Using Signal Express to Automate Analog Electronics Experiments

B.D. Brannaka, J. R. Porter, Engineering Technology and Industrial Distribution, Texas A&M University, College Station, TX 77843

Proceedings of the 2005 American Society for Engineering Education Annual Conference and Exposition,
Copyright . 2005, American Society for Engineering Education. Reprinted with the permission of ASEE

Introduction
It is well known that many undergraduate students, especially in engineering technology
programs, learn best through hands-on experience. Thus, when teaching analog electronics, it is
critical to provide the students with a meaningful laboratory experience. While this sounds
straightforward, it is often difficult to do in practice. Many analog electronics experiments can
be very time consuming. For example, plotting the frequency response of an active filter or
transistor amplifier requires that the students make multiple amplitude and phase measurements
of the input and output signals. This process can be tedious and the result is that the students
often only have time to characterize a device once. This means they do not have time to perform
“what-if” scenarios where they change out a component and see the effect. Thus, they are losing
a valuable education experience. In addition, if their data is wrong then they have no opportunity
to repeat the experiment, and as such have learned very little. To address the problem, we have
previously presented automated digital and analog measurement systems as a solution.1,2 For
example, using a LabVIEW program and GPIB (General Purpose Instrumentation Bus) instruments,
one can build an automated frequency response analyzer that will rapidly characterize the frequency
response of a circuit. Unfortunately, because the coding of this type of measurement requires a
substantial amount of time, the program and the measurement process is typically provided for the
student. So, while this method allows the students to characterize systems over and over, it removes
them from the design of the test and measurement process, again costing the student a valuable
learning opportunity. Recently, National Instruments released a new software product called Signal
Express. The package is a dedicated test and measurement environment where the individual can use
high-level signal sourcing and measurement blocks to build an automated measurement system
that will collect and present data in a graphical form. Like LabVIEW, the environment is
graphical, allowing users to place individual measurement blocks in a particular sequence.
Unlike LabVIEW, the environment has a very short learning curve so that students can rapidly
program their own tests. Thus, it is easy to use while still leaving the need to design the required
test in the hands of the student. In the Summer of 2004, the EET Program at Texas A&M evaluated
Signal Express and wrote two electronics labs based on it. It is currently being deployed in an electronics
lab andwill be used to see how students respond to this new measurement tool. In this paper, we will
discuss the use of Signal Express and present an example for use in an analog electronics laboratory.

Reader Comments | Submit a comment »