[time-nuts] Got 60HZ?

[Bill Hawkins]

Have one of those FAA signal generators of vacuum tube vintage.
There's a selector switch for about a dozen frequencies that
mechanically moves the light detector to the right track.

The eddy current brake was used in a synchro system to adjust
the speed of the control transformer shaft, which generated
the three-phase signal for rotating the antenna and all of
the radar display sweeps. The electromagnet is quite large.

A Hammond tone wheel might get you eight octaves of harmonics,
or 2**8. No need for decayed dividers and their reset tricks,
just straight flip-flops, all the way down.

Bill Hawkins


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Robert Atkinson
Sent: Saturday, December 11, 2010 12:57 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Got 60HZ?

Ahh,
the tone wheel. make it a shaped slot, lamp and LDR and you can have a
sinewave. Add a second sensor on an arm pivoted at the center of rotation
and you have variable phase. A lot of early aircraft test signal (VOR / ILS)
generators used this technique. metal disks and eddy current sensors were
more common than optical. There was also the Hammond organ.
If you want 50Hz clocks try ebay.co.uk or amazon.co.uk etc. Or I can supply
for a small commisson ;-)
 
Robert G8RPI.