In the past thirteen issues of the EDA WEEKLY by this writer, there have been two articles related to the task of “verification” involved in improving the speed and functional accuracy of complex electronic system designs, especially complete systems that can be engineered into semiconductor chips.
The first article posted April 26, 2010 was about EVE, the privately-held company that takes the approach to verification by providing hardware emulators and custom software to rapidly validate that a specific silicon integrated circuit design performs its desired functions correctly, thus reducing re-spins or even eliminating re-spins entirely:
A second article appeared on October 11, 2010 about another privately-held Silicon Valley company called Real Intent, which develops and markets easy-to-use software products that verify, at the earliest opportunity in the design cycle, that a silicon chip’s design actually implements the designer's intent:
For this November 15, 2010 issue of the EDA WEEKLY, we switch to the issue of designing the electronic system for a chip in the first place.
No, we’re not going to discuss the well-understood, and now considered classical approaches to designing purely digital chips using models written in well-known “hardware description languages” (HDL’s) such as Verilog or VHDL (although the effective use of HDL’s still calls for specialists). Nevertheless, after years of use, a whole bevy of EDA tools and products exists to support the purely-digital chip design process.
Rather, we will attempt in this article to discuss the far more difficult job of designing and verifying an analog chip, or worse yet, a chip that mixes analog and digital signals. According to one Dr. Martin Vlach, “It is probably safe to assert that no truly general methodology has yet been adopted to design and verify analog and mixed signal (AMS) chips.” And since Dr. Vlach originated the well-known SABER Simulator (A) and MAST HDL (B), he should know!
Note: Capital letters in parentheses and numbers in brackets refer to Definitions and Footnotes, respectively, included at the conclusion of this month’s EDA WEEKLY.
Accordingly, after some basic introductions, we will discuss in this article the use of relatively new, alternative EDA tools for modeling and simulation of analog and mixed-signal electronic systems accomplished by replacing traditional HDL-based coding approaches with a unique graphical method.
And as you have surely guessed by now, these relatively new, alternative tools come from a nine-year-old, privately held company improbably named “Lynguent.”
We’ll explain later how the company name originated.
As you proceed through this article, your recollection of the differences between “analog” and “digital” will soon resurface. You’ll recall, for example, that a signal transmits data of some kind. An analog signal may be thought of as a continuous wave of various amplitudes vs. time that almost always contains multiple frequencies. The earliest telephones used analog signals to transmit the human voice:
Digital signals are different; they look like this in the simplest form:
Digital computers use such signals. Although digital signals can only be in the state 1 (on) and 0 (off), complicated combinations of these two values are used to send/receive data. Think of this example: Using only binary (values 1 and 0), we can create a string of values that can be interpreted by a digital computer to be something more meaningful. For instance, the value 11000110 00110101 10010011 00101101 is interpreted to equal 184.108.40.206 in decimal format.
Since the real world of humans deals in analog signals, and digital computers use digital signals, there is a tremendous need for devices that convert analog to digital. Electronic designers might use this symbol to denote an “analog to digital converter” (or “ADC”) shown below:
...and a similar device to convert digital signals to analog would have a similar symbol.
An actual physical realization of such a device might look like this (and probably would be much smaller in size these days):
A 4-channel stereo multiplexed analog-to-digital
Converter placed on X-Fi Fatal1ty Pro sound card
Location of Lynguent HQ
Surely such an innovative firm as Lynguent is located in the heart of Silicon Valley, nicht wahr? Nein, nein, mein Geschäftsfreund!
Lynguent Headquarters are in fact located precisely 623 miles north of the writer’s Albany CA office by automobile, in beautiful downtown
Portland, OR, a healthy stone’s throw from the Willamette, the well-known river that runs through the center of The City of Roses:
The Willamette River is also evident in this Wikipedia photo.
The Albany CA to Portland OR driving time is approximately 9 hours (over 87% of which is on I-5). Why, en route from CA to Lynguent HQ, one drives right past Mentor Graphics’ HQ  in Wilsonville, OR:
Mentor Graphics Wilsonville HQ
After another 18 miles from Wilsonville, at the end of the journey north to Oregon we finally arrive at Lynguent Headquarters in downtown Portland:
Lynguent Corporate Headquarters in Portland, OR