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 Episode 42 - Life, the Universe, and Radiometry?: Play Now | Play in Popup | Download (571)

This is our latest podcast on the subject of Radiometry. It has been awhile since our last podcast, and in this podcast I explain what is going on. I recorded this twice, and used footage from both attempts, but I am not perfectly happy with the result, but it has been awhile so I decided to put it up anyway.

The first two volumes of our measurement series have just been published:

• Volume 1 - Introduction to Measurement Concepts and Measurement Uncertainty
• Volume 2 - The SI System of Units

These are the first two books in a series of eight books that we are planning to publish, built primarily from our online material.

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 Episode 41 - S-parameter Measurements: Play Now | Play in Popup | Download (1037)

In this episode we go over some basics S-parameter measurement. These include a description of a type of directional coupler, the basic concept of how to represent a reflectometer as a two-port device, and finally how to calibrate the associated model parameters using an open short and load. The measurements of a two-port device are then briefly discussed, by adding a through measurement to the calibration. Isolation terms in the calibration are not discussed.

This episode has a few mistakes in it, but those were basically corrected by putting notations on the video. I didn’t want to reshoot a third time to correct them.  This episode is heavy on the mathematics of reflectometer calibration, and gives approximate calibration equations that one could use if they wanted to construct their own reflectometer. What is not covered is that there are some problems that need to be considered. The main idea shown here is that it is possible to compensate for errors in a reflectometer or network analyzer with some simple measurements of an open, short, and load.

The following course has been added to the course catalog

• MEAS463 - Introduction to MIL-STD-461 RS Measurements

This is the fourth of a series of four courses on MIL-STD-461 measurements. The topic of this course is radiated susceptibility, or RS measurements.

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 Episode 40 - S-parameters: Play Now | Play in Popup | Download (1123)

This is the first in a series of podcasts on the subject of RF and microwave measurement. In this episode we reintroduce S-parameters, and give some of the basic equations for cascading a two-port and a one-port or two-port. S-parameters come from a concept that was borrowed from particle physics by electrical engineers to solve the problem of propagation of RF signals through a network. A network is anything that has ports where signals can be input and output, if there are N of these ports, there are N² of these S-parameters.

If there is an wave amplitude input at port n of a_n, and and output of wave amplitude b_m at port m, then

S_mn = b_m / a_n

There were several courses introduced into the LearningMeasure.com course catalog since the last podcast. These are

• CPROG101 - Introduction to the C Programming Language
• INST404 - Amplifier Types and Specifications
• MEAS462 - Introduction to MIL-STD-461 CS Measurements

If these, or any of the other courses in our course catalog, interest you, please register as a student and subscribe. It is your subscriptions that keep this podcast going!

As always, let us know if there is any topic you want to see covered on the podcast, or if there is any course you would like to see developed.

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 Episode 39 - Louis Parker: Play Now | Play in Popup | Download (892)

In this episode we do something a little different. We did our first interview using the Mac software iChat to do the interview remotely.

Louis Parker, the person interviewed in this podcast, is a member of the LearningMeasure.com consultant network, and is owner of Test & Measurement Consulting, LLC.

Louis has 20+ years in RF/Wireless with an emphasis on designing and testing short range wireless devices (RFID, Bluetooth, WiFi), RADAR and SATCOM transceivers. 6 years training engineers and account managers on RF technology and measurement (metrology) fundamentals as well as presentation, public speaking and sales skills.

This podcast has three sections, first a short interview with Louis, followed by a technical talk on the real behavior of circuit elements often thought as ideal, and finally some elaboration on the subject of oscilloscope probing.

If you would like to utilize Louis Parker’s services as a consultant or for training, contact him through his website, or you can contact us here at learningmeasure.com and we will forward your request.
If you want to join our consultant network, register as a student, and then fill out a consultant profile. If you want to be on the podcast, email me at vendors@learningmeasure.tv.

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 Episode 38 - Gravity Waves: Play Now | Play in Popup | Download (865)

This is an episode about gravity waves and the Laser Interferometer Gravitational Wave Observatory or LIGO experiment. This was something requested by one of you, and here it is! I am also trying to get someone on the podcast who has something to do with this experiment in a future episode. So if you want me to cover some topic, let me know. This topic is a little out of my areas of expertise, but I hope this provides some sort of basic explanation for what is involved.

We also announce a new course CLP101 - Calibration Intervals. This is one of many courses that we plan to add in the Cal Lab Practice section of courses.

We need more feedback! Let us know if there is any topic you would like to see covered in the podcast, let us know. Also if there are any courses in particular you would like to see us to develop to meet your needs, that information would be appreciated.