SmartSDR and CESSB

Mike va3mw

SmartSDR is the only software that actually has CESSB built in.  What that means is that you get about the equivalent of an extra 2.51db output on SSB.  

That is almost like getting 200 PEP out of your 100 watt radio.  

CESSB is some amazing math that can be read about in this QEX article.  
http://www.arrl.org/files/file/QEX_Next_Issue/2014/Nov-Dec_2014/Hershberger_QEX_11_14.pdf


I thought I would re-share this story for all the new Flex owners.

Mike va3mw

Donovan van Loggerenberg

Does not help CW ops... HAHAHA

Mike va3mw

I think that is why they call it CESSB and not CECW.  LOL

Paul Christensen, W9AC

For some time now, HPSDR's PSDR mRx operating software also has CESSB built in.

Paul, W9AC

Mike va3mw

Good to know.  I didn't know that PSDR had it installed, but I see they did that in version v3.2.21.  

Bill W2PKY

Its good to focus on the positive aspects of the product now and then. I use the graphic equalizer to flatten the response of my transmitted signal. It's amazing how many SSB signals **** much of their available power on bass frequencies. FLEX audio is superb.

Mike va3mw

Hi Bill

CESSB processing happens in the RF section and cannot be achieved in the audio chain, just in case you are not aware.    

Using the onboard graphics equalizer is also a good exercise.   Bob Heil does a great talk on the equalization on the spoken word as examined by Bell Labs.  I should see if I can find it.

73, Mike va3mw

Bill -VA3WTB

They did something to PSDR ,,but from what I have heard so far it sounds very un natural as they have it very loud,,like they are yelling at you all the time,,,not very nice for talking, very tireing.

K2CB Eric Dobrowansky

The issue is you have more control over the settings in OpenHPSDR. If it is set up properly, you can sound just as good, if not better, than SSDR. It is just like any other radio, the more settings you have, the more work it takes to make it sound good. On another note, my old Icom IC-781 still has more average talk power than my Flex 6500 or ANAN-100, even with CESSB enabled. Eric K2CB

Bill -VA3WTB

Then I take it none of them have got things set properly, I listen to them talk during the week and all they talk about is how loud they can be without distortion. But the sound, is yelling, they are all the same. But it is a great feature, Flex really did a wonderful job on it,,sounds very natural.

Mike va3mw

Hi Eric

That is interesting about the 781.  How do you measure your talk power?

Mike

K2CB Eric Dobrowansky

Both an oscilloscope and an average reading wattmeter. And on the air reports confirm some radios sound stronger than others for the same PEP output level. SSDR was quite anemic until CESSB became available.

Ria

I guess this is one reason why "you don't need ALC with a Flex" and it makes total sense. 

Ken Davis

For us beginners, what is CESSB ?

Tim - W4TME

Google is your friend in these cases
https://en.wikipedia.org/wiki/Controlled-envelope_single-sideband_modulation

And from the SmartSDR Software User's Guide

Processor (PROC) button: Clicking on this button will enable the W9GR Controlled Envelope Single Sideband (CESSB) DSP algorithm resulting in additional talk power.  The speech processor may be on or off and has three different settings when on.  In the NOR or normal setting, the processor provides minimal additional gain and simply prevents audio peaks from clipping or producing power in excess of the set level.  In the DX setting, some compression is provided to the audio to increase the overall sideband envelope which results in a stronger signal that may be more readily heard at a distance.  The DX+ setting adds even more compression increasing your talk power or “punch” without incurring significant audio distortion.  DX+ is most effective if you increase the low cut TX filter to between 200-400 Hz in order to concentrate your talk power in the audio frequency range that has the greatest intelligibility.  This feature is available only in SSB, AM and FM modes.

Michael Coslo

One of the disadvantages of having a Flex is you begin to hear how plain awful many other radios sound. 8^) 

Ken Davis

Tim - Thank you very much for this info.  Sometimes acronyms just puzzle me. Not sure why but I did google cessb but got nothing about radios. 
Thanks again :-)
Ken