Model 1088B GPS Satellite Clock (40 ns)

Model 1088B GPS Satellite Clock (40 ns)

Setting the standard by which other precision time clocks are measured, Model 1088B features unprecedented accuracy, maximum flexibility and proven reliability.


Model 1088B User Manual
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Model 1088B Quick Setup Guide
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Model 1088B User Manual Español
Download PDF(1 MB) »

Model 1088B Data Sheet
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Model 1088B Data Sheet Español
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GPS Antenna Data Sheet
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Leading the precision time clock industry, Arbiter's top-of-the-line Model 1088B offers unprecedented accuracy, flexibility, and reliability for applications in precision timing.

Model 1088B delivers GPS timing accuracy of 100 ns rms from UTC/USNO. Typical performance is less than 40 ns RMS. Need complete resistance to loss of GPS synchronization? The 1088B supports an interconnection to a second 1088B providing fail-safe redundancy.

If your application demands maximum versatility, look no further than the 1088B. Standard input/output (I/O) capabilities provide over 260,000 possible configurations, with 22 available signals. Featuring a second option board slot found only on the 1088B, the number of configurable options grows even further. Options include an internal Network Time Protocol (NTP), four configurable fiber optic outputs, COMTRADE Sample Rate Generator, Power System Time, Frequency and Phase Monitor, a second RS-232 port and more.

  • More configuration options than any other clock
  • Highest accuracy, < ± 40 ns RMS typical; < ± 100 ns worst case
  • Four user configurable BNC connectors supporting multiple output functions including IRIG-B modulated, 1 PPS, Programmable Pulse, IRIG-B Modified Manchester (IEEE 1344) and more.
  • Fiber Optic support
  • NTP compatible
  • Two Form C (SPDT) fail-safe relays, locked and jumper selectable
  • Two Event Inputs (Channel A and B) included
  • IEEE C37.118 compliant for Synchrophasor use.

Receiver Characteristics

Timing Accuracy

Accuracy Note

Specifications apply at the 1 PPS output, in the presence of Selective Availability (SA), as of date of publication.

Accuracy UTC/USNO
  • UTC/USNO ± 50 ns rms, when receiving 4 or more satellites and Position-Hold Mode on
  • UTC/USNO ± 100 ns rms, receiving a single satellite and Position-Hold Mode on
  • UTC/USNO ± 200 ns rms, when receiving 4 or more satellites and Position-Hold Mode off


  • CMOS output signals are synchronized to the 1 PPS output, ± 50 ns, maximum.
  • IRIG-B modulated, ± 1 us, maximum
  • The leading edge of the start bit of a received RS-232 data message may be selected to trigger the Event a input, providing synchronization with 100 ns resolution.

Position Accuracy

10 meters, rms, 90 % confidence

Satellite Tracking

Twelve (12) channel, C/A code (1575.42 MHz). Receiver simultaneously tracks up to twelve satellites. Results from all tracked satellites are averaged in Position-Hold Mode or, with Position-Hold Mode off, using least-squares estimation.


  • 150 seconds typical, cold start
  • 15 minutes, 90 % confidence, cold start
  • 40 seconds, with almanac less than 1 month old
  • 15 seconds, with ephemeris less than 4 hours old
  • The GPS Data Backup Battery is included in the Model 1088B. This feature improves acquisition time by supplying constant power to the real-time clock and RAM in the GPS receiver module.

I/O Configuration

Output Connectors

  • Four, BNC, user-configurable. Each connector is configurable as a specific input function or as any one of 22 output functions, listed below, by means of internal, push-on jumpers. Each output connector is independently buffered. Configuration is easily changed in the field. Refer to the options section for more outputs.
  • Analog outputs are op-amp (LF353) followers with 560-ohm protective resistors.
  • CMOS outputs are buffer type (74HC126) with 47-ohm source resistors.

Output Signals


  • IRIG-B, 1 kHz modulated, 10 Vp-p
  • 1 PPS deviation; ± 5 V at 10 µs/V


  • IRIG-B, IRIG-E, IRIG-D, or IRIG-H, level-shift
  • 1 PPS, 1 PPM, 1 PPH
  • 1 PPS, 10 PPS, 50 PPS, 60 PPS, or 100 PPS
  • 1 kPPS, 10 kPPS, or 100 kPPS
  • 1 MPPS, 5 MPPS, or 10 MPPS
  • Locked
  • Programmable Pulse
  • IRIG-B Modified Manchester (IEEE Standard 1344)

Event Inputs

Two inputs are available, each having a 100 ns timing resolution. Each input may be configured to accept an external 1 PPS signal, and measure the deviation from 1 PPS/GPS or to record up to 300 sequential events (separated by 11 ms). Event data is logged in battery-backed RAM and may be read or cleared from the front panel or RS-232 interface.

Programmable Pulse Output

Four modes:

  • Every 1 second to 60,000 seconds, starts top of the minute
  • Hourly at a specified offset
  • Daily at a specified time of day
  • One-shot at a specified time of year

Pulse duration is programmable from 0.01 seconds to 600 seconds, except in one-shot mode, where the output is Low prior to the specified time and High thereafter.

Input Functions

Channel A

Event or 1 PPS: 5 V TTL/CMOS level

Channel B

Event or 1 PPS: 5 V TTL/CMOS level

Freq. Reference

5 V TTL/CMOS or AC-coupled; 100 kHz, 1 Mhz, 5 MHz, or 10 MHz




2 character x 20 character supertwist LCD

  • Time: UTC or local
  • Position: latitude, longitude, altitude
  • Receiver and clock status
  • 1 PPS (input) deviation
  • Event time
Status LEDs
  • Operate (green)
  • On Line (green)
  • Unlocked (red)
  • Fault (red)

In addition, when Option 10 (Clock Backup Battery) is ordered:

  • Battery Charge (green)
  • Battery in Use (green)
  • Battery Low (red)

Eight keys

  • Local time offset
  • Output code select: Local/UTC
  • Daylight Saving Time: On/Off/Automatic
  • Backlight control: On/Off/Automatic
  • Event input: Event/1 PPS, for each input A and B
  • Programmable Pulse setup
  • Antenna delay
  • Clock offset
  • Out-of-Lock time: 1 minutes to 99 minutes, Off, or Zero Delay
  • Auto-Survey: On/Off, Survey duration
  • Position Hold: On/Off, Position Auto/Manual
  • Option Configuration and Setup
  • Recorder output A/B
  • Frequency Reference: standard (internal) or external
  • Serial port: RS-232


Includes first serial port, second RS-232 port available (1088opt17A)


1200 baud to 19,200 baud; 7 or 8 data bits; 1 or 2 stop bits; even/odd/no parity

Broadcast modes
  • Standard ASCII (IRIG-J)
  • Extended ASCII
  • ASCII with Time Quality
  • ASCII with Time Quality and Year
  • Vorne large-display time
  • Status/Alarm
  • Event data

Male 9-pin D-sub (TXD, RXD)

Power Requirements



(IEC-320 Power Inlet) 85 Vac to 264 Vac, 47 Hz to 440 Hz, 20 VA maximum, 110 Vdc to 370 Vdc, 15 W maximum


(IEC-320 Power Inlet) IEC-320 with fuse and mating cordset. Specify option P01 - P10

Available cordset plug style and specifications are described in the Options and Accessories section




1 RU rack mount or tabletop, 260 mm deep FMS. Rack mounts included.
635 mm x 381 mm x 229 mm (25 in x 15 in x 9 in), shipping


2 kg (4.5 lbs), net
5.5 kg (12 lbs), shipping

  • 0.75 in pipe (1 in - 14 marine) thread
  • Cable Connection: F-type
  • Size: 80 mm hex (across flats) x 84 mm tall (3.2 in x 3.3 in), including connector
  • Weight: 170 g (6 oz)
Antenna Cable
  • RG-6 type
  • 15 m (50 ft) provided
  • Weight: 0.69 kg (1.52 lbs) per 15 m



Operating: 0 °C to + 50 °C (- 20 °C to + 70 °C typical)
Nonoperating: - 40 °C to + 75 °C



  • Radiated susceptibility: passes walkie-talkie test.
  • Conducted emissions: power supply complies with FCC 20780, Class A and VDE 0871/6.78 Class A.
  • Surge withstand capability (SWC), power inlet: designed to meet ANSI/IEEE C37.90-1 and IEC 801-4.

There are two internal option slots in the Model 1088B and options fit into two categories: those that require internal option slot space, and those that do not. Only one option may occupy the individual Option Slots. Available options are listed below and described in the Options and Accessories section.

1088opt04 1 Parallel BCD Output, 1 ms Resolution (1088B)
1088opt17 1 Parallel BCD with Second RS-232 Port
1088opt17A 1 Second RS-232 Port (1088B)
1088opt18 1 Self-Monitor, IRIG-B Distribution System and Redundant Control with Second RS-232 Port
1088opt19 1 Out-of-lock Relay 1 Form C SPDT [1088B]
1088opt20A 2 Four Configurable Fiber-Optic Outputs
1088opt23 2 COMTRADE Sample Rate Generator
1088opt27 1 8-Channel High Drive IRIG-B Output
1088opt28 2 Power System Time, Frequency, and Phase Monitor
1088opt29 1 Four Additional Outputs with Dry Contact and + 25/50 Vdc
1088opt34 1 Network Time Protocol (NTP) / Precision Time Protocol (PTP) Server
1088opt36 2 Four Configurable Outputs
1088opt01 LCD Backlight
1088opt07 85 Vac to 264 Vac RMS, 110 Vdc to 370 Vdc Terminal Power Strip (1088B)
1088opt08 10 Vdc to 60 Vdc Terminal Power Strip and Surge Withstand (1088B)
1088opt15A 110 Vdc to 170 Vdc Terminal Power Strip and Surge Withstand (1088B)
1088opt15B 110 Vdc to 300 Vdc Terminal Power Strip and Surge Withstand (1088B)

1 Uses Option Slot B
2 Uses Option Slot A

All Arbiter products are shipped with standard accessories as described on each product page. Additional accessories may also be ordered during the initial sale or afterward. Contact Arbiter technical support for additional information.

AS0028200 19 Inch Rack Mount Kit
AS0087800 Arbiter GPS Active Timing Antenna
CA0021315 1 15 m (50 ft) RG-6 Antenna Cable
P01 - P10 2 Country specific power cord with straight female end
PD0052600 Quick Setup Guide (1088)
AP0003400 3 BNC (Male) Breakout to 100 mm Wires
AP0007700 4 Modular DB-9 to RJ-11 Adapter, Preconfigured
AP0008900 3 BNC (Female) Breakout to 100 mm Wires
AP0013400 GPS Antenna Cable Splitter, F-Type, 950-2150 MHz, One Port Pass DC
AP0014900 BNC (Female) Breakout to Screw Terminal
AP0015000 BNC (Male) Breakout to Screw Terminal
AS0029900 Operation Manual (1088)
AS0033100 Rack Slide Kit
AS0044600 Antenna Mounting Kit
AS0044700 5 21 dB In-Line Pre-amplifier
AS0048900 Antenna Grounding Block Kit
AS0056600 24 Inch Rack Mount Kit
AS0067200 4 Programming Port Cable with adapter
AS0094500 GNSS Surge Protector
CA0019806 RS-232 Null Modem Cable, DB9F-DB9F, 2 m (6 ft) length
CA0021302 1 2 m (6 ft) RG-6 Antenna Cable
CA0021306 1 6 m (20 ft) RG-6 Antenna Cable
CA0021330 1 30 m (100 ft) RG-6 Antenna Cable
CA0021345 1 45 m (150 ft) RG-6 Antenna Cable
CA0021360 1 60 m (200 ft) RG-6 Antenna Cable
CA0021375 1 75 m (250 ft) RG-6 Antenna Cable
CA0022500 6 Option 28 System Frequency Reference Cable, 6 m (20 ft)
CA0023600 4 RJ-11 Cable Four-Pin Crossed, 2 m (7 ft)
CN0010550 7 50-Pin Parallel BCD Mating Connector
CN0027700 Type F, Male, RG-6 Antenna Cable Crimp-on Connector
CN0027800 Type F, Male, RG-11 Antenna Cable Crimp-on Connector
CN0031400 Type F, Male, RG-6 Plenum Rated Antenna Cable Crimp-on Connector
TF0006000 Type F, RG-11 Antenna Cable Crimp Tool
TF0006400 Type F, RG-6 Antenna Cable Crimp Tool
TF0013200 Antenna Cable Stripping Tool, RG-6
TF0013300 Antenna Cable Stripping Tool, RG-11
WC0004900 1 300 m (1000 ft) Roll RG-11 Cable
WC0005000 1 300 m (1000 ft) Roll RG-6 Cable
WC0005200 1 300 m (1000 ft) Roll RG-6 Plenum Rated Cable

1 Stocked length. Custom lengths available from 0.3 m (1 ft) to 300 m (1000 ft). Contact factory.
2 Only applies if Power Option 07 is ordered
3 Converts pair of wires to BNC.
4 Used with retired options: Option 32 or Option 33.
5 Used for cable lengths greater than: RG-6 75 m (250 ft) ; RG-11 120 m (400 ft)
6 Used with Option 28.
7 Used with Option 04.

Click to Download Latest Version of Software
Arbiter Time Service_01Jan2010_1500 PC Clock Synchronization Service for WIN NT/2000/XP/Vista/7. Not compatible with WIN 8.
Tera Term_01Jan2010_23 This is a very good HyperTerminal replacement. Able to capture data from Models 930A and 931A. Also able to program the GPS Satellite Controlled Clocks via serial commands.
TimeRC_3.0 NTP Server Test Utility. Screen Capture Utility.


Software Version and Related Information

Arbiter Time Service Tool (Arbiter Time Service)

PC Clock Synchronization Service for WIN NT/2000/XP/Vista/7. Not compatible with WIN 8. The Arbiter Time Service installs on Microsoft® Windows NT/2000/XP and runs as a service to keep the PC clock synchronized to an Arbiter GPS clock. The Arbiter Time Service connects with an RS-232 cable and interrogates the clock for the time signal

VersionRev LevelVersion Notes

Terminal Emulation Program (Tera Term)

Free software terminal emulator (communications program) for Microsoft Windows.

  • Tera Term (Pro) is a free software terminal emulator (communication program) for MS-Windows.
  • Supports VT100 emulation, telnet connection, serial port connection, etc.
  • Compatible with Windows 98, Windows NT, Windows 2000, Windows XP, Vista, Windows 7


Used as a test tool for NTP servers, synchronizes computer time over a network. Also used to save screen captures from the Model 930A, Model 931A, and Model 933A.

VersionRev LevelVersion Notes
Firmware Information (EPROM based firmware is not available for download)
1088B_Firmware_20Oct2016 Requires an EPROM update from Arbiter.
NTP/PTP Firmware_2.08_update-00.08 Downloadable. UNZIP, read instructions, and use the web/SSH interface to import apf file(s) into unit.
Power System Time, Frequency, and Phase Monitor Firmware_05Apr2012 Requires an EPROM update from Arbiter.


Firmware Version and Related Information

EPROM update (1088B_Firmware)

VersionRev LevelVersion Notes

Updates are not security related.

  1. Fix leap second operation to properly warn and implement the leap second.
  2. Fix external oscillator operation if used. Default operation is internal oscillator.
  3. Front panel SETUP menu of the B7 broadcast incorrectly included the Option 28 submenu. The Option 28 submenu should only be visible in the Option 28 main menu.
  4. Changed the IRIG-B Daylight Saving Time (DST) pending bit to change state at xx:59:01 (was starting at xx:59:00). Now it is consistent with Leap Second Pending bit operation.
  1. Baseline code alignment with other legacy clock models. Does not affect clock operation at the outputs (BZ734).
  1. DST stop error. Not exiting DST mode properly when "day of week" value matches the first day of the following month (BZ733). Example: DST will not properly stop if DST stop was set to Last Sunday of October and November 1 is also on a Sunday.
  2. Add Option 36 as a Slot B selection

Rerelease of 13Jun2013 firmware plagued by a compiler with the inane inability to determine what is an error.

Option 34 update:

  1. PTP enable/disable now shows on front panel display.
  2. Enabled leap second flags, leap second application time (seconds of year), and UTC-GPS seconds offset.
  3. Fixed formatting related to the version strings.

Option 28 update:

  1. Front panel configuration menu should skip to Auto Survey after Set Frequency not Option Setup (BZ717).

Option 34 and Option 35 updates:

  1. PTP enable/disable now shows on front panel display.
  2. Enabled leap second flags, leap second application time (seconds of year), and UTC-GPS seconds offset.
  3. Fixed formatting related to the version strings.

Option 28 update:

  1. Front panel configuration menu should skip to Auto Survey after Set Frequency not Option Setup (BZ717).
  1. Update the time quality functionality. Time quality no longer displays locked, maximum accuracy immediately after reacquiring satellites.
  2. Extended capability of existing version retrieval commands to show the Option 34/35 version information.
  1. The eight (8) channel Motorola VP receiver caused a clock reset at copyright screen (reference BZ 667).
  2. Option 28 did not fully configure using the front panel (reference BZ 668).
  1. Add Option 34/35 support.
  2. Add "IP" serial command to return Option 34/35 IP addresses.
  3. Add display of Option 34/35 MAC addresses
  4. Add bit to indicate if unit has ever been locked to GPS.
  5. Update NTP status screens.
  6. Fix IP command buffer and non-response issue.
  7. Fix IP address display to use periods (.) instead of colons (:).
  1. Update RD serial command output to be consistent with 1092/3 (Reference BZ489).
  2. Fix Option 28 XI serial command configuration command (Reference BZ490).
  3. Leap second pending always 0 for Motorola 8-chan receiver (Reference BZ632).
  4. NMEA GLL serial broadcast made uniform (Reference BZ633).
  5. Fix IR serial command intermittent system lock (Reference BZ644).
  6. Fix Event/Deviation screen pause (Reference BZ645).
  1. Removed RS-232 setup options for Option 19. The 1088B Option 19 is the out-of-lock relay and has no RS-232 functions. (BZ 613)

Downloadable Firmware (NTP/PTP Firmware)

The zip file contains all files and PDF instructions necessary to update the Network Time Protocol (NTP) / Precision Time Protocol (PTP) firmware. Reminder: Unzip the downloaded file to access the PDF instructions and individual update files.

VersionRev LevelVersion Notes

Updates are not security related.

1. Updates sys_monitor-01.05. The new sys_monitor corrects a bug in the frequency tuning algorithm that results in high system time offsets on some units. Whether or not a system is susceptible to this bug depends on the initial frequency of the on-board oscillator prior to tuning. It is likely that a system showing low offset now will continue to work. However, to be safe, the update is recommended.

Support  > Version
Core: 2.4
Auth01: 2.2
TPS UI Content: 2.2
Startup App: 1.3
System Monitor: 1.5
CLOI: 1.10

Reminder: Unzip the downloaded file to access the PDF instructions and individual apf update files.



  1. Update NTP to latest release (4.2.8p8) to protect against a known vulnerability.
  2. Modified the NTP server configuration to allow correct responses to queries at a rate higher than once every 4 seconds.
  3. Fixed a bug that prevents the proper network filter configuration for vlan interfaces resulting in vlans not functioning.
  4. Fixed a bug preventing getting the OS version from the serial port
  5. Improved robustness of the update process.

EPROM Update (Power System Time, Frequency, and Phase Monitor Firmware)

VersionRev LevelVersion Notes
  1. The frequency was unstable off nominal frequency with an error proportional to frequency deviation. Fixed a conversion factor in the calculation. (BZ 692)
  1. Improved compatibility during transfer of correction values to option 28.

Establishing Traceability of Synchrophasors at the National Laboratory Level
Download cris2004_Establish_credibility_syncrophasor_measurements.pdf (68 kB) »

GPS Substation Clock Requirements
Download gps_substation_clock_requirements.pdf (25 kB) »

IRIG-B Time Code Accuracy, IED and System Design Issues
Download irig_accuracy_and_connection_requirements.pdf (31 kB) »

NERC PRC-08 Compliance Statement
Download pd0042900a_NERC_PRC-018_compliance_statement.pdf (75 kB) »

Time in the Power Industry: How and Why We Use It
Download TimeInThePowerIndustry.pdf (407 kB) »

Why GPS Clocks Are Not Free
Download why_gps_clocks_arent_free.pdf (12 kB) »

App Note 101: Distributing Timing Signals in a High-EMI Environment
Download application_note_101.pdf (90 kB) »

App Note 102: Synchronizing End-to End Relay Testing with Model 1088B
Download application_note_102.pdf (18 kB) »

App Note 103: Large Format Displays with Arbiter products
Download application_note_103.pdf (16 kB) »

COMTRADE Sample Rate Generator
Download ds_comt.pdf (27 kB) »

Continual Self Calibration with Power System Time, Frequency and Phase Monitor Option 28
Download power_system_time_freq_phase_monitor_continually_cal.pdf (12 kB) »

GPS Antenna Mounting Bracket
Download antenna_mnt_bracket_brief.pdf (462 kB) »

GPS Antenna Mounting Bracket Instructions
Download pd0024700_gps_antenna_mounting_bracket.pdf (580 kB) »

GNSS Antenna Preamplifier Installation Instructions
Download pd0025300_gnss_antenna_preamplifier.pdf (3 MB) »

IRIG Standard 200-16
Download irig-b_200-16.pdf (857 kB) »

IRIG-B Specifications
Download irig_b_spec_brief.pdf (488 kB) »

Internal Network Time Protocol (NTP) Server -DISCONTINUED-
Download ntp.pdf (22 kB) »

Internal Network Time Protocol (NTP) Server Español -DISCONTINUED-
Download ntp_option32_espanol.pdf (129 kB) »

Option 32: Internal NTP Server Setup and Operation Guidelines -DISCONTINUED-
Download ntp_option32_english.pdf (279 kB) »

Option 33: Dual Internal NTP Server Setup and Operation Guidelines -DISCONTINUED-
Download ntp_option33_english.pdf (301 kB) »

Option 34: Network Time Protocol (NTP)/Precision Time Protocol (PTP) Server Data Sheet
Download Option34_NTP_PTP.pdf (22 kB) »

Power System Time, Frequency and Phase Monitor
Download power_system_time_freq_phase_monitor.pdf (152 kB) »

Self-Monitor, IRIG-B Distribution System and Second RS-232
Download self_monitor_irigb_distribution_system.pdf (20 kB) »

Windows® Time Service Configuration
Download w32time.pdf (14 kB) »

Arbiter Time Service Installation Instructions
Download pd0041300_ArbiterTimeServiceInstall.pdf (382 kB) »

Chassis Dimensions
Download chassis.pdf (27 kB) »

Clock Option Selection Guide
Download clock_option_selection_guide.pdf (22 kB) »

Clock Selection Guide
Download clock_selection_guide.pdf (22 kB) »

Model 1088B Option List Español
Download 1088_optionlist_espanol.pdf (1 MB) »

Timing Products Options and Accessories
Download timing_and_frequency_options.pdf (36 kB) »

Model 1088A/B Firmware Upgrade Instructions
Download 1088_DST_ROM_instructions.pdf (309 kB) »

Option 28 Firmware Upgrade Instructions
Download Option28_DST_ROM_instructions.pdf (154 B) »

GPS Surge Protector Installation Instructions
Download pd0045800_surge_protector_installation_instructions.pdf (80 kB) »

Timing Signals, IRIG-B and Pulses
Download pd0043200_timing_signals_overview.pdf (197 kB) »

Catalogo de Productos de Sincronizacion y Frecuencia
Download catalogo_de_productos_de_sincronizacion_y_frecuencia.pdf (216 kB) »

Press Release: Leap Second Anomaly December 2016
Download PD0054900_LeapSecondPressRelease.pdf (70 kB) »

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