Time Code generator
On another list to which I subscribe, the question was asked about the
suitability of recording WWV 2.5mhz audio as one track when recording
off the air signals of interest as a time reference.
The person who asked the question didn't really state his intentions but
they seem very similar to my immediate needs. That is, simply a time
reference - that is "the time", the start of the minute, and periodic
references (i.e. seconds) between the announcements.
It seems that recording the audio of something like WWV or CHU is ideal.
However, another approach would be recording a more proper time code
signal as you might have available from a "precision clock". Of course,
a decoder would also be required.
A quick Google search turned up lots of leads which I have yet to sort
through. In the interim I thought I would pose the question to the
learned members of this group for their suggestions. Keep in mind KISS
and that a very high degree of accuracy is not required.
Is there an opensource/freeware PC app that will generate an appropriate
time code signal that can be recorded on one track of an audio recorder
(either PC based i.e. Audacity or standalone) that will also decode via
soundcard or other input?
Cheers, Graham ve3gtc
Hello The Net:
Another possible application is for a pocket digital recorder to
generate a serial time code, record it,
and also allow 2 channels channels (stereo) of simultaneous audio recording.
One pocket digital recorder I am looking at is the Olympus model WS-500
(~ 70$ at New Egg)
It may not have "Time-Nut" (10 to the minus 12) accuracy but it would
serve
my purpose when recording/logging satellite QSO's in a portable
operation with
a hand held full duplex, dual band walkie talkie and a hand held/pointed
dual band yagi antenna.
Audio receive from the satellite downlink would be fed into one audio
channel
and uplink audio would go to the other audio channel.
I could also live with only one audio channel for the downlink.
On playback the recorder indicates actual time of the recording being
played back.
After the satellite pass, transcribe the recoded info, or archive it in
a digital file.
The digital recorder is pocket size allowing hands free operation.
One hand to operate the transceiver and the other hand pointing the antenna.
I have not bought one yet, but I suspect the archived audio file would
allow time stamping to be played back in the common PC media player
applications.
Is the serial time code IRIG-A/B/C ? maybe not, but I can live with
the existing time code format..
Stan, W1LE Cape Cod FN41sr
On 12/3/2010 7:28 AM, Collins, Graham wrote:
On another list to which I subscribe, the question was asked about the
suitability of recording WWV 2.5mhz audio as one track when recording
off the air signals of interest as a time reference.
The person who asked the question didn't really state his intentions but
they seem very similar to my immediate needs. That is, simply a time
reference - that is "the time", the start of the minute, and periodic
references (i.e. seconds) between the announcements.
It seems that recording the audio of something like WWV or CHU is ideal.
However, another approach would be recording a more proper time code
signal as you might have available from a "precision clock". Of course,
a decoder would also be required.
A quick Google search turned up lots of leads which I have yet to sort
through. In the interim I thought I would pose the question to the
learned members of this group for their suggestions. Keep in mind KISS
and that a very high degree of accuracy is not required.
Is there an opensource/freeware PC app that will generate an appropriate
time code signal that can be recorded on one track of an audio recorder
(either PC based i.e. Audacity or standalone) that will also decode via
soundcard or other input?
Cheers, Graham ve3gtc
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Collins, Graham wrote:
On another list to which I subscribe, the question was asked about the
suitability of recording WWV 2.5mhz audio as one track when recording
off the air signals of interest as a time reference.
The person who asked the question didn't really state his intentions but
they seem very similar to my immediate needs. That is, simply a time
reference - that is "the time", the start of the minute, and periodic
references (i.e. seconds) between the announcements.
It seems that recording the audio of something like WWV or CHU is ideal.
However, another approach would be recording a more proper time code
signal as you might have available from a "precision clock". Of course,
a decoder would also be required.
A quick Google search turned up lots of leads which I have yet to sort
through. In the interim I thought I would pose the question to the
learned members of this group for their suggestions. Keep in mind KISS
and that a very high degree of accuracy is not required.
Is there an opensource/freeware PC app that will generate an appropriate
time code signal that can be recorded on one track of an audio recorder
(either PC based i.e. Audacity or standalone) that will also decode via
soundcard or other input?
Not free, but might get you started on what to look for
http://www.greenlake-eng.com/gle_tcsw_data_sheet_1-0.htm
Dave Mills and the NTP folks at U Delaware have
http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver6.html
for generators
http://www.wraith.sf.ca.us/ntp/index.html#test-tones
http://www.visualgps.net/NMEATime/default.htm $15, which is probably
cheaper than your time to write something or find something that already
exists and try to fix it.
If you move away from IRIG, there's also MIDI time code (used when we
used to record things on, gasp, analog magnetic tape, and you wanted to
keep the MPU-401 based sequencer running right), and various SMPTE
AES/EBU time codes used in the audio recording world.
I have used nematime over the years it does indeed work well.
I have not checked mine was win98 and I used it on an old laptop.
But it worked very well. Think I was using it for IRIG B which is an
excellant timecode for recording on an audio track.
On Fri, Dec 3, 2010 at 11:13 AM, jimlux jimlux@earthlink.net wrote:
Collins, Graham wrote:
On another list to which I subscribe, the question was asked about the
suitability of recording WWV 2.5mhz audio as one track when recording
off the air signals of interest as a time reference.
The person who asked the question didn't really state his intentions but
they seem very similar to my immediate needs. That is, simply a time
reference - that is "the time", the start of the minute, and periodic
references (i.e. seconds) between the announcements.
It seems that recording the audio of something like WWV or CHU is ideal.
However, another approach would be recording a more proper time code
signal as you might have available from a "precision clock". Of course,
a decoder would also be required.
A quick Google search turned up lots of leads which I have yet to sort
through. In the interim I thought I would pose the question to the
learned members of this group for their suggestions. Keep in mind KISS
and that a very high degree of accuracy is not required.
Is there an opensource/freeware PC app that will generate an appropriate
time code signal that can be recorded on one track of an audio recorder
(either PC based i.e. Audacity or standalone) that will also decode via
soundcard or other input?
Not free, but might get you started on what to look for
http://www.greenlake-eng.com/gle_tcsw_data_sheet_1-0.htm
Dave Mills and the NTP folks at U Delaware have
http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver6.html
for generators
http://www.wraith.sf.ca.us/ntp/index.html#test-tones
http://www.visualgps.net/NMEATime/default.htm $15, which is probably
cheaper than your time to write something or find something that already
exists and try to fix it.
If you move away from IRIG, there's also MIDI time code (used when we used
to record things on, gasp, analog magnetic tape, and you wanted to keep the
MPU-401 based sequencer running right), and various SMPTE AES/EBU time codes
used in the audio recording world.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
paul swed wrote:
I have used nematime over the years it does indeed work well.
I have not checked mine was win98 and I used it on an old laptop.
But it worked very well. Think I was using it for IRIG B which is an
excellant timecode for recording on an audio track.
I think it kind of depends on what's going to "ingest" the recording later.
In the lab world I'm in, IRIG and NTP (as well as 1pps/10MHz) are
natural choices.
However, if you wanted to do some processing with, say, matlab or
octave, it might be nice to have something where you could take a .wav
or .mp3 or similar file, load it in, and then have a utility that could
"time tag" the samples (i.e. say you had two channels of audio samples,
and after processing, you'd have 1 channel of audio samples and 1 column
vector of "time")
Or, given that there are lots of inexpensive high quality digital
multichannel recorders out there, something where you could feed your
timecode into one channel of the recorder, and record whatever you want
on the other 3,7, etc channels. Dump it out in whatever the native
format of the recorder is, and load it into matlab,c, whathaveyou.
Some of the digital recorders do timestamp the files in some way, but it
seems that it's always in some form that is convenient for audio/video
editing packages or media players. I've not found (I haven't spent huge
time looking) a matlab or c ingest program that takes a "media player
target" file and generates raw samples for manipulation.
I've got some iPhone/iPad apps that do things like record the
accelerometer data and will email you an excel spreadsheet with the GPS
(including time) and accelerometer readings. While that's not exactly
my preferred data format nor my preferred way to get the data out, it's
not bad.
WWV is not necessarily audible at all times. 2.5 MHz seems a poor
choice because it has 1/4 of the power at the higher frequencies,
except 20 MHz.
I went through a phase of acquiring Datum time code generators back
in 2003. Thought I'd turn them into rack-mounted shack clocks, but
never got around to it. These things generate and receive most IRIG
frequencies, but IRIG B at 100 HZ is the most commonly used.
They come in 1, 2, or 3 rack units height. They're built with late
seventies parts on plug-in cards and weigh about 15-20 pounds. Some
have crystal ovens at 1 MHz. Most can use an external 1 MHz. You
have to preset the time of day and push a start button after a
power cycle.
Also have some IRIG clocks, which only decode an IRIG signal.
I'd like to get these units to people who can use them, so shipping
is going to be the main cost. Don't know what it takes to ship to
Canada.
Bill Hawkins
bill@iaxs.net
-----Original Message-----
From: Collins, Graham
Sent: Friday, December 03, 2010 6:28 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Time Code generator
On another list to which I subscribe, the question was asked about the
suitability of recording WWV 2.5mhz audio as one track when recording
off the air signals of interest as a time reference.
The person who asked the question didn't really state his intentions but
they seem very similar to my immediate needs. That is, simply a time
reference - that is "the time", the start of the minute, and periodic
references (i.e. seconds) between the announcements.
It seems that recording the audio of something like WWV or CHU is ideal.
However, another approach would be recording a more proper time code
signal as you might have available from a "precision clock". Of course,
a decoder would also be required.
A quick Google search turned up lots of leads which I have yet to sort
through. In the interim I thought I would pose the question to the
learned members of this group for their suggestions. Keep in mind KISS
and that a very high degree of accuracy is not required.
Is there an opensource/freeware PC app that will generate an appropriate
time code signal that can be recorded on one track of an audio recorder
(either PC based i.e. Audacity or standalone) that will also decode via
soundcard or other input?
Cheers, Graham ve3gtc
apropos of the conversation
I seem to recall someone having built a PIC or Arduino based widget that
was a IRIG generator/receiver.. you'd hook up an external 10 MHz
source (something that any time-nut would certainly have.. the problem
would be selecting which one to use). I think it used a USB or serial
port to do the "control" function (i.e. setting the time or returning
the decoded time)
I also ran across a real small FPGA implementation about a year ago, but
I can't find it now. I was looking for a decoder I could drop into a
Xilinx design to be an "enhanced" 1pps sort of thing.
You computer can generate "time code" audio signals and if you are
keeping the computer's clock sync'd with NTP then those generated
time codes will be reasonably accurate. The time code generator is
distributed with the NTP software along with other misc. tools. It's a
free download if you don't have it. The code is I think the same as
sent by WWV. It is some IRIG version. It hing the name of the
time code generator is just "tc". There is a good chance you
alreasy have this but if not it's in the NTP source distribution
OK I just looked it up. The filename is .../util/tg.c and here is a
quote from the file
- This program can generate audio signals that simulate the WWV/H
- broadcast timecode. Alternatively, it can generate the IRIG-B
- timecode commonly used to synchronize laboratory equipment.
later NTP can read back this time code and sync a clock to it.
We do this "all the time" when recording rocket telemetry at
work. It works pretty much exactly the way the OP wanted
I thing this implementation in tg.c is good to about
1 millisecond
--
Chris Albertson
Redondo Beach, California
When audio/video time code is specified if its on a audio track its called LTC or Longitudinal Time Code and is generally IRIG-B, This is very uncommon these days as it went out of common use about the time 1" reel to reel was discontinued.
Most common today on NTSC is VITC or vertical interval time code. Its encoded as a series of pulses in the vertical blanking interval. The display is generally called a 'Screen Burner'
Sent from my Verizon Wireless BlackBerry
-----Original Message-----
From: "Collins, Graham" CollinG@navcanada.ca
Sender: time-nuts-bounces@febo.com
Date: Fri, 3 Dec 2010 07:28:13
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: [time-nuts] Time Code generator
On another list to which I subscribe, the question was asked about the
suitability of recording WWV 2.5mhz audio as one track when recording
off the air signals of interest as a time reference.
The person who asked the question didn't really state his intentions but
they seem very similar to my immediate needs. That is, simply a time
reference - that is "the time", the start of the minute, and periodic
references (i.e. seconds) between the announcements.
It seems that recording the audio of something like WWV or CHU is ideal.
However, another approach would be recording a more proper time code
signal as you might have available from a "precision clock". Of course,
a decoder would also be required.
A quick Google search turned up lots of leads which I have yet to sort
through. In the interim I thought I would pose the question to the
learned members of this group for their suggestions. Keep in mind KISS
and that a very high degree of accuracy is not required.
Is there an opensource/freeware PC app that will generate an appropriate
time code signal that can be recorded on one track of an audio recorder
(either PC based i.e. Audacity or standalone) that will also decode via
soundcard or other input?
Cheers, Graham ve3gtc
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
scmcgrath@gmail.com wrote:
When audio/video time code is specified if its on a audio track its called LTC or Longitudinal Time Code and is generally IRIG-B, This is very uncommon these days as it went out of common use about the time 1" reel to reel was discontinued.
IRIG is uncommon in the audio/video industry, but still used in the
telemetry and lab environment (IRIG is the Inter-Range Instrumentation
Group, at White Sands Missile Range, after all). I confess I doubt
anyone is still using magnetic tape with FM subcarriers on the range
these days, but you never know.. government facilities tend to use
really old equipment for a long, long time since the accounting rules
don't use depreciation (you buy it once, and it's free after that),
there's limited capital budgets for replacement, but often labor is
available to repair/limp along.
At JPL, we use IRIG to transfer time around between racks, particularly
for things like MIL-STD-1553B monitors, which timestamp the bus traffic
to the nearest microsecond or fraction, sync'd by the IRIG input.
There's something really convenient about needing just one cable/fiber
to perform the function.
Audio LTC is encoded differently than IRIG.. Biphase manchester,
different bit stream, different time encoding, etc. Conceptually
similar though. Any programmable hardware that can generate IRIG can
probably generate LTC as well. OTOH, if you built your IRIG generator
out of discrete 7400 series TTL, you've got a lot of "white wires" to
convert to LTC.
Most common today on NTSC is VITC or vertical interval time code. Its encoded as a series of pulses in the vertical blanking interval. The display is generally called a 'Screen Burner'
Sent from my Verizon Wireless BlackBerry
-----Original Message-----
From: "Collins, Graham" CollinG@navcanada.ca
Sender: time-nuts-bounces@febo.com
Date: Fri, 3 Dec 2010 07:28:13
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: [time-nuts] Time Code generator