The old modulation monitor circuit formerly located at this page is obsolete and has been retired. I have literally fielded hundreds of questions about this circuit, however in the 7 years that the circuit has been available, no one has actually ever built it, probably due to its complexity.

Modulation Monitoring is an important function in any AM transmitting installation, be it commercial, part 15, amateur, informational, etc. The ability to accurately measure your modulation - and - to be able to listen to that modulation from a low distortion instrument is crutial if you are to put out a good sounding, loud AM signal.

In response to the numerous inquiries about modulation monitors, I, along with others have worked to produce an affordable, accurate, and highly functional modulation monitor as a commercial product. This product has many unique features, however one of my personal favorites is the display - showing both positive and negative modulation at the same time ! You can instantly know whether your audio is in the correct phase, and what your positive modulation relative to your negative modulation is. My 2nd personal favorite feature is the peak-hold, showing your last, most recent highest positive and negative peak.

The monitor will also read modulation up to 150% positive. There are many, many other features of this new unit. See the link below for more !

Please click here for more information.