I wish to thank Paula Ochs and Pat Green for help with this story.

From the perspective of electronics, God presented mankind with a digital world. The smallest resolution element is the charge of an electron. It takes 6.241X1018 electrons to pass a given point to generate one ampere of current.

The R7912 used a dual beam cathode ray tube (CRT).  One end of the CRT was signal acquisition which had a bandwidth of up to 3Ghz.  The other end was used to scan the target of the acquisition beam.  A diode array storage target was in between the two beams.  All instruments using an electron beam, as in a CRT, had “trace blooming” when signal levels were high enough.  During my employment at Sandia Laboratories in New Mexico, I used microdensitometry, under the direction of Dr. Gilbert Cono, to digitize photographs from nuclear events to find the center of trace.  Analysis software required a single y-axis value for each x-axis value.  The R7912 provided two addresses for each time location, one when the diode array target draws 9X10-9 amperes and when there is no target current as the scan beam pass over the target.  The average of the two was used to find the center of the trace.  Sometimes there was a defect in the diode array target and it was necessary to interpolate the center of trace through the defect area.  Three points were used to continue the trace through a defect area, providing the computer analysis with the most accurate information.

A Digital Equipment Corporation (DEC) PDP 11/23 computer was used to control the R7912 at its introduction in the fall of 1973.  These computers were more compatible with mobile operations of our customers, in contrast to a mainframe such as an IBM.  The R7912 had a CP-Bus for digital output (the R7912AD changed to the industry GPIB interface).  One issue with the CP-Bus was that it limited the number of R7912's to eight.  Another computer interface was CAMAC used by high energy laboratories such as Fermi Labs near Chicago, Lawrence Berkley Labs in California, Serum High Energy Labs in Europe.  This interface was not limited to eight units.  We also received requests from the field for time-domain-to-frequency-domain conversion capability.

Before the R7912, Tektronix had produced the Digital Processing Oscilloscope (DPO).  It separated the CRT display and signal acquisition with an analog/digital unit, the P7001.  I believe the array from the DPO P7001 was from a successive approximating analog to digital converter.  Use of the DPO was facilitated by a software package developed by Bruce Hamilton's team and a signal processing consultant from Oregon State University, Lyle Ochs.  DPO TEK Basic ran on a DEC computer and used a GPIB link to communicate with the DPO.  I believe this package was the first to provide an FFT (Fast Fourier Transform), which was designed by Lyle Ochs (Lyle joined Bruce Hamilton's group as manager of the signal processing team in 1974).

There are few engineers who can take a set of complex math equations and make it into a real world tool, as Lyle Ochs did with the FFT. This is one of the key signal processing functions, since it converts signals from the time domain to the frequency domain. It is described in “The FFT Fundamentals and Concept”’ (070-1754-00), authored by Robert (Bob) Ramirez in 1975 (I believe Bob was mentored by Lyle).  Bob also produced a book by the same title which was published in 1985. This FFT was based upon the algorithm Sande-Tukey as a subset of the algorithm published by Cooley of IBM Watson Laboratory and Tukey of Princeton University (1965) which describes decimation in the time domain. Sande-Tukey describes decimation in the frequency domain. Even today this algorithm is used in a wide variety of applications. I personally know it is used in nuclear events analysis, bearing monitoring in generators at Grand Coulee Dam, weld joints in nuclear reactors, spinal cord regenerations, development of optical time domain reflectrometry (OTDR) in fiber cables, pulse laser signal analysis, among others.

WDI TEK Basic was an augmentation of DPO TEK Basic to allow the R7912 to be controlled and its data processed.  WDI was really a “stop gap” measure.  It was realized that there needed to be a more generalized solution than this, allowing for new digital products to be controlled without the overhead of developing a unique new software system for each one.  Bruce Hamilton and his new software manager, Don Williams, started laying out plans for such a “generalized solution.”

Next was the problem of how to fund such an engineering effort.  This was probably being worked on in the spring of 1974.  Some of us in the Marketing Department, together with Bruce and Don, came up with an estimate of $500,000 (IIRC) for a product proposal.  At this time, any product proposal at Tektronix had to be approved by President Howard Vollum.  It became my task to present this proposal to Howard and the Senior Engineering staff.  I am not sure who else was at this meeting.  It could have been Bob Hightower, David Nelson, Dr. Jay Snell or Robert Johnson, all from Marketing, and Bruce Hamilton and/or Don Williams from Engineering.  I was not used to presenting a product vision without any hardware to show.  Placing a reel of magnetic tape on the table was, obviously, not an option!  We had put together a written proposal, which included an outline of major features, and this is what I presented.  I am sure several Field Engineering reports were included since Howard was an avid reader of these notes.  He also had a good grasp of the primary markets for the R7912, namely nuclear events and laser measurements.  The day arrived for the meeting in the Building 50 fourth floor conference room.  After answering several questions from Howard and other managers, such as John Gates and Bill Walker, we remained seated when Howard and the senior staff left.  I asked, “Did we get approved”?  I believe it was Bruce Hamilton, having probably been through this process with DPO and WDI TEK Basics, who said, “Yes.  When Howard stops asking questions, it is approved.”

The software system approved that day would come to be called SPS TEK Basic (Signal Processing Systems TEK Basic).  Paula Ochs, reporting to Don Williams, led the team that developed the software.  Engineering details are left to them or others to provide.