Re: [Repeater-Builder] OT ACSSB - how does it work and is it possible for the hobbyist to scratch build
Have a look at http://www.kangaus.com/kk7b.htm At 01:50 11/12/2009 -0800, you wrote: This problem (generating the 90 degree phase shift audio) is all that is keeping me from an experiment to generate a SSB signal using a little known technique I ran across in an old QST. It seems that a phase modulated FM signal can be combined with amplitude modulation with the audio 90 degree phase shifted and generate a SSB signal. The experiments referenced wound up with a SSB signal with full carrier. My first foray into sideband operation back in the late '50s was with a command transmitter with the grids modified to push pull and applying push pull audio to the screens. This generated a double sideband suppressed carrier signal. I suspect that I could modify a GE Prog transmitter by rewiring the grids of a 60 Watt final to push pull and applying push pull audio to the screens and applying 90 degree phase shifted audio to the normal phase modulation input would generate a SSB suppressed carrier signal. I suspect the pre-emphasis in the phase modulation circuit would have to be defeated, or does a phase modulation scheme automatically generate the pre-emphasis? 73 - Jim W5ZIT --- On Wed, 11/11/09, DCFluX wrote: From: DCFluX Subject: Re: [Repeater-Builder] acssb - how does it work and is it possible for the hobbyist to scratch build To: Repeater-Builder@yahoogroups.com Date: Wednesday, November 11, 2009, 9:02 PM I was playing with the ideas of making adapters, but it is supprisingly difficult to throw audio exactly 90 degrees out of phase over a broad frequency range.
[Repeater-Builder] OT ACSSB - how does it work and is it possible for the hobbyist to scratch build
This problem (generating the 90 degree phase shift audio) is all that is keeping me from an experiment to generate a SSB signal using a little known technique I ran across in an old QST. It seems that a phase modulated FM signal can be combined with amplitude modulation with the audio 90 degree phase shifted and generate a SSB signal. The experiments referenced wound up with a SSB signal with full carrier. My first foray into sideband operation back in the late '50s was with a command transmitter with the grids modified to push pull and applying push pull audio to the screens. This generated a double sideband suppressed carrier signal. I suspect that I could modify a GE Prog transmitter by rewiring the grids of a 60 Watt final to push pull and applying push pull audio to the screens and applying 90 degree phase shifted audio to the normal phase modulation input would generate a SSB suppressed carrier signal. I suspect the pre-emphasis in the phase modulation circuit would have to be defeated, or does a phase modulation scheme automatically generate the pre-emphasis? 73 - Jim W5ZIT --- On Wed, 11/11/09, DCFluX wrote: From: DCFluX Subject: Re: [Repeater-Builder] acssb - how does it work and is it possible for the hobbyist to scratch build To: Repeater-Builder@yahoogroups.com Date: Wednesday, November 11, 2009, 9:02 PM I was playing with the ideas of making adapters, but it is supprisingly difficult to throw audio exactly 90 degrees out of phase over a broad frequency range.
