Nice display Jim! But put it in the double side band position and reduce the carrier to -60 db or so and notice that you have exactly the same wave form as that of the SSB with carrier at -6db, which is equal to the side band energy in this case.
It is not the transmission of the single side band with carrier that gives the distortion but the envelope detector in the receiver. With only one side band and carrier the detector can't make up its mind which signal is supposed to be the carrier and which is the modulation when you have higher levels of modulation. The result is high levels of second harmonic distortion generated in the detector. As long as the modulation percentage is kept to a lower level the distortion is minimal and it sounds fine. If you use a receiver with a rather sharp filter and listen to a regular AM signal and tune off to one side (which is often done when heavy qrm is present) you generate the same kind of signal at the detector in your receiver. You greatly reduce one side band of the signal reaching the detector and it sees SSB with carrier. 73 Gary K4FMX > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:amradio- > [EMAIL PROTECTED] On Behalf Of Jim Tonne > Sent: Thursday, February 07, 2008 7:48 PM > To: Discussion of AM Radio in the Amateur Service > Subject: Re: [AMRadio] Re: Carrier with one sideband > > > Gents: > > First, this is my first post to this interesting group and I > hope you take what I have to say constructively. > > This business of SSB on AM, etc., is of interest to me > on a technical basis. > > But let's do a computer simulation of this thing. To > this end I have written a computer program which > allows you to select various AM modes and the > program then shows you the transmitted envelope > and the associated spectrum. > > It is temporarily posted here: > http://tonnesoftware.com/ModTutor.exe > > That file is just a barefoot executable without all of > the usual Window$ garbage. It should run on most > Windows computers. If not e-mail me and I'll make > a full-blown install routine. > > I am suggesting you download the program and > run it. Click on the opening screen option "Single > sideband" and then click on "Ideal lower sideband". > > See the transmitter output as a "carrier". Then click on > Carrier= 0 dB. Then on Carrier=-6 dB. Then on > Carrier=-12 dB. > > Not real pretty, is it? > > Now click on "Double sideband" and on Carrier=0 dB. > > I think the folks on this group will find the routine as > interesting as others have. > > - Jim WB6BLD > > > ______________________________________________________________ > Our Main Website: http://www.amfone.net > AMRadio mailing list > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:[email protected] > To unsubscribe, send an email to [EMAIL PROTECTED] with > the word unsubscribe in the message body. ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected] To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
