-Spectracom 8170 and Netclock/2 WWVB Receivers -

From 52f0477edd81105d995864898a64a601b67d66d8 Mon Sep 17 00:00:00 2001 From: roberto Date: Tue, 20 Jul 2004 15:19:51 +0000 Subject: Merge conflicts. Lots of added files, some removed and quite a large number of renames :( --- contrib/ntp/html/driver4.htm | 126 ------------------------------------------- 1 file changed, 126 deletions(-) delete mode 100644 contrib/ntp/html/driver4.htm (limited to 'contrib/ntp/html/driver4.htm') diff --git a/contrib/ntp/html/driver4.htm b/contrib/ntp/html/driver4.htm deleted file mode 100644 index 4f3abd7..0000000 --- a/contrib/ntp/html/driver4.htm +++ /dev/null @@ -1,126 +0,0 @@ - -Spectracom 8170 and Netclock/2 WWVB Receivers -

-Spectracom 8170 and Netclock/2 WWVB Receivers -

- -

Synopsis

- -Address: 127.127.4.u -
Reference ID: WWVB -
Driver ID: WWVB_SPEC -
Serial Port: /dev/wwvbu; 9600 baud, 8-bits, no -parity -
Features: tty_clk - -

Description

- -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. - -

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 -(refclock_irig.c in this distribution), set the DIPswitches for -AM IRIG output and IRIG format 1 (IRIG B with signature control). - -

There are two timecode formats used by these clocks. Format 0, which -is available with all clocks, and format 2, which is available with all -clocks except the original (unmodified) Model 8170. - -

Format 0 (22 ASCII printing characters): -
<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 - -

The alarm condition is indicated by other than ' ' at i, -which occurs during initial synchronization and when received signal is -lost for about ten hours. - -

Format 2 (24 ASCII printing characters): -
lt;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 - -

The alarm condition is indicated by other than ' ' at i, -which occurs during initial synchronization and when received signal is -lost for about ten hours. The unlock condition is indicated by other -than ' ' at q. - -

The q is normally ' ' when the time error is less than 1 ms -and a character in the set A...D when the time error is less -than 10, 100, 500 and greater than 500 ms respectively. The l -is normally ' ', but is set to L early in the month of an -upcoming UTC leap second and reset to ' ' on the first day of the -following month. The d is set to S for standard time -S, I on the day preceding a switch to daylight time, -D for daylight time and O on the day preceding a -switch to standard time. The start bit of the first -<cr> is synchronized to the indicated time as returned. - -

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. - -

Monitor Data

- -The driver writes each timecode as received to the clockstats -file. When enabled by the flag4 fudge flag, a table of quality -data maintained internally by the Netclock/2 is retrieved and written to -the clockstats file when the first timecode message of a new -dayis received. - -

Fudge Factors

- -

time1 time: Specifies the time offset calibration factor, in seconds and -fraction, -with default 0.0.
time2 time: Not used by this driver.
stratum number: Specifies the driver stratum, in decimal from 0 to 15, with default -0.
refid string: Specifies the driver reference identifier, an ASCII string from one -to four characters, with default WWVB.
flag1 0 | 1: Not used by this driver.
flag2 0 | 1: Not used by this driver.
flag3 0 | 1: Not used by this driver.
flag4 0 | 1: Enable verbose clockstats recording if set.

- -Additional Information - -

Reference Clock Drivers -

David L. Mills (mills@udel.edu)

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