Totem-Pole Progress Report

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Totem-Pole Progress Report

Postby ke1gf » Mon Jul 12, 2004 4:03 pm

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Here is version 1 of the totem pole driver. I'm driving 2 x 3 single-ended push-pull rf deck good for about 300 watts carrier. As you can see in the picture I'm using a TTL clock module as the frequency source.

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This is version 2 of the board. This one accepts a 1.5 volt into 50 ohm sine wave as the frequency source.

All the missing chips are basically the same wiring/layout as version 1 so there shouldn't be any problem dropping the chips in!

I am going to make a heatsink to fit over the row of chips at the top.

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Here you can see that in a few days I could drive my Class-E rig with a MF259B antenna analyzer! but I'm not gonna! look below. This board doesn't take much power, only a few miliwatts of drive!

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This is the output of the sine to TTL converter. the %DC is adjustable from independantly for each module from 1/3% to 2/3% on.

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Here is the next hurdle, the microprocessor controlled DDSynth.

When everything is said and done I upload all of my documentation to my www addr at wpi and hopefully I should have a working demo for boxboro.

Or should I hold the documentation for a QEX article?
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Postby blaine » Mon Jul 12, 2004 4:20 pm

Thats very Kool Bill :lol:

nice work
Blaine N1GTU
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so I installed Linux." --- LinuxNewbie.org
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Postby ke1gf » Mon Jul 12, 2004 4:36 pm

blaine wrote:Thats very Kool Bill :lol:


hehehe 8)
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Postby frank carcia » Mon Jul 12, 2004 7:55 pm

Bill,
What DDS do you plan to use? Consider using a 74AC74 in the output to get both phases. It will also reduce spurs because the only time there is any effect is at the change of logic state. This is a very cool project since most rice boxes have poor synthesizers. Good Luck! fc
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Postby frank carcia » Mon Jul 12, 2004 7:57 pm

Bill,
What DDS do you plan to use? Consider using a 74AC74 in the output to get both phases. It will also reduce spurs because the only time there is any effect is at the change of logic state. This is a very cool project since most rice boxes have poor synthesizers. Good Luck! fc
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Postby ke1gf » Mon Jul 12, 2004 8:07 pm

frank carcia wrote:Bill,
What DDS do you plan to use? Consider using a 74AC74 in the output to get both phases. It will also reduce spurs because the only time there is any effect is at the change of logic state. This is a very cool project since most rice boxes have poor synthesizers. Good Luck! fc


Frank I'm using the AD9851 synth...

I thought of using a Flip-Flop, but I chose a 74S86 instead.

Peace
-Bill 'GF
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Excellent Adventure.

Postby N9NEO » Mon Jul 12, 2004 8:16 pm

Smokin good on the dds work. Hope you can knock the price down from commercial price. I was wondering if you were going to have a meaningful summer experience. Will also look very good on a resume ya know! I'm sure there's a bunch of people looking for an easydriver for Class E. Rice is for eatin, not drivin class E or ridin down the road on.

Good luck.

Bob
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Postby ke1gf » Mon Jul 12, 2004 8:49 pm

we'll see Bob, bit pricey now. But it may be possible to get the whole thing down to $75 or less. But that's more of a pipe dream than reality.
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Postby frank carcia » Tue Jul 13, 2004 7:14 am

Bill,
AC logic has a stronger output than S. It is also faster. The AC logic has a totem pole so logic high produces more current 25 or 50 ma source and sink. fc
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Postby ke1gf » Tue Jul 13, 2004 12:27 pm

That AC logic looks sexy frank... I'll keep it in mind for my next parts order.

It's also pretty cheap. cheaper than 74S, why?

Thanks,
-Bill 'GF
Last edited by ke1gf on Tue Jul 13, 2004 12:40 pm, edited 1 time in total.
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Postby frank carcia » Tue Jul 13, 2004 12:29 pm

Bill,
Nobody uses S logic any more power hog and old. fc
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Postby ke1gf » Tue Jul 13, 2004 12:49 pm

Looks good frank, I'll probably need the AC(T) logic when I build one to drive my 20 pill rig.

Thanks
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Postby ke1gf » Wed Jul 14, 2004 1:20 am

Hi, I made more progress today. I finally built the main DDS board and gave it a test drving my totem-pole board.

I think I need to tweak the transformer/resistor network a bit to get the triggering the way I want it, but it was a productive day to say the least.

Image

Image

Here's a little movie that I made, the %DC control isn't exactly what I wanted but a tweak of the input transformer/resistors should fix that.

http://users.wpi.edu/~smithw/Sync_TP_Driver/DSCN0228.MP4

Best
-Bill 'GF
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Postby frank carcia » Wed Jul 14, 2004 7:08 am

Very Cool Bill.
Gee I bought some displays like that a Hostradres a while ago.
Made sure your clock has low phase noise. I can't do MP4 here at work
so is there another way to open the file? fc
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Postby ke1gf » Wed Jul 14, 2004 12:49 pm

frank carcia wrote:Very Cool Bill.
I can't do MP4 here at work
so is there another way to open the file?


Frank, use I use quicktime to view the file.
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