to BNC Adapter WINSDK for Windows 95 and Windows NT **part of upgrade from bc620AT to bc627AT � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � Datum-San Jose For more information about the complete range 6781 Via Del Oro of Quality Timing Products from the Datum San Jose CA 95119-1360 Group of Companies, call (800) 348-0648 in Toll Free (800) 348-0648 the United States and Canada. Telephone (408) 578-4161 Fax (408) 574-4950 Or visit our site on the World Wide Web at e-mail salessj@datum.com http://www.datum.com for continuously updated specifications and information. Specifications are subject to change without notice. Copyrightª Datum Inc. All rights reserved. BD9802007B