I get great audio reports on AM with my SDR-1000. Does that mean I will get results similar to Rob's?
Edwin Marzan AB2VW > Date: Mon, 14 Feb 2011 14:07:28 -0600 > From: [email protected] > To: [email protected] > CC: [email protected] > Subject: Re: [FlexEdge] Flex 5000A – PSDR 2.X.X and Amplitude Modulation > Surprise > > 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. _______________________________________________ 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.
