�����$ GPS Time and Frequency Reference Receiver Symmetricom’s 58540A GPS time and frequency reference receiver features: • Eight-channel, parallel tracking GPS engine • C/A Code, L1 Carrier • GPS T-RAIM satellite error detection • +24 Vdc power operation • SCPI Command set -11 • ≤ 1×10 frequency accuracy when locked to GPS -10 • ≤ 7×10 per day average frequency change when not locked to GPS • ≤ 110 ns time accuracy with respect to UTC (USNO MC) • Compatible with 58531A GPS timing receiver analysis and control software The 58540A is a cost-effective source of highly accurate time and frequency signals referenced to the global positioning system (GPS). Designed to be easily integrated into system equipment to meet the needs of a variety of applications including base station synchronization and E-911 wireless location, the 58540A is a compact unit that requires only 10 watts of power after warmup. All connections to the parent system are easily accessible from the front panel. The 58540A is also suitable for use in laboratories and manufacturing facilities when low-cost precision and synchronized timing references are required. To meet the evolving demand for smaller wireless and telecom equipment, the 58540A is packaged in an extremely compact box. With a size of only 50 mm H × 100 mm W × 125 mm L, and a weight of 450 grams, the box can be easily and conveniently mounted to an existing PC board, to a system rack or in an electronics enclosure. An RS-232C serial port provides the system-level interface. Through the use of the Standard Commands for Programmable Instruments (SCPI) command set or the 58531A GPS timing receiver analysis and control software (described on page 4), you can monitor the 58540A’s operation. The product also features a number of GPS satellite health monitoring and reporting functions. One of the many features offered in the 58540A is the Time Receiver Autonomous Integrity Monitor (T-RAIM) algorithm, which ensures that corrupt satellite data is ignored so it has no affect on the 58540A’s timing accuracy. Standard Configuration: 10 MHz and 1 PPS In its standard configuration, the 58540A produces a 10 MHz and a one-pulse-per-second (1PPS) timing output. Phase coherency is maintained between the frequency and timing outputs — a feature essential in many timing applications. When the crystal oscillator is locked to the GPS signal, the frequency accuracy of the 10 MHz -11 signal is better than 1x10 for a one-day average, and the 1PPS signal is synchronized to universal coordinated time, UTC (USNO MC) within 110 ns rms (95% probability). Figure 1. 58540A as viewed without cover. 58540A GPS Time and Frequency Reference Receiver 2 Other Configurations Custom Symmetricom may be able to customize the 58540A to your specifications, depending on volume and the complexity of the modification. Contact your local Symmetricom representative to discuss your specific needs. Stanard Optionds Option 001 with the 58540A transforms the RS-232C serial port from the standard DTE configuration into the DCE configuration. In addition, Option 001 provides an antenna connector of Type-F (female) instead of the standard connector which is TNC. Option 002 provides one pulse every other second (1PP2S), synchronized to the even seconds in GPS time, in place of the standard 1PPS output. The one-pulse-every-other-second signal, otherwise known as the even-second pulse, is the reference time used in CDMA base stations. Antenna and Accessories Symmetricom recommends the use of GPS antenna system accessories with the 58540A to ensure specified performance. Symmetricom offers a complete line of low-cost, durable, easy-to-install GPS accessories. These include the 58532A GPS L1 reference antenna, and the 58538A and 58539A lightning arrestors. Also available is the 58529A line amplifier with L1 bandpass filter which provides the gain to overcome cable loss as well as protection against noise and interfering signals. For systems needing protection from noise and interfering signals but not GPS signal gain, choose the 58530A GPS L1 bandpass filter. Other accessories include a selection of RF cables, and a family of active GPS L1 signal splitters to allow more than one receiver to be connected to an antenna. The 58535A 1:2 GPS L1 distribution amplifier allows 2 receivers to share one antenna. The 58536A 1:4 GPS L1 distribution amplifier allows 4 receivers to share one antenna. Symmetricom GPS antenna system accessories are sold separately from the 58540A. Symmetricom 3 58531A GPS timing receiver analysis and control software Version 1.2. Evaluation of the 58540A is made easy with version 1.2 of the 58531A GPS timing receiver ® analysis and control software. The PC Windows based program (for Windows NT or Windows 95) interfaces with the 58540A, and processes and displays information received from it. The program has tools to help in analyzing the receiver data, and can log the information to a file for analysis using other tools. The 58531A program includes these features: • Conveniently configure the software and 58540A • Receive real-time information updates • Control and query the 58540A via menu-driven commands • Generate a data log file for analysis • Generate an error log file for analysis • Plot instant or average position in real-time • Plot satellite history, such as signal strength (C/N), elevation, and dilution of precision (DOP) • Calculate and display average or maximum C/N and associated elevation and azimuth angles Version 1.2 is compatible with the 58540A and 58533A GPS receivers and the 58534A GPS timing antenna. 58531A software is sold separately from the GPS receivers. Specifications and Characteristics of the 58540A GPS Time and Frequency Reference Receiver 10 MHz Sine We Oututavp (lock tedo GPS) -11 Frequency Accuracy ≤ 1 x 10 for a one day average. Locked to GPS. Output Level 13 dBm ± 2 dB. Into 50Ω load. -10 Time Domain Stability Root Allan Variance ≤ 5 x 10 for a one Locked to GPS. second averaging time. See Note 1. Frequency Domain Stability (Phase Noise): ≤ -120 dBc/Hz @ 10 Hz from carrier ≤ -130 dBc/Hz @ 100 Hz from carrier ≤ -140 dBc/Hz @ 1 kHz from carrier ≤ -145 dBc/Hz @ 10 kHz from carrier ≤ -145 dBc/Hz @ 100 kHz from carrier Harmonics ≤ -30 dBc. Spurious < -80 dBc from 0 to 2 GHz Oscillator Performance: -10 Aging ≤ 7 × 10 per day average frequency Not locked to GPS. change, typical. -8 Temperature Stability ≤ 2 × 10 , typical. 0° to +55° C Not locked to GPS. 58540A GPS Time and Frequency Reference Receiver 4 1PPStt Oupu Frequency 1 pulse per second Output always. Time Accuracy (absolute) ≤ 110 ns with respect to UTC (USNO MC) –95% See Note 1. probability when unit is properly installed, calibrated and locked to GPS. Time Accuracy (relative) ≤ 30 nsec with respect to like-kind 58540A receivers, for a one day average, typical. Units must be receiving the same satellites. Pulse-to-Pulse Jitter of leading edge ≤ 25 nsec rms, typical Holdover ≤ 100 μsec accumulated time error after 1 hour Not locked to GPS. of unlocked operation. See Note 2. Output level ≥ 2.4 V, TTL compatible Into 50Ω load. Polarity Positive Pulse Time Mark Rising Edge of Pulse Pulse Width 20 μsec, nominal Rise Time ≤ 5 nsec 10% to 90%, 50Ω load Fall Time ≤ 5 nsec 10% to 90%, 50Ω load 1PPS/10 MHz Synchronism The 1PPS rising edge and the positive going zero Locked to GPS. crossings of the 10 MHz reference are coincident within ±3 nsec. Option 001 The 1PPS rising edge is 8 nsec ±3 nsec after the Locked to GPS. positive going zero crossings of the 10 MHz reference. Input Power Operating Voltage +24 Vdc, nominal Range +18 to +32 Vdc Power Consumption: Warm Up ≤ 15 W ≤ 10 W Steady State Damage Level + 60 Vdc max. Environmental Operating Temperature 0°C to +55°C See Note 3. Storage Temperature -40°C to +85°C Operating Humidity 10% to 95%, non-condensing Note 1. Achieved one hour after initial GPS satellite lock. 2. This specification is based on the availability of 4 or more GPS satellites during 2 days of locked operation with a fixed antenna location. 3. Maximum rate of change is 5° C per hour. Symmetricom 5 Signal and Power Connections DESIGNATION FUNCTION/PIN ASSIGNMENT CONNECTOR TYPE COMMENTS RS-232C Data Bus Serial datacomm for control and DB-9, female Serial protocol is SCPI. Time status inquiry. Standard Config- code output is available to a uration (DTE): Pin assignment: computer immediately preced- ing the 1PPS signal for the 1. N/C current second. 2. RxD Factory defaults: baud rate 3. TxD 9600, 8 data bits, 1 start bit, stop 4. Alarm bit, no parity. 5. GND 6. External Reset 7. N/C 8. N/C 9. N/C Option 001 Configuration (DCE): 1. N/C 2. TxD 3. RxD 4. Alarm 5. GND 6. External Reset 7. N/C 8. N/C 9. N/C Input from GPS Antenna Standard: TNC, Female Option Power supplied to antenna: 001: Type F, Female 5V ± 10% at 50 mA. 10 MHz Output 10 MHz Output Connector BNC, Female 1PPS Output 1PPS BNC, Female Output Connector Input Power Pin 1: 24 Vdc Pin Amp-Mate-N-Lok Mating Connector is Pin 2: NC Pin Female AMP 350766-1 (male shell). Pin 3: 24 V return (Type 643228-1) Pins are AMP 350690-1. 58540A GPS Time and Frequency Reference Receiver 6 Alarm LED Description The Alarm LED is off when no power is applied to the unit. It remains off for one second after power is applied while the unit performs an internal self-test. On initial power-on, the LED will be red due to lack of GPS satellite data (receiver alarm). The Alarm LED illuminates green when there are no alarms. The Alarm LED illuminates red for any one of the status conditions listed in the table below: STATUS DESCRIPTION Antenna Alarm Antenna current is less than 5 mA (open) or greater than 50 mA (short) Receiver Alarm Insufficient satellite data for positioning. Holdover Receiver is in alarm mode, or is forced into holdover mode via the appropriate command. PLL Abnormal Hardware detects a phase drift between OCXO and reference. D/A Converter The value set by the D/A converter is out of range Setting Out of Range 1PPS Abnormal Hardware detects an abnormal 1PPS output. 10 MHz Abnormal Hardware detects an abnormal 10 MHz output. ROM Error The ROM checksum test failed. RAM Error The write/verify RAM test failed. NVRAM Error NVRAM test failed. Note 1. Mounting holes are on the underside of the 58540A. Maximum length of mounting screws is 15 mm. Symmetricom 7 For more information: Dependable Accessories for your GPS Installation—Brochure Designing Your GPS Antenna System—Configuration Guide ©2000 Symmetricom Specifications subject to change without notice. DS/58540A/D/0300/2M 0 1 1 1 1 0 1 1 1 0 1 1 0 1 0 0 1 0 0 0 1 0 0 0 1 1 1 1 0 0 1 0 1 0 0 0 1 1