We've been beating this DEAD horse. Don Chester made some very good points regarding the way human process audio presented to the ear.
Some may disagree. The reality is just what Don stated. The consonants do indeed appear up around 3500cps. If one were to have an audiogram, hearing test, performed, you would be amazed what your actual hearing span is. I am pushing right at 60 yrs old. I STILL get the 15Kc sound in my ears whenever I pass by a TV. The rules and regulations, Part 97, list the Emission as A3E. Regarding that, there is NO question! Then there is the VERY real reality! I look at the audio chain in MY transmitters. I suspect many would find "very similar" specifications. The audio transformer that takes the output of the first audio amplifier stage, lists clearly on its label: 400 to 3500 cycles. This already demonstrates that the bandwidth is 100cps over the 3,000cps. Now when you lay it out in a graph or on a scope, the carrier sits in the middle. Each sideband is offset from the carrier by the lowest audio frequency passed. In my case the carrier stands alone with 300cps open on each side of it. That is where the sidebands start. Then take the width of audio chain response, and you have each sideband 3100cps in width. Now, add the entire width. 3100cps, a 600cps gap with the carrier in the middle, and another 3100cps. This makes the entire signal 3100+600+3100. IOW, 6800cps in total width. Unless the top 400cps is trimmed off or filtered down, you absolutely cannot stuff it into a 6000cps width signal! I am posting this as a little more comprehensive view of AM DSB. The entire discussion has concentrated on a 3000cps sideband audio. Yet it hasn't been presented as the ENTIRE signal as it looks like and IS. This is MY $0.02 worth, but I feel it needs to be laid out as it is. AM is indeed structured in this manner. Bob - N0DGN ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
