Online Pitch source

[Jerry Cohen]

Scott,

What about using a cellular phone to call up NIST? Since the cell phone is
digital, does the accuracy depend upon the oscillator in the cell phone?

For that matter, what about a digital portable phone?

Thanks,

Jerry Cohen, RPT
NJ Chapter




Kerry Cooper suggested:

> Download Skype (VOIP) pay 10 euro's and dial +13034997111 and it will come
> through your speakers.

Unfortunately this is no better than playing a WAV file on your computer.
The VOIP method of accessing the telephone network introduces variable
network delays that make it necessary to reassemble the sound at the
receiving end according to the time-base in your computer.  The pitch of the
NIST tones will be distorted.  The VOIP protocol uses long-term rate
adjustment strategies to keep the data buffers from overrunning, but over
the short term, the playback rate is not guaranteed to be the same as the
recording rate.

Robert Scott
Ypsilanti, Michigan