Data Slicer

[gkovar]

Could someone help explain this schematic http://wiki.radioreference.com/index.php/Image:Circut.gif

A few questions, and I may be heading down the wrong path with this so please bear (bare?) with me.

Where am I getting +12 and -12? I assume that is coming off of the serial port. From what I've read online the TXD is +12 correct? and the DTR is -12? That seems to be backwards from what the diagram shows, right?

Do I need to split my +12 and -12 off of the serial port to run to my 1N4148?
Does anyone have a link to a breadboard version of this that might help me out?

Thanks

 

[crayon]

I have always thought that schematic was poorly drawn. It would be nice if it would go away. Try this one instead:

http://www.svn.net/mycal/digital/dataslic.gif

However, if your going to be building a data slicer, why not build one that can be used on everything?

http://wiki.radioreference.com/images/c/cd/LTRDicer1.png

 

[ka3jjz]

And what is stopping you (hint hint) ? You can replace the gif yourself - just upload it and point to it using the [[media]] command, and you're done.

Just a thought....73s Mike

 

[pro92b]

I have always thought that schematic was poorly drawn. It would be nice if it would go away. Try this one instead:

http://www.svn.net/mycal/digital/dataslic.gif

Notice that R2 = R3 in the referenced schematic. It might work with a PRO-2006 but that is too much hysteresis for most modern IF chips.

 

[gkovar]

Crayon,

Thanks!
I like both of those schematics better.
I think the reason I went with the first one was because it seemed like the most available parts at my RS. However, both of those schematics look nice.

I think step one will be to (finally) install the discriminator tap and try out unitrunker. Then I'll roll into completing my data slicer.

Thanks

 

[crayon]

And what is stopping you (hint hint) ?

I'm too lazy to do it.

 

[crayon]

Notice that R2 = R3 in the referenced schematic. It might work with a PRO-2006 but that is too much hysteresis for most modern IF chips.

What do you recommend instead?

I was going to say something about a TL082 circuit, but I didn't want you to start throwing things at me.

 

[crayon]

I think step one will be to (finally) install the discriminator tap and try out unitrunker. Then I'll roll into completing my data slicer.

FWIW .. . UniTrunker is based on the DOS Trunkers et al. It might be hard to understand what is going on without experience running the DOS version first.

That being said, still give it a go and remember to buffer your discriminator output. Sound cards can be tricky. Lastly, if/when you do run DOS Trunker, do it with a DOS OS. It will help when it comes to troubleshooting.

HTH's

 

[gkovar]

Crayon,

When you say run it with a DOS OS, are you suggesting to stick with something like win95/98 instead of win2k or are you suggesting I dig out the old DOS disks and reinstall that?

Also, where can I read more about buffering my discrim out? Is there a section in the wiki that goes more into this sort of info that I'm missing?

 

[pro92b]

What do you recommend instead?

I was going to say something about a TL082 circuit, but I didn't want you to start throwing things at me.

I'd change R2 to 1K. I wouldn't change the 741 to a TL082

 

[crayon]

Crayon,

When you say run it with a DOS OS, are you suggesting to stick with something like win95/98 instead of win2k or are you suggesting I dig out the old DOS disks and reinstall that?

aye. You can boot and run Trunker from a floppy. There are some fancy things that you can do, but that will get you going without the need to reformat anything. If you cannot find your DOS OS, surf here:

www.bootdisk.com

Also, where can I read more about buffering my discrim out? Is there a section in the wiki that goes more into this sort of info that I'm missing?

We have talked about at length the benfits of buffering your output. A simple forum search will give you lots to read. Props to you for reading the wiki, AFAIK nothing has been added in there about that. I guess it is time for me to get un-lazy and whip that into shape.

 

[gkovar]

Crayon,

My first two stops before asking a question are the wiki and a forum search. However, I skipped that step on the output buffer.
I do agree though that the wiki needs some updating on data slicers, discriminator output, etc...

Before getting interested in radios I was very much a computer nerd. So I'm sure I have enough old hardware laying around to devote a computer to running DOS.

This has been a very responsive thread. I greatly appreciate it!

 

[pro92b]

aye. You can boot and run Trunker from a floppy. There are some fancy things that you can do, but that will get you going without the need to reformat anything. If you cannot find your DOS OS, surf here:

www.bootdisk.com

A boot disk more specific to our purpose is at http://home.hvc.rr.com/bpetrow/LTR.exe. It should run on just about any PC that has a serial port, floppy drive, and 16MB of memory or more. Trunker, Etrunker, Ed, Slicer, Ltrtrunk, Ltrdump, Treport, and a program to convert AFS to decimal and hex are all available. A ramdisk is used to run everything and system files can be saved back to floppy after compressing them (roughly 2 MB uncompressed capacity). Also included is a primitive text editor and facility to make a backup copy of the floppy. Once the exe is downloaded, scan it with an antivirus program and then double click to write to floppy.

 

[gkovar]

Pro92b and crayon,

This is getting absurd I thought 2 years ago when I put my last floppy drive in my closet that I'd probably end up throwing the thing out, not putting it back into my computer to load up DOS.

On a side note and mostly a curiosity question. How many serial ports are you typically using on your computer? And are the USB to serial solutions that are available able to work with these type utilities?

Thanks again for your help.

 

[pro92b]

The computer here has one serial port. USB to serial adapters are completely useless in DOS.

 

[gkovar]

pro92b,

I'm kicking around using virtual pc. The USB setup shows up in vpc as a serial port. I was just wondering if there was any physical reason it wouldn't work assuming DOS addresses it as a "real" com port.

 

[crayon]

How many serial ports are you typically using on your computer?

I never buy a motherboard without a DB9 connector ... so, for me, all of them!



I dont know how Trunker would behave in a virtual enviroment, but I suspect not well. I am all for experimentation, so give it a try! The problem here, gkovar, is that Trunker generates a CPU interrupt for every pulse of the data train. As you can imagine it ties up the processor quite a bit, which is why it is "best" if you can run the program from DOS and even better if you can dedicate a simple computer to Trunker.

You should also know that some people say that they run Trunker in DOS Window on 2k/XP just fine. I have not tried that myself so I cannot comment on how well it will work for you or what tweaking will need to done.

 

[gkovar]

crayon,

yeah, I have a few mobos of the P3 vintage waiting for a task. However, my KVM is full...so, I'm actually thinking of booting up vpc on my powerbook and plugging in my usb-serial cable.
Not to put the cart ahead of the horse, I'll have to build my data slicer first.
In any case, will post details and results.

Thanks for all the help.

 

[crayon]

In any case, will post details and results.

Cool. I look forward to the results.

 

[nova1010]

easy data slaicer

I've never tried this one but looks real simple to make http://www.bookshock.com/articles/slicer/intro.html ceck it out.