SB-634 Question!!

[Glen Zook]

The SB-630 uses a synchronous motor clock.  The SB-634 uses a digital clock.  The Tymeter clocks in the SB-630 do slow down due to wear over the years and therefore lose time.  However, since most digital clocks of the era when the SB-634 was designed (1973) used the line frequency as the frequency standard instead of a crystal controlled circuit like today, they are very dependent on the line frequency just like the synchronous motor clocks.

In fact, a lot of the early low end frequency counters also used the line frequency as the frequency standard rather than a crystal controlled standard.  As such, those counters were OK for audio frequencies but not reliable for measuring r.f.

When crystal controlled frequency standards started becoming "standard" in clocks and "low end" frequency counters they often used 3.579545 MHz crystals that were designed for color televisions.

Glen, K9STH

Website:  http://k9sth.com


--- On Wed, 10/21/09, Emil Dular <wd4scz at AOL.COM> wrote:

Isn't that a synchronous motor? 60 cycle AC should run fine. Now if you were in Germany it'd take an hour to show 50 minutes. Or am I missing something?


      

-----------------------------------------------------------
Products bought, sold or traded here is the responsibility of the
parties involved.  This list and the City of Tempe are not responsible
for losses or misrepresentations of any kind.  Buyer beware!

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.aspx?list=HEATH
To post - HEATH at LISTS.TEMPE.GOV
Archives - http://lists.tempe.gov/archives/HEATH.html