$2,619.00 1980 US dollars? How much is it in modern USD? $26k?
I was waiting for someone to notice the invoice. In 1983 I was a newly minted Ph.D.working for a USAID program for $40K and I was not unhappy. A watchmaker paid good money for this and these were still used in the US
Omega Service Center until the mid 1990s.
Fascinating. I can't however picture in my mind how this is used. How is a time piece connected.?
I understand how you can get a beat frequency compared to a reference oscillator with an oscilloscope so this device must have competed with cheaper CRO's of the same vintage.
The way this works:
Two microphones, one inductive (which I ignore and is only used for timing quartz qnd tuning forks) and the other is aoustic for mechanical.
The lever on the right selects the function and LED scale. This reports daily rate error soen to the -2+2 range. In 1980; when quartz mass produced quartz could not keep time (think PC clock errors). So a lot went into this time reference.
The lever selects the function and LIFTS the scales via a chain drive to the correct position.
Error rates and beat error are relatively easy. Just picks up the sound when the escape wheel tooth locks on one of the two pallet stones.
An interesting factoid is that the balance does not have equal excursions on both halves of the oscillation. This was empirically demonstrated to us (but I forget how). And a beat error of less than .1ms does not have a significant impact; but over 5ms it can be dramatic. This has to do with delivering impulse (and it really is impulse) when the balance impulse is before or after it's center line with the pallet fork (which delivers the impulse).
Amplitude is the tricky part. It involves knowing the portion of the balance rotation that the balance jewel is in contact with the pallet fork. This is called lift angle and the purpose of the thumbwheel on the upper left is to imput the lift angle so the amplitude can be calculated. The signals are the sound of the pallet for hitting the impulse jewel on the balacne, and the sound of the escape wheel locking on the pallet jewel.
It may help to look and oscillograph of a watch tick. There are five distinct sounds.
It took some figuring to design a system that could precisely and repeatedly measure the intervals of these sounds.
Today, such instruments are a tenth of this size and there are even smart phone apps. But forty years ago this is what was required to produce accurate and reliable results.
Oh, and these automatically selected the correct beat count (Beats per hour). These range from the most frequently used (18,000 BPH/5Hz) to 36000 BPH; the higher beat counts being less influenced by external shocks because of the time intervals.
I much prefer this particular instrument to the Chinese instruments ($100), ar the newer Witcschi instruments ($3k USD and now required to hold an account). I have a couple as a back up although it is easy to repair the power supply. The only chip problems I had were chip creep. I think they gave a lot os space to vent heat.