Single Sideband Suppressed Carrier (SSBSC) Video Demonstration

[richard.vanderveen]

My guess is the x300 series won't get an SSB upgrade...

 

[rorban]

Bob,

Any chance the 8300 gets the SSB mode?

The only Orban processors capable of running SSB are the 5500, 5518 (which is a stand-alone stereo generator). and 8600. (Of course, the 8500 can run SSB after being upgraded to an 8600 with the available upgrade kit.)

The other Orban FM processors don't have enough spare DSP power to implement the SSB generator. The 5518 will get the upgrade fairly soon.

Bob Orban

 

[oldiesstation]

Very interesting article in July 4 Radio World on SSBSC.Believers and non-believers. Smart move on Mr. Orban to incorporate this in the mid-level priced 5500. Have the feeling alot of demo's will be going out.The benefit of SSBSC without paying a high end price.Brillant...

 

[satech]

Wheatstone is touting the "Automatic Multipath Controller" in their Vorsis processors as an alternative to SSBSC:

http://wheatstone-blog.com/?p=1350

Their description of how it works sounds a lot like some processing tricks that were used as far back as the '80s, such as stereo enhancement with width limiting which restricts L-R to no more than 70% of L+R. That way, the separation of "wide stereo" mixes is reduced (thus improving mono loudness and reducing multipath) while the stereo imaging of more modern recordings is preserved or even improved.

 

[PaulyBoy]

Wheatstone is touting the "Automatic Multipath Controller" in their Vorsis processors as an alternative to SSBSC:

http://wheatstone-blog.com/?p=1350

Their description of how it works sounds a lot like some processing tricks that were used as far back as the '80s, such as stereo enhancement with width limiting which restricts L-R to no more than 70% of L+R. That way, the separation of "wide stereo" mixes is reduced (thus improving mono loudness and reducing multipath) while the stereo imaging of more modern recordings is preserved or even improved.

I tried this concept out a number of years ago, and it did not make much difference with regards to multipath.

 

[oldiesstation]

Same can be said with those experimenting with SSB as well.Seemed it helped with multipath in some locations and not others.The jury is still out on this.Multipath is a strange animal..

 

[chriscollins]

Bob,

Any chance the 8300 gets the SSB mode?

The only Orban processors capable of running SSB are the 5500, 5518 (which is a stand-alone stereo generator). and 8600. (Of course, the 8500 can run SSB after being upgraded to an 8600 with the available upgrade kit.)

The other Orban FM processors don't have enough spare DSP power to implement the SSB generator. The 5518 will get the upgrade fairly soon.

Bob Orban

I put that update on my 5500... I am curious as to why the 8300 can't do it. Doesn't the 8300 have a more powerful DSP than the 5500?

 

[bigtom101]

I tried this concept out a number of years ago, and it did not make much difference with regards to multipath.

Out of curiosity, what equipment and radios did you use to test out the system?

 

[fm-engineer]

Bob,

Any chance the 8300 gets the SSB mode?

The only Orban processors capable of running SSB are the 5500, 5518 (which is a stand-alone stereo generator). and 8600. (Of course, the 8500 can run SSB after being upgraded to an 8600 with the available upgrade kit.)

The other Orban FM processors don't have enough spare DSP power to implement the SSB generator. The 5518 will get the upgrade fairly soon.

Bob Orban

I put that update on my 5500... I am curious as to why the 8300 can't do it. Doesn't the 8300 have a more powerful DSP than the 5500?

I’m pretty sure the 8300 has been discontinued. I believe the 5500 has replaced the 2300, 5300, and 8300.

 

[rorban]

I’m pretty sure the 8300 has been discontinued. I believe the 5500 has replaced the 2300, 5300, and 8300.

Correct. The current Orban FM processors are the 5500, 8500, and 8600, plus the 5518 stereo encoder (which only has overshoot limiting).

 

[Jeff_Keith]

Same can be said with those experimenting with SSB as well.Seemed it helped with multipath in some locations and not others.The jury is still out on this.Multipath is a strange animal..

I too hope that SSBSC will be a useful tool for reducing multipath, which is why we put an SSB mode into our Wheatstone processors
for use during SSBSC's experimental stage. But in the meantime, we are also pursuing other methods for reducing multipath that don't require permission from the FCC and also work with every receiver. I am not sure how previous lab tests were conducted, but in field tests we
conducted and for a large number of stations in real-world multipath conditions the ability to automatically modify the L+R/L-R ratio according
to program material and competitive conditions has made a huge improvement in perceived multipath on existing DSBSC receivers. The technique is compatible with every stereo receiver and is something stations can use today without special permission from the FCC. You can find the history behind the algorithm in an article about it here: http://wheatstone-blog.com/?p=1350 .

I am interested in your opinions.

 

[Navion]

That I know of, there are only a few stereo generators with this capability. The Omnia 11 and 9 and the Optimod 5500 and 8600. I'm sure a lot of the others will follow as I think the methods are pretty well documented and it doesn't seem to challenging to implement in DSP. The Stereotool folks are working on it too. I made a request to Nautel to include SSB in their VS exciters. They say they're looking at it but who knows.

 

[satech]

Would reducing one sideband of the MPX signal, instead of suppressing it entirely, improve compatibility with some of the problematic receivers (notably the Sony HD Radio tuner) while still preserving the claimed advantages of SSBSC?

 

[rrsounds]

Would reducing one sideband of the MPX signal, instead of suppressing it entirely, improve compatibility with some of the problematic receivers (notably the Sony HD Radio tuner) while still preserving the claimed advantages of SSBSC?

I'm not an expert on this, but from what I have read I believe that removing the upper sideband also requires a corresponding increase in the level of the lower sideband by 6dB. Not sure how you would deal with this gain situation if the upper sideband were only partially reduced.

Kind Regards,
David

 

[WNTIRadio]

The LSB would have to be increased by the amount that the USB has been lowered by. But by adding a full, even if "quieter" USB, the advantages of SSB are mostly erased.

Going to be testing in on one of my client stations in MA soon. Just need to get the composite STL replaced.

 

[hvz]

Another option that I want to look at at some point is what happens if you change the DSB/SSB split. The implementation in the Omnia 9 and 11 (I don't know about Orban) uses DSB for frequencies below approx. 150 Hz and then goes to SSB.

Based on my (very limited) understanding of what exactly happens in a receiver when multipath issues are present, I think that SSB will mainly have benefits for very high frequencies.

Take for example a broadcast of a very uninteresting program with only single sinusoids in anti-phase.

If you have a 15 kHz tone in anti-phase, DSB gives you 2 spikes, at 38-15=23 kHz and 38+15=53 kHz. SSB gives you 1 spike, at 23 kHz, with twice the power. The difference between 23 and 53 kHz is huge, so it makes sense that SSB wins.

But if you take a 2 kHz tone, the situation might be very different. DSB again gives you 2 spikes, at 36 and 40 kHz. SSB gives 1 spike at 36 kHz, which is twice as loud. In this case, 36 and 40 kHz are pretty close together, and a twice as loud 36 kHz tone might very well be worse - or at least not much better - than having two different tones.

A special case might be 12666 Hz. Here 2 tones at frequencies 25.333 and 2 * 25.333 = 50.666 Hz are replaced by a single, twice as loud tone at 25.333 Hz. I'm really guessing here, but this frequency might be a tipping point above which SSB has a clear gain. I'm not too sure about this though, because much depends on how a radio reacts on multipath distortion (is a twice as high or twice as loud tone twice as bad?).


If there is no clear benefit of SSB at lower frequencies, radios like this Sony tuner might behave better if the SSB/DSB separation slope is changed, with no or very limited impact on reception on other receivers.