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- <TITLE>Spectracom 8170 and Netclock/2 WWVB Receivers
-</TITLE>
-</HEAD>
-<BODY>
-
-<H3>
-Spectracom 8170 and Netclock/2 WWVB Receivers</H3>
-
-<HR>
-<H4>
-Synopsis</H4>
+<HTML><HEAD><TITLE>
+Spectracom 8170 and Netclock/2 WWVB Receivers
+</TITLE></HEAD><BODY><H3>
+Spectracom 8170 and Netclock/2 WWVB Receivers
+</H3><HR>
+
+<H4>Synopsis</H4>
+
Address: 127.127.4.<I>u</I>
<BR>Reference ID: <TT>WWVB</TT>
<BR>Driver ID: <TT>WWVB_SPEC</TT>
-<BR>Serial Port: <TT>/dev/wwvb<I>u</I></TT>; 9600 baud, 8-bits, no parity
+<BR>Serial Port: <TT>/dev/wwvb<I>u</I></TT>; 9600 baud, 8-bits, no
+parity
<BR>Features: <TT>tty_clk</TT>
-<H4>
-Description</H4>
-This driver supports the Spectracom Model 8170 and Netclock/2 WWVB Synchronized
-Clock. This clock has proven a reliable source of time, except in some
-cases of high ambient conductive RF interference. The claimed accuracy
-of the clock is 100 usec relative to the broadcast signal; however, in
-most cases the actual accuracy is limited by the precision of the timecode
-and the latencies of the serial interface and operating system.
-
-<P>The DIPswitches on this clock should be set to 24-hour display, AUTO
-DST off, data format 0 or 2 (see below) and baud rate 9600. If this clock
-is to used as the source for the IRIG Audio Decoder (refclock_irig.c in
-this distribution), set the DIPswitches for AM IRIG output and IRIG format
-1 (IRIG B with signature control).
+
+<H4>Description</H4>
+
+This driver supports all known Spectracom radio and satellite clocks,
+including the Model 8170 and Netclock/2 WWVB Synchronized Clocks and the
+Netclock/GPS GPS Master Clock. The claimed accuracy of the WWVB clocks
+is 100 usec relative to the broadcast signal. These clocks have proven a
+reliable source of time, except in some parts of the country with high
+levels of conducted RF interference. WIth the GPS clock the claimed
+accuracy is 130 ns. However, in most cases the actual accuracy is
+limited by the precision of the timecode and the latencies of the serial
+interface and operating system.
+
+<P>The DIPswitches on these clocks should be set to 24-hour display,
+AUTO DST off, data format 0 or 2 (see below) and baud rate 9600. If this
+clock is used as the source for the IRIG Audio Decoder
+(<tt>refclock_irig.c</tt> in this distribution), set the DIPswitches for
+AM IRIG output and IRIG format 1 (IRIG B with signature control).
<P>There are two timecode formats used by these clocks. Format 0, which
-is available with both the Netclock/2 and 8170, and format 2, which is
-available only with the Netclock/2 and specially modified 8170.
+is available with all clocks, and format 2, which is available with all
+clocks except the original (unmodified) Model 8170.
<P>Format 0 (22 ASCII printing characters):
-<PRE><cr><lf>i ddd hh:mm:ss TZ=zz<cr><lf>
+<br><cr><lf>i ddd hh:mm:ss TZ=zz<cr><lf>
-on-time = first <cr>
-i = synchronization flag (' ' = in synch, '?' = out synch)
-hh:mm:ss = hours, minutes, seconds</PRE>
-The alarm condition is indicated by other than ' ' at <TT>i</TT>, which
-occurs during initial synchronization and when received signal is lost
-for about ten hours.
+<p>on-time = first <cr>
+<br>i = synchronization flag (' ' = in synch, '?' = out synch)
+<br>hh:mm:ss = hours, minutes, seconds</PRE>
+
+<p>The alarm condition is indicated by other than ' ' at <TT>i</TT>,
+which occurs during initial synchronization and when received signal is
+lost for about ten hours.
<P>Format 2 (24 ASCII printing characters):
-<PRE><cr><lf>iqyy ddd hh:mm:ss.fff ld
-
-on-time = <cr>
-i = synchronization flag (' ' = in synch, '?' = out synch)
-q = quality indicator (' ' = locked, 'A'...'D' = unlocked)
-yy = year (as broadcast)
-ddd = day of year
-hh:mm:ss.fff = hours, minutes, seconds, milliseconds</PRE>
-The alarm condition is indicated by other than ' ' at <TT>i</TT>, which
-occurs during initial synchronization and when received signal is lost
-for about ten hours. The unlock condition is indicated by other than '
-' at <TT>q</TT>.
+<br>lt;cr>lf>iqyy ddd hh:mm:ss.fff ld
+
+<p>on-time = <cr>
+<br>i = synchronization flag (' ' = in synch, '?' = out synch)
+<br>q = quality indicator (' ' = locked, 'A'...'D' = unlocked)
+<br>yy = year (as broadcast)
+<br>ddd = day of year
+<br>hh:mm:ss.fff = hours, minutes, seconds, milliseconds</PRE>
+
+<p>The alarm condition is indicated by other than ' ' at <TT>i</TT>,
+which occurs during initial synchronization and when received signal is
+lost for about ten hours. The unlock condition is indicated by other
+than ' ' at <TT>q</TT>.
<P>The <TT>q</TT> is normally ' ' when the time error is less than 1 ms
-and a character in the set <TT>A...D</TT> when the time error is less than
-10, 100, 500 and greater than 500 ms respectively. The <TT>l</TT> is normally
-' ', but is set to <TT>L</TT> early in the month of an upcoming UTC leap
-second and reset to ' ' on the first day of the following month. The <TT>d</TT>
-is set to <TT>S</TT> for standard time <TT>S</TT>, <TT>I</TT> on the day
-preceding a switch to daylight time, <TT>D</TT> for daylight time and <TT>O</TT>
-on the day preceding a switch to standard time. The start bit of the first
-<cr> is synchronized to the indicated time as returned.
-
-<P>This driver does not need to be told which format is in use - it figures
-out which one from the length of the message. A three-stage median filter
-is used to reduce jitter and provide a dispersion measure. The driver makes
-no attempt to correct for the intrinsic jitter of the radio itself, which
-is a known problem with the older radios.
-<H4>
-Monitor Data</H4>
+and a character in the set <TT>A...D</TT> when the time error is less
+than 10, 100, 500 and greater than 500 ms respectively. The <TT>l</TT>
+is normally ' ', but is set to <TT>L</TT> early in the month of an
+upcoming UTC leap second and reset to ' ' on the first day of the
+following month. The <TT>d</TT> is set to <TT>S</TT> for standard time
+<TT>S</TT>, <TT>I</TT> on the day preceding a switch to daylight time,
+<TT>D</TT> for daylight time and <TT>O</TT> on the day preceding a
+switch to standard time. The start bit of the first
+<cr> is synchronized to the indicated time as returned.
+
+<P>This driver does not need to be told which format is in use - it
+figures out which one from the length of the message. A three-stage
+median filter is used to reduce jitter and provide a dispersion measure.
+The driver makes no attempt to correct for the intrinsic jitter of the
+radio itself, which is a known problem with the older radios.
+
+<H4>Monitor Data</H4>
+
The driver writes each timecode as received to the <TT>clockstats</TT>
file. When enabled by the <TT>flag4</TT> fudge flag, a table of quality
data maintained internally by the Netclock/2 is retrieved and written to
-the <TT>clockstats</TT> file when the first timecode message of a new day
-is received.
-<H4>
-Fudge Factors</H4>
+the <TT>clockstats</TT> file when the first timecode message of a new
+dayis received.
+
+<H4>Fudge Factors</H4>
<DL>
-<DT>
-<TT>time1 <I>time</I></TT></DT>
-<DD>
-Specifies the time offset calibration factor, in seconds and fraction,
+<DT><TT>time1 <I>time</I></TT></DT>
+<DD>Specifies the time offset calibration factor, in seconds and
+fraction,
with default 0.0.</DD>
-<DT>
-<TT>time2 <I>time</I></TT></DT>
-
-<DD>
-Not used by this driver.</DD>
-
-<DT>
-<TT>stratum <I>number</I></TT></DT>
-
-<DD>
-Specifies the driver stratum, in decimal from 0 to 15, with default 0.</DD>
-
-<DT>
-<TT>refid <I>string</I></TT></DT>
+<DT><TT>time2 <I>time</I></TT></DT>
+<DD>Not used by this driver.</DD>
-<DD>
-Specifies the driver reference identifier, an ASCII string from one to
-four characters, with default <TT>WWVB</TT>.</DD>
+<DT><TT>stratum <I>number</I></TT></DT>
+<DD>Specifies the driver stratum, in decimal from 0 to 15, with default
+0.</DD>
-<DT>
-<TT>flag1 0 | 1</TT></DT>
+<DT><TT>refid <I>string</I></TT></DT>
+<DD>Specifies the driver reference identifier, an ASCII string from one
+to four characters, with default <TT>WWVB</TT>.</DD>
-<DD>
-Not used by this driver.</DD>
+<DT><TT>flag1 0 | 1</TT></DT>
+<DD>Not used by this driver.</DD>
-<DT>
-<TT>flag2 0 | 1</TT></DT>
+<DT><TT>flag2 0 | 1</TT></DT>
+<DD>Not used by this driver.</DD>
-<DD>
-Not used by this driver.</DD>
+<DT><TT>flag3 0 | 1</TT></DT>
+<DD>Not used by this driver.</DD>
-<DT>
-<TT>flag3 0 | 1</TT></DT>
+<DT><TT>flag4 0 | 1</TT></DT>
+<DD>Enable verbose <TT>clockstats</TT> recording if set.</DD>
-<DD>
-Not used by this driver.</DD>
-
-<DT>
-<TT>flag4 0 | 1</TT></DT>
-
-<DD>
-Enable verbose <TT>clockstats</TT> recording if set.</DD>
</DL>
-Additional Information
-<P><A HREF="refclock.htm">Reference Clock Drivers</A>
-<HR>
-<ADDRESS>
-David L. Mills (mills@udel.edu)</ADDRESS>
+Additional Information
-</BODY>
-</HTML>
+<P><A HREF="refclock.htm">Reference Clock Drivers</A>
+<HR><ADDRESS>David L. Mills (mills@udel.edu)</ADDRESS></BODY></HTML>
projects / thirdparty / ntp.git / commitdiff
