Ph / APh / EE / BE 118a




Physics of Measurement

Winter 2021











Lecture Notes


Assigned Reading


Additional Resources




05 Jan 2021


Welcome to Ph/APh/EE/BE 118a!

Our first class will be held online today, Tuesday, 5 January 2021, from 2:30-3:55pm PT. Please e-mail me at (roukes at caltech dot edu) if you did not get a zoom link by e-mail. The class syllabus is posted online at the link above.

This is the first time the class will be offered online, so please be patient... we're building this plane as we fly it!


Please note that all homework assignments must be submitted to the TA by e-mail; hard copies will not be accepted. If you wish to scan handwritten calculations and submit them for grading, a list of available scanners on campus can be found at this link.



Tue & Thu
2:30-3:55 pm

taught online


Course Info

  • Professor:   Michael Roukes, Frank J. Roshek Professor of Physics, Applied Physics, and Bioengineering / Office: Bridge Annex 131 / roukes at / webpage / wikipedia


  • Course Description:   This course will provide an introduction to concepts and principles of physical measurements that are crucial to experimental research. This is stuff that I want all of my students to know. Topics surveyed include signal domains and transduction, responsivity, backaction, physical noise processes, bandwidth and information, nonlinearity, frequency conversion, modulation, synchronous detection, signal sampling and time-domain methods, digitization, signal transforms, and multiple-measurement correlations. Where possible, examples will be formulated around current approaches providing state-of-the-art sensitivity. Possible examples may include quantum interference devices, bio/chemical sensors, photonic devices, and various micro- and nanomechanical systems, depending on time and students' interests.

  • Prerequisites:   APh105 or Ph127 or equivalent, and Ph105 or equivalent -- or the instructor's permission.

    This is a class for those embarking upon careers involving laboratory measurements.  It is primarily designed for beginning graduate students in the physical and engineering sciences, however others are welcome. The officially stated prerequisites are Analog Electronics (e.g. Ph105) and Statistical Mechanics (e.g. APh105 or Ph127) …  but I’ll say, unofficially, there are no prerequisites but the desire to learn and a willingness to ask questions in class.  However, in my lectures I’ll assume you’re familiar with basic circuit theory and electronics, as well as Fourier analysis, auto- and cross-correlations, and concepts like spectral densities, etc.  You’ll probably find it a hard go without some knowledge of these.  With sufficient interest, our TA may schedule a tutorial or two on such topics.  Additionally, the class will make a whole lot more sense to you, and be of obvious relevance, if you’ve already had some exposure to laboratory research involving hands-on physical measurements. To register, undergraduates must be working on laboratory research, and must provide a letter of support from their experimental research advisor.


  • Units:   9 units (3-0-6); first, second, third terms.

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