What CEH invented after Beta 21
among other things, a Beta 4 movement for Piaget
The familiar story about Switzerland’s Centre Electronique Horloger (CEH) stops abruptly at the 1970 Beta 21 (better understood as Beta 2.1), the first commercialized Swiss quartz movement.
The beginning is clear enough. Cara Barrett writing during Hodinkee’s turbulent 2015 ‘quartz week’ sets out the collective memory1 :
the major Swiss watch brands caught wind of this new technology and approximately 20 maisons (including Omega, Piaget, and Patek Philippe) created the Centre Electronique Horloger (CEH) in 1962 in Neuchâtel. The purpose of the C.E.H. was to focus on researching, creating, and producing a
quartz[electronic] movement efficient enough, reliable enough, and accurate enough for the next generation of watchmaking.
Beta 21 watches are cool enough, and the movement famous enough, that the cal. 2510 inside the AP 6001 is almost universally misidentified by dealers as a ‘Beta 21’ (it’s an Omega Megaquartz). Patek may have even commercialized the first ‘true’ TV dial2 watches with Beta 21.
Flipping through backissues of Europa Star (e.g. 1978, photos below), it is clear that the 1970s saw an explosion of post Beta 2.1 non-Japanese quartz watches, rivaling today’s explosion of independents. With so much excitement at that time, I once presumed that every horological engineer at CEH was soon poached by individual brands.
However, before becoming part of CSEM in 1983, CEH continued to operate and produced at least one more historically significant quartz movement.
Although trivial relative to the scientific discoveries made at CEH3 (this being a watch Substack), that movement is the focus of this article.
This is part of a series on the technical history of quartz watches, cataloged here.
Dr. Eric A Vittoz
Dr. Vittoz is a Swiss giant in high technology. His entry in the Engineering and Technology History Wiki says:
A renowned expert in low-power CMOS circuit design, Dr. Eric A. Vittoz also is recognized for his groundbreaking work with miniature electronic devices. His contributions at Centre Electronique Horloger (CEH) in Neuchâtel, Switzerland in the early 1960s advanced the development of the first electronic wristwatch. His work has fueled innovations including low-voltage CMOS logic; circuits based on MOS transistors operated in weak inversion, as bipolars and as pseudoresistors; and biology-inspired processing. With colleagues at the Swiss Federal Institute of Technology (EPFL) in Lausanne and CEH, he developed a MOS model for low-current and low-voltage circuit design known as the EKV model. His work has been applied to a wide range of battery-operated instruments. Dr. Vittoz is Research Fellow at the Swiss Center for Electronics and Microtechnology in Neuchâtel and a professor at EPFL. An IEEE Fellow, he has published more than 130 papers and holds 26 patents.
An IEEE review of those early days of unclassified microelectronics says that, “in May 1962, Dr. Eric Vittoz was the first electrical engineer hired by” CEH.
Dr. Vittoz’s online C.V. indicates that he worked at CEH/CSEM until 1984, extending the timeline of CEH’s existence as a functioning research center for 14 years after Beta 2.1.
There was a Beta 4
To answer the question of what CEH did after 1970, then, we can look into the writings of Dr. Vittoz and colleagues with a high degree of confidence.
With the $30-odd billion/year Swiss watch industry (and its industry associations) no longer in the habit of making historical documents available to the public internet, we are forced to refer to a Japanese translation of a French paper by Vittoz and colleagues, “Instant Self-Adjusting Electronic Watch”, presented to the 1974 Congrès International Chronométrie (CIC):
Co-authors Walter P. Hammer and Henri J. Oguey4 are no less significant in the history of Swiss quartz (which is to say, of Swiss high technology), but that is a story for another day.
Presented was an automated and contact-free way of re-regulating a quartz watch, i.e. to correct for aging.
Abstract:
Adjusting the rate of an electronic watch by digital means makes it possible to eliminate trimmers and to freely widen the [manufacturing] tolerance of the crystal. This principle also makes it possible to provide the watch with a rate reference and to adjust it completely automatically based on that.
Here, we will explain a watch system that makes use of this possibility, examining its logic mechanism and main components. The frequency of the crystal is about 500KHz. Adjustment is performed in less than 2 seconds using a very simple device on which the watch is simply placed.
To summarize the paper,5, the watch listened to a regulation reference device via a wireless coil. The regulation reference, to be installed in a jeweler’s shop, merely gave steady magnetic pulses (‘Référence de réglage’), which the watch wirelessly sensed, figured if it was slow or fast, and digitally corrected itself to.
To do this required a break from the 500-year old ‘classical’ paradigm of clocks and watches to that point (including balance wheel, tuning fork and quartz), which is a fixed ratio between the oscillations of the regulator and the rate of the watch.
In mechanical and tuning fork watches, this ratio is embodied in the geartrain. In classical quartz, by the cascade of electronic dividers. But Figure 2 of the paper I call Vittoz (1974) contained a revolutionary ‘diviseur ajustable’, with the citations dating the invention further back to 1971!6
This adjustable frequency divider, or in other literature, variable frequency division, is what enabled the cool automatic regulation feature, because the circuit itself controlled, very finely, what the ratio could be.
It also happened to open the door to a future of economical quartz, already hinted at in the abstract’s allusion to tolerance, although that future was yet a decade away.
The frequency was unusual, nominally half a megahertz (2^19 Hz).
By choosing a frequency of about 0.5 MHz for the oscillator, one can produce a very small, simple and robust crystal, with a circuit consumption of a few microamps without resorting to critical technologies.
The tolerance of the crystal has been widened to ±1.5% in order to eliminate all crystal adjustment operations.
The figure 532 kHz ±1.5% corresponds exactly to 2^19 Hz -0%/+3%.
A frequency divider consisting of 19 binary steps provides a 1Hz signal suitable for step motors and electronic displays.
These 19 steps can be adjusted by 2^-19 steps to a ratio corresponding to an adjustment accuracy of nearly 0.1 seconds/day. The length of the adjustment cycle (note 1) is equal to the output period, so all these periods are strictly the same. 14 adjustment bits, i.e. 14 memory bits, are required to obtain a limit of 3% of the full width.
The reference period provided to the watch by the regulator must be exactly 1 second (with an error of 1 µS).
The ‘reference’ device was shown both schematically as the ‘primaire’ and, tellingly for the fate of this invention, in a photograph:
The photograph shows a large boxlike gadget, probably adapted from a highly stable marine chronometer movement, with a watch on top of it.
Commercialization by Piaget
The paper concludes with, “A commercial product based on this system is currently under development in cooperation with Piaget, Switzerland.”
