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# Physics/frequency measurement

Question
Dear Sir,
In the early stages of telecommunications and electronics, how did they measure the high frequency?, for example, how did  they count frequencies of an oscillator circuit  above 1 Khz?. Even if the frequency would be 100 Hz,  I canīt imagine any electro mechanic device to do this.

Hello miguel,

See additional info added at the end.

I haven't been able to find a definite answer for your question. Perhaps a way to measure frequency would have had to wait for an early oscilloscope. Then they would have to count pulses on the waveform within the horizontal grid that represents 1 second (or 1 s/10 or 1 s/100 etc.). If so, accurate timing the rate of the horizontal sweep would probably have involved a quartz crystal.

Alternative methods that I have no experience with involve an absorption wavemeter
http://en.wikipedia.org/wiki/Absorption_wavemeter
or a wavemeter based on a resonant cavity

I have submitted a request to the website
http://www.tf.nist.gov/general/museum/847history.htm
for help on your question. If I get a reply with applicable information, I will edit my reply to you. Allexperts.com will then notify you to check my answer again.

I hope this helps,
Steve

P.S.

The request to the nist website yielded images of 6 pages from a book that they had. The 6 jpg files are in the album that the link will take you to.
http://s131.photobucket.com/user/tjsail/slideshow/wwv
Questioner's Rating
 Rating(1-10) Knowledgeability = 8 Clarity of Response = 9 Politeness = 10 Comment May be, they didnīt measure directly the frequency but they deducted it from the formula of frequency for LC resonators(f = 1/ 2 *pi + (L * C ) ^1/2) . Thanks.

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Physics

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#### Steve Johnson

##### Expertise

I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

##### Experience

I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

Education/Credentials
BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University