Meinberg WVB600USB User manual
MANUAL
WVB600USB
USB PC CLOCK
29th July 2011
Meinberg Radio Clocks GmbH & Co. KG
Page 0
Table of Contents
1 General information about WWVB 1
1.1 CodeFormat.............................................. 1
2 Overview: WVB600USB 2
2.1 Installation............................................... 2
2.1.1 PowerSupply ......................................... 2
2.1.2 General information about position of antenna . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1.3 StatusLEDs.......................................... 3
3 Technical Specifications WVB600USB 4
4 Content of the USB stick 5
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Date: 29th July 2011 WVB600USB
Page 1
1 General information about WWVB
NIST radio station WWVB is located near Fort Collins, Colorado, on the same site as station WWV. The WWVB
broadcast is used by millions of people throughout North America to synchronize consumer electronic timing prod-
ucts such as wall clocks, clock radios, and wristwatches. In addition, WWVB is used for high level applications
including network time synchronization and frequency calibration. The WWVB transmission is maintained by the
National Institute of Standards and Technology (NIST).
WWVB continuously broadcasts a time and frequency signal at 60 kHz. The carrier frequency provides a stable
frequency reference traceable to the national standard. There are no voice announcements on the station, but
a time code is synchronized with the 60 kHz carrier and broadcast continuously at the rate of 1 bit per second
using pulse width modulation. The carrier power level is modulated to encode the time data. The carrier power
is reduced by 17 dB at the start of each second, so that the leading edge of every negative going pulse is on
time. Full power is restored 0.2 s later for a binary #0#, 0.5 s later for a binary #1#, or 0.8 s later to convey
a position marker. The binary coded decimal (BCD) format is used, which combines binary digits to represent
decimal numbers. The time code contains the year, day of year, hour, minute, second, and ags that indicate
the status of Daylight Savings Time, leap year, and leap seconds. WWVB identifes itself by advancing its carrier
phase 45 degrees at 10 minutes after the hour and returning to normal phase at 15 minutes after the hour. If you
plot WWVB phase, this results in a phase step of approximately 2.08 microseconds.
1.1 Code Format
WVB600USB Date: 29th July 2011
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Page 2 2 Overview: WVB600USB
2 Overview: WVB600USB
The radio remote clock WVB600USB has been designed for communication via the USB interface. The required
power is provided via the USB cable as well, so there is no need for any external power supply.
The WWVB signal received by the internal antenna is passed to the on-board LF receiver where it is demodulated
by a synchronous detector with automatic gain control. The demodulated time marks from the receiver circuit are
ltered and decoded by the microprocessor. If no errors are detected in the current time message an additional
plausibility check against the previous time message is performed. If that plausibility check passes, too, the real
time clock on the board is adjusted corresponding to the decoded time and date.
The WVB600USB module provides two integrated LEDs, which show the demodulated time marks (MOD LED)
and the state of synchronisation (FR LED). The scope of supply includes an USB cable with 3 mtrs. of length to
connect the WVB600USB directly to a PC's USB port.
Also included is the driver software for Windows 2000/XP/VISTA/WIN 7
R
operating systems that is used
to set the system time of the computer and shows the important status information of the WVB600USB.
Driver software for other operating systems can be found on the Meinberg homepage for download:
http://www.meinberg.de/english/sw/index.htm
2.1 Installation
WWVB Antenna
Free Run
Modulation USB
2.1.1 Power Supply
The WVB600USB is powered via the PC's USB port. After connecting the USB port the radio clock is ready to
operate. For proper operation it is essential to pay attention to the following points.
2.1.2 General information about position of antenna
The antenna of WWVB-receivers includes a ferrite rod which must be aligned to the transmitter. For best recep-
tion the longitudinal side of the antenna must point to the transmitter, which is lacated in Fort Collins, Colorado.
The antenna should be installed with a distance of at least 30cm to all metal objects because they would detune
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Date: 29th July 2011 WVB600USB
2.1 Installation Page 3
the antenna resonance. A distance of several meters to computer monitors must be kept. If they are running in
a high screen resolution mode, their line frequency is close to the carrier frequency of the WWVB transmitter,
which would cause a worse or no reception.
2.1.3 Status LEDs
The two LEDs Mod and FR reect the state of synchronisation of the decoded time marks of the WVB600USB.
If the antenna is installed properly and the signal from WWVB can be received without strong distortions, the
green LED labeled Mod starts blinking exactly once per second, corresponding to the time marks from WWVB.
If this LED ashes intermediately, there is some electrical noise around which prevents the microprocessor from
decoding the time message. In this case, a better location for the antenna must be found. After start-up, the
red LED labeled FR (free running) indicates that the clock is running on XTAL and has not synchronized with
WWVB yet. Due to the plausibility checks, it can take up to three minutes after power-up until the clock is
synchronized and this LED is turned o. The state of this LED only changes when a new minute begins. Without
or with a disturbed RF signal the clock runs on XTAL with an accuracy of 10-6 (after 24 hours of synchronous
operation).
WVB600USB Date: 29th July 2011
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Page 4 3 Technical Specications WVB600USB
3 Technical Specifications WVB600USB
RECEIVER: narrowband straight receiver with automatic gain control
bandwidth: approx. 40Hz
reception via internal or external ferrite antenna
MODULATION: demodulated time marks indicated by LED
TIMECODE
CHECK: Multiple software check of the incoming timecode
Parity and consistency check over a period of two minutes
FREE RUNNING: Without RF signal the clock runs on XTAL with an
accuracy of 1*10E-6 (after 24h of synchronous operation)
Disturbed reception indicated by LED
BATTERY
BACKUP: In case of supply voltage failure the on-board RTC keeps the time
based on XTAL for more than 140 hours (buer capacitor)
RELIABILITY OF
OPERATION: Microprocessor supervisory circuit provides watchdog timer,
power supply monitoring and backup-battery switchover
INTERFACE: USB 2.0 (Universal Serial Bus)
TIME ZONE: UTC/BST (standard)
CONNECTORS: USB connector type B
SMB antenna connector (male)
POWER SUPPLY: 5V, via USB interface of the PC
current consuption: approx. 90 mA
HOUSING: plastic housing, IP30 protected
73mm x 117mm x 24mm (width x depth x height)
AMBIENT
TEMPERATURE: 0 ... 50
◦
C
HUMIDITY: max. 85 %
CE Label
This device conforms to the directive 2004/108/EC
on the approximation of the laws of the Member
States of the European Community relating to
electromagnetic compatibility.
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Date: 29th July 2011 WVB600USB
Page 5
4 Content of the USB stick
The included USB stick contains a driver program that keeps the computers system time synchronous to the
received time. If the delivered stick doesn't include a driver program for the operating system used, it can be
downloaded from:
http://www.meinberg.de/german/sw/
On the USB stick there is a le called "readme.txt", which helps installing the driver correctly.
WVB600USB Date: 29th July 2011
5
Konformitätserklärung
Declaration of Conformity
Hersteller Meinberg Funkuhren GmbH & Co. KG
Manufacturer Lange Wand 9
D-31812 Bad Pyrmont
erklärt in alleiniger Verantwortung, daß das Produkt
declares under its sole responsibility, that the product
Produktbezeichnung WWVB Funkuhr
Product Name
Modell / Typ WVB600USB
Model Designation
auf das sich diese Erklärung bezieht, mit den folgenden Normen übereinstimmt
to which this declaration relates is in conformity with the following standards
EN55022:2008-05, Class B Grenzwerte und Meßverfahren für Funkstörungen von
informationstechnischen Einrichtungen
Limits and methods of measurement of radio interference characteristics of
information technology equipment
EN55024:2003-10 Grenzwerte und Meßverfahren für Störfestigkeit von
informationstechnischen Einrichtungen
Limits and methods of measurement of Immunity characteristics of
information technology equipment
gemäß den Richtlinien 2004/108/EG (Elektromagnetische Verträglichkeit), 2006/95/EG (Nieder-
spannungsrichtlinie) und 93/68/EWG (CE Kennzeichnung) sowie deren Ergänzungen.
following the provisions of the directives 2004/108/EC (electromagnetic compatibility), 2006/95/EC (low voltage directive) and
93/68/EEC (CE marking) and its amendments.
Bad Pyrmont, den 28.07.2011
