Settings for NRSC Pre-Emphasis in VOLT AM

Updated 1 week ago by Mark Manolio

Scope

How to set the VOLT AM up for the "actual" NRSC Pre-emphasis curve.

Description/Problem

Q: I want to be sure that the Volt is providing the proper NRSC pre-emphasis curve for my AM transmitter.  I do not see anything to directly set the preemphasis.  Am I missing something?

Solution

A: The AM pre-emphasis is set using the HF-EQ Pre and/or Post controls in the INITIAL / ENHANCERS menu. So pre-emphasis can (uniquely to the Volt AM) be added before and/or after the MB limiters.

The "actual" NRSC curve is achieved with a setting of 10.00 dB. Either 10 on one control or a combination of the two that add up to 10, such as 5 & 5 or 4 & 6 for example.

Our "AM Guru" Ted Alexander wrote this when we were developing the Volt

With the Pre only, much of what was EQ'd up, was "taken out" by the limiter after just 3 or 4 db boost.  Using the Post only EQ, when I got closer to 10 db boost, the HF started sounding kind of "grainy". By applying about half (give or take several db) both Pre and Post, I was able to get a significantly better AM Pre-emphasis "sound".  As of today, I kind of like the way it sounds with 4db of Pre and 6db of Post. 

Here, it is set for 4dB Pre and 6dB Post:

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