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Author Topic: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )  (Read 41100 times)

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #60 on: October 26, 2009, 05:55:49 PM »
@Sparks,

Opto isolation sounds like a good idea if I can get something fast enough. I will build this pure sin box with no protection but I will only use it to drive another box or board that then will have the finals in it, fast schmitt and FETs for squares (with a little PWM) and some beefier amp stage for sin. This box will have some isolation in it and also it power input line will have non inductive shunt for scoping total drive power. For COP calculation I will ignore the draw of the sin gennies and micro and just look at the final drive stages draw.

@GK

I will be taking all the clocks off the 3 modules and making a small daughter card with one clock and 3 same length coax runs to feed each module. One clock module should handle the fanout and be able to drive 3 DDS chips OK.

The DDS chips are 5bit programmable for phase (thru the serial bus), so 32 sector resolution. i.e. I can set each oscillators phase to these degrees:

0 ... 11.25 ... 22.5 ... etc. all the way up to 348.75 and back to 0

So I should be able to set up a reasonable 3 phase signal at 0, 123.75 & 236.25 degrees at any frequency, might be interesting to try and get stuff spinning in the double digit MHz range, coil placements could perhaps be moved slightly to compensate for the imperfect 3phase angles.

2 phase (for quadrature) will be spot on at 0 and 90 degrees.
« Last Edit: October 26, 2009, 09:56:03 PM by Yucca »

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #61 on: October 26, 2009, 07:41:41 PM »
Just ordered one of these:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=390098652853

Now I have the case dimensions I will start to plan and lay out the vero boards. It will be a tight squeeze so I'll wait for the case to arrive before I commit to soldering anything.

After thought I want to firewall the case with RF shield and have the oscillators on one side and the micro on the other. All digital and power lines will pass through feedthrough caps on the firewall.

Each RF module will also have its own shield to minimise crosstalk, these shields will be made from stiff carboard and wide aluminium tape. RG174 coax will be used to bring the final signals to the front panel.


giantkiller

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #62 on: October 27, 2009, 05:41:40 AM »
@Yucca,
And that will equate to a full metal jacket8)

innovation_station

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #63 on: October 27, 2009, 12:37:00 PM »
great work yucca ...

you have yourself a verry nice control unit ...

i was lucky enough to get many cases for for building tpu controllers inside of...  they are solid alum forged ... they were originally designed for rf applacations ...

i will soon gut a unit and start building

but i want a tube unit ...  8)

aswell i have aquired a few more tube amps ...  ;D

agin great work yucca ...

ist!

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #64 on: October 27, 2009, 12:43:14 PM »
great work yucca ...

you have yourself a verry nice control unit ...

i was lucky enough to get many cases for for building tpu controllers inside of...  they are solid alum forged ... they were originally designed for rf applacations ...

i will soon gut a unit and start building

but i want a tube unit ...  8)

aswell i have aquired a few more tube amps ...  ;D

agin great work yucca ...

ist!

Cheers ist, forged alu cases are real nice and dont come cheap, you're sitting on a few dollars just for the ALU scrap price there!

Tube controller, sounds like a very interesting build. be sure to hook us up with more info as it progresses.

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #65 on: October 29, 2009, 07:37:01 PM »
I think I'll call it TRIFORCE.

I'll probably print this out, cover it with selotape and then stick it to the box.

p.s. yes I have adventured in the land of Hyrule many times lol.

Quote
Once the goddesses had completed their tasks, they departed for the heavens, and left behind three golden triangles. In these, they put their power to govern all things; this relic became known as the Triforce.

innovation_station

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #66 on: October 30, 2009, 03:13:52 AM »
love it yucca ... 

what do you think the cost of a complete osc unit would be ..

im verry intrested in unit .. 

but i ideally want a 4 freq unit with percise control right up to 1 ghz ...

for my matter manipulation device but do i really need something like that ......

ist!

great logo

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #67 on: October 30, 2009, 11:37:37 AM »
love it yucca ... 

what do you think the cost of a complete osc unit would be ..

im verry intrested in unit .. 

but i ideally want a 4 freq unit with percise control right up to 1 ghz ...

for my matter manipulation device but do i really need something like that ......

ist!

great logo

Hi ist,

You need one DDS module for each channel:

Quote
$29.50  for the DDS-60 Kit (without AD9851 DDS chip)
$21.00  for the AD9851 DDS chip
$80.00  for the Assembled & Tested DDS-60, including the AD9851 DDS chip

So if you can get free chip samples from Analog Devices then each module can be had for $29.50

Then you need something to program the chips frequency with, you can use a PC or you can use a standalone microcontroller like Im using. The whole micro ready built with screen and chip in socket costs $50 delivered to canada.

So depending on which route you go for the DDS module you could build one for as low as $140 all up.

Jog wheel is optional, the micro board already has buttons to control the thing with. Also you need to find case, wires and sockets etc, but you probably have that stuff already.

As youre a long standing member I could email you the software to program your micro board with. Just plug into a PC USB port and upload it with one mouse click.

I don´t know about going up to 4 channel  GHz with variable frequency and phase, that´d be a serious bit of kit :o

innovation_station

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #68 on: October 30, 2009, 01:26:13 PM »
thank you yucca!

for your responce..

the reason im intrested in upto 1ghz is because i have 2 skids of thease and they are stable to 1 ghz and i think they are quite a few watt rf amps ...

here is a picture

ist!

btw in my limited teck knowalage .. i beleave thease rf amps or TRUNK AMPS... amp both ways send and return ...

as i have said i have not played them yet or hardly even looked at em  i know a few teckies that know thease things well  so when it comes time ..  i will ask advice


Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #69 on: October 30, 2009, 03:23:45 PM »
thank you yucca!

for your responce..

the reason im intrested in upto 1ghz is because i have 2 skids of thease and they are stable to 1 ghz and i think they are quite a few watt rf amps ...

here is a picture

ist!

btw in my limited teck knowalage .. i beleave thease rf amps or TRUNK AMPS... amp both ways send and return ...

as i have said i have not played them yet or hardly even looked at em  i know a few teckies that know thease things well  so when it comes time ..  i will ask advice

Hi Ist, After googling a bit it seems Trunk amps are either one way or two way. They are high spec kit with bandwidths typically from like 5MHz to approaching 1GHz.

In the higher frequencies you will lose signal unless everything is tricked out with coax runs that are carefully impedance matched.

I've found that above say 10MHz you have to be real careful with wiring capacitance and inductance, every piece of wire becomes an LC component.

A pure sine wave is the easiest thing to keep intact, but if you want to propogate pulses then its a real art to keep that pulse together and not have it collapse into a load of unphased sin harmonics.

P.S.
I've got through a few parts of the youtube vid about the guy who teleported to mars, it's fantastic listening! Thanks for the heads up.

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #70 on: November 06, 2009, 08:43:09 PM »
Just finished writing a double buffered graphics API in C++ for the NOKIA 3310 LCD screen:

http://www.youtube.com/watch?v=dHV8wELuOa8

I am moving to this screen instead of the NOKIA 6610 screen because:

its cheaper.
it seems easier on the eye than the 6610 screen.
it will make case layout and installation easier because the screen board has 4 nice mounting holes on it.

stprue

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #71 on: November 07, 2009, 05:03:40 PM »


@Yucca

Awesome!

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #72 on: November 08, 2009, 01:40:50 PM »
Cheers stprue,

I've finished the main freq screen and also decided on the layout for the main menu.

FREQU TUNING:
Gives the main frequency screen where user is able to adjust any decade of any channel.

PHASE TUNING:
Gives the phase screen where user is able to adjust phase of any channel.

LIN SWEEPING:
User is able to set start and end points of a linear sweep and also specify the number of milliseconds that the sweep should take. The unit will output a trigger signal from a fourth BNC connector so a scope can be hooked up and used as a frequency response monitor for the coil under test.

LOG SWEEPING:
As above only the sweep is logarithmic, sweep step is proportional to frequency.

HARMONIC LOC:
User can set multiplication factors for f2 and f3. For example if f2 is set to 2.000 and f3 is set to 3.000 we will get the first and second harmonic. When harmonic lock is active the main freq screen will show a small padlock in bottom right. Then if the user sets say f1 to 1MHz then f2 and f3 will automaticly go to 2MHz and 3MHz. Of corse any multiplication factors can be entered.

At the moment it will be 1D sweeping, In the future I will expand to 3D sweeping by putting a second level into the sweep menus and maybe combining LIN and LOG into one item to give me another menu position (any ideas for another menu function are welcome)
« Last Edit: November 08, 2009, 02:35:28 PM by Yucca »

Yucca

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #73 on: November 08, 2009, 01:41:39 PM »
.

innovation_station

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Re: Homebrew 3 Channel Pure SIN Generator ( 0 ... 60MHz )
« Reply #74 on: November 08, 2009, 03:39:17 PM »
 ;D

BRO   I LOVE IT!

YOUR ROCK AT WHAT YOU DO SIR!   

IST STANDS BACK IN AWE .... 

YOU MAKE THAT WORK BRO ...  I HAVE ABOUT HUMMMMM   1000 USES FOR SUCH A UNIT ...  ;)

I JUST CANT BUILD SOMETHING LIKE THAT ...  SO ILL BUY SOME FROM YOU IN THE FUTURE ..  8)

PEACE IST!