Re: Computer clocks.

Frank Reed (
Thu, 23 Jul 1998 14:54:32 -0700

On Wed, 22 Jul 1998 17:41:52 -0500 Dave Mullenix
<> wrote:

>I've used talking alarm clocks the same way and it's VERY convenient. 
>When possible, I prefer to use a cheap short wave radio tuned to WWV
>(2.5, 5, 10 & 15 MHz) or CHU (3.33 MHz) or some other time station
>because it's more accurate and you get seconds ticks.  But whatever way
>you do it, hearing the time is the way to go!

Carrying this a step further, it would be really useful if there were a
small battery operated device (audible clock) that would emit audible time
codes that could be used while recording voiced comments into a
microcassette recorder while observing.  Though it's unlikely such a thing
can be bought, perhaps it could be built from various modules available for
DIY electronics buffs from Radio Shack, Circuit Specialists, and similar
suppliers.  It might be used as follows:

     The audible clock would be mounted on a shoulder strap 
     along with a microcassette tape recorder running in voice activated
     mode.  The satellite observer wears these on his shoulder much 
     like some security officers wear the microphone of their portable 
     2-way radio.  The purpose of the audible clock is two-fold, 1) the
     observer can monitor the time audibly, 2) the time codes are recorded
     in the background by the microcassette recorder as the observer 
     records spoken comments.

Question: does anyone know if there is a standard format for audible time
codes that would be suitable for this purpose.  Some of the desirable
attributes of the code would be:

1.  A user could easily learn to "understand" the codes as he hears them,

2.  User can easily discern time to a resolution of one second or less,

3.  Frequent ambiguity resolution.  See explanation below.

4.  Recorded audible signal plays back with little degradation.

By frequent ambiguity resolution, I mean that on playback of a short
recorded segment of the time code the user can establish the date and time
when the recording was made.  For example, if the recording was made by a
voice activated microcassette recorder, each recorded segment may be only a
few seconds in length - the time code recorded (and discernible on
playback) within each segment should probably contain enough information so
the user can determine the minute and second of the hour.  Hour of day, and
day of year information would be useful as well, but can probably be
established by other means.
Some of the coding formats I know of, and their deficiencies for this
purpose are:

1.  WWV broadcasts at 2.5, 5.0, 10 MHz, etc. contain seconds time ticks
with voice ambiguity resolution at one minute intervals (as I remember
them) - the ambiguity resolution is too infrequent,

2.  Morse code numeric characters are probably too long (the numeral 0 is
five dashes) to be useful in establishing ambiguity resolution often enough,

3.  Talking clocks I know about don't give resolution to seconds.

I was wondering if there were codes using combinations of tones of
different pitch and rhythms to encode time of day might be in use.
Examples that come to mind are the Big Ben chimes and ship's bells, but
these obviously don't have adequate resolution for this purpose.  Are there
bugle calls that encode numbers?

- Frank

-- Frank Reed
Scottsdale, Arizona, USA  111.898W  33.484 N  1227 feet