It is all software. The DSB suppressed carrier, fully complex signal is made just like any other DSB signal would be. This is added coherently to the carrier. Since you are not modulating the envelope of the carrier, but adding two coherent signals, this allows the supermodulation AM you have discovered. You are the first I KNOW ABOUT to have expressed all of this so clearly. The "200%" modulation stuff in your videos is something I have not thought about since I never dreamed anyone would go that high.
Congrats. Bob N4HY On Mon, Feb 14, 2011 at 1:57 PM, W1AEX - Rob <[email protected]> wrote: > Setup: Flex 5000A, Power SDR 2.0.16, Win XP/SP2 > > I use my Flex 5000A now and then on AM when I don’t feel the urge to fire > up my big plate modulated rigs. Naturally, I was curious how the Flex looks > on my scope in the AM mode. I was pleasantly surprised at how the Flex could > handle the asymmetry in my voice and produce very healthy looking positive > peaks without nearing the baseline. Performance on the test bench was > equally impressive. The Flex 5000A passes triangle waves cleanly from 10 cps > to over 5000 cps in the AM mode. My plate modulated rigs can’t do that! The > biggest surprise came when I ran a 1000 cps sine wave through the Flex. It > cleanly reaches 125% in the positive direction before it reaches the > baseline. Normally, an AM transmitter will reach 100% positive and 100% > negative simultaneously when fed a sine wave. Broadcast stations use > expensive processing equipment to limit negative peaks to achieve asymmetry > like this. I’m not aware of any Inovonics processing equipment inside my > Flex 5000A, so this has me wondering how the asymmetry was achieved. Note > that the Power SDR compander and EQ were not active during the triangle wave > and sine wave measurements. > > 1. Is this asymmetry common in all Flex 5000A’s or is mine extra special? > 2. Is this a result of hardware or software? > 3. Is this a symptom of possible I/Q imbalance? > > Don’t get me wrong, I like the concept of asymmetry in the AM mode (as long > as it’s heading in the positive direction) and I don’t view this as a > problem. I’m just curious how it was achieved. > > 73, > > Rob W1AEX > > Picture sine wave test: > http://members.cox.net/w1aex.fn31/flexsine.jpg > Picture triangle wave test: > http://members.cox.net/w1aex.fn31/flextri.jpg > Video sine wave test: http://www.youtube.com/watch?v=1gNsWl8BBD0 > Video triangle wave test: http://www.youtube.com/watch?v=UpoCipk-U08 > > -- > One thing I'm certain of is that there is too much certainty in the world. > > > _______________________________________________ > Flexedge mailing list > [email protected] > http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz > This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used > for posting topics related to SDR software development and experimentalist > who are using beta versions of the software. > _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
