The CNS Clock

The CNS Clock is a GPS clock with high accuracy one-pulse-per-second outputs and software that manages the clock and keeps your computer's time synchronized to GPS.

The CNS Clock is available in a rack mount version that allows up to three clocks per 3.5 inch panel.

CNS Clock Features:

Two external low impedance, fast rise time 1PPS signals for "laboratory" applications.

Two external RS232 level 1PPS signals for computer applications.

A high efficiency switching power supply that operates from any 9-30 volt DC source.

Optional IRIG-B time code interface.

Optional Paging Sequencer Module for synchronizing paging base stations with overlapping coverage.

Optional Serial Protocol Module custom applications using the serial port such as the Genysis module for the railroad industry. Contact CNS Systems for information on custom configurations.

Battery Backup so the GPS receiver can wake up "smart."

Provides 5 volt dc power for an amplified GPS antenna. Other voltages optional.

Tac32 software with a wide range of timing features as well as self-survey, logging, 1PPS steering, and PC clock synchronization.

Optional Tac32Plus software for advanced applications.

EMI certified to FCC Part 15, Subpart B and CISPR 22:1994 (both radiated and conducted emissions).

Accuracy: In position hold mode, <20 nsec 1-sigma with SA off.

Hardware:

The core of the CNS Clock is a GPS receiver module. The standard version of the CNS Clock features the best available GPS receiver, the Motorola M12+ Timing module.

Each of the external 1 PPS output signals are independently buffered to improve their drive capabilities and to prevent damage to the GPS receiver module. The buffers will drive +3 volts into a 50 ohm termination with a rise time of <10 nsec. The normal logic polarity is positive going at the epoch time, but this can be inverted if desired.

An RS232 driver provides 1 PPS time synchronization to an attached computer. The 1 PPS signal is normally connected to the computer's DCD input but connection to CTS or DSR is supported.

The RS232 I/O ports are buffered and isolated from the GPS receiver module.

Two RS232 ports are provided, a primary and a secondary. This allows, for example, control and monitoring using Tac32 software on one port while the other port is used fo a second computer, running NTP software.

External Interfaces:

Two RS-232 1 Ports.
TNC Female Antenna Connector.
Two BNC Female buffered 1 pulse-per-second (1PPS) outputs.
Power connector, 2.1x5.5 mm coaxial, 9-30 volts @ 250ma (nominal).
Fuse: 1/5 amp, 250 volt, fast acting, 5x20 mm.
Optional IRIG-B Interface.
Optional Paging Sequencer Module interface (PTT or Busy logic).

Y2000 and Week Rollover Compliance

Options:

IRIG-B Module: The IRIG-B Module provides an industry standard IRIG-B modulated time code signal on a rear panel BNC connector. The signal is buffered so that it can drive long lengths of 50 ohm coaxial cable (RG-58 or equivalent). The module can also be set by an internal jumper to provide a non-modulated IRIG-B signal for short length interconnects.

IRIG-B time code signals are available in any of the three IRIG-B modulation schemes as defined in IRIG STANDARD 200-98, May 1998. These are the Amplitude Modulated Carrier (standard), Pulse Width Code, and the Manchester modulated waveforms. This includes modes B000, B003, B120, B123, B220, and B223 (CF bits set to zero unless otherwise specified). The selection is by internal jumper. Custom applications using the control function (CF) bits are possible. Contact CNS Systems for information.

Paging Sequencer Module: The Paging Sequencer Module is designed to control the Active/Busy states of a paging transmitter station as a specific portion of each minute to allow spectrum sharing with adjacent paging systems that have overlapping coverage areas.

The interface is designed to connect directly to a variety of pager terminals by using the terminal's "Busy" line. The Zetron 2200 "Busy" interface is on the Station Card. The Kantronics Model 2000 is supported by connecting the interface to the External Carrier Detect line. On the Motorola Unipage M15 Paging Terminal connect to "Busy Channel Control" and "Ground" (pins 45 and 50) on the standard 25-pair punch block. The GlenAyre terminal is also supported. The interface is an opto-isolated solid state switch that operates much like a relay. When closed, the circuit must not draw more than 40ma. When open, the terminal voltage must not exceed 30 volts. The connector on the rear panel of the CNS Clock is an isolated BNC with the emitter of U3 connected to the outer shell and the collector connected to the center pin. This way there can be no ground loops between the paging system and the CNS Clock.

Click here to get the Paging Sequencer Module Brochure in Adobe PDF format (requires Acrobat Reader V8.0 or newer).

Tac32 Software displays the current UTC or local time in BIG DIGITS. It also includes date, day-of-week, day-of-year, Local and Greenwich Mean Sidereal times, Julian Date, Modified Julian Date, and current GPS week.

Other features include data logging in various formats; audible time ticks; automatically sets the PC's internal clock; corrects for time delays in antenna and measurement cables; satellite display with bar graph "S-meter"; self-survey; timing, position and DGPS operating modes (for VP receivers only); configuration selections are saved and restored.

Tac32 runs on Windows 95, 98, ME and NT4/2000/XP. Recommended minimum configuration is Pentium 200 with 128 Mb RAM.

Tac32Plus Software has all the features of Tac32 plus it adds advanced capabilities that support professional applications:

Time Interval Counter (TIC) module.
Remote control of logging functions via TCP/IP.
Built-in SNTP time server.
Ability to run as a service under Windows NT/2000/XP.
Can run multiple instances of Tac32Plus with separate registry trees and serialization files.

Tac32Multi Software has all the features of Tac32Plus plus

Can simultaneously manage up to eight Time Interval Counters.

Accessories

SMA-35 Antenna: The SMA-35 is a high performance GPS patch antenna combing a state-of-the-art low noise amplifier with a low profile, compact, fully waterproof enclosure. When connected to a GPS receiver with 3-5 VDC antenna power, the SMA-35 provides excellent signal amplification in addition to out-of-band filtering & rejection. A 25 dB active patch, the SMA-35 antenna operates from 3 to 5 VDC at just 12 mA supplied by the CNS Clock. The SMA-35 features a 5 meter 1/8 inch diameter RG-174 coaxial cable with BNC connector (a BNCTNC adaptor is needed for use with the CNS Clock). The antenna design reflects a high standard for performance when operating in foliage/urban canyon environments and in the presence of electromagnetic interference.


VIC-100 Timing Antenna: A high performance active antenna with vertical cable feed. Designed for easy installation. Click on the picture of the antenna at the right to access the product brochure in Adobe Acrobat format (requires Acrobat Reader V6.0 or newer). General Specifications: Operating Frequency: 1575.42± 1.023 MHz (typical) Gain: 30 dB (min), N.F. 2.2 dB (max), Filtering: -60 dB (typ) @ 1575.4 ± 50MHz Polarization: Right hand circular, Output: VSWR 1.5 (typ) 2.5(max). Power supply: 5 ± 0.5 VDC, Current: 20 mA (typ), 27 mA (max ).		Available with TNC, N and N+Mount
VIC100TNC VIC100NMNT VIC100N		VIC-100 with TNC
Coaxial Cable: For lengths up to 150 feet, LMR-240 cable from Times Wire is a very good choice. This cable is about the size and flexibility of CATV cable but is 50 ohms impedance and has loss characteristics similar to RG-213 while being half the diameter of RG213. Specifications: Loss at GPS frequency is approximately 9db/100 feet. Has .059" center conductor with micro-cell foam dielectric & type IIIA non-contaminating jacket. Nominal impedance 50 Ohms, velocity of propagation 82%; outer diameter .240"; 100% Al mylar & 95% tinned Cu braid. Preassembled cables with TNC connectors and weatherproof heatshrink tubing are available in standard lengths of 50, 75, 100 and 150 feet. Custom cables of any type coax, in any length and with any connectors are available. These can usually be shipped within 5 business days. Call or e-mail for quotes.