Nyquist Aliaser Project

Started by Eb7+9, January 14, 2006, 10:26:04 AM

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syndromet

I think I'm gonna try this one. Sounds right up my alley!
Some really nooby questions:
Would it possible to build this by the layout in the beginning of this tread, using perfboard and cutting the lines in the midle?
What does the colours in the layout mean?
Where do I add ground and +9?
Would a lm072 / LM082 be OK?
Can I change the transistors to more common types?

I totaly understand if you don't care to answer this.  ;)
My diy-site: www.syndromet.com

Eb7+9

#61
Quote from: syndromet on April 04, 2006, 01:15:41 PM
Would it possible to build this by the layout in the beginning of this tread, using perfboard and cutting the lines in the midle?
What does the colours in the layout mean?
Where do I add ground and +9?

(edit ...) duh, I get it now ... yep cut right through the middle and you'll get what they call IC stripboard which is what I use ... sorry for the confusion - in my stripboard layout red simplistically stands for either +9 (sgnl rail) or+8 (clk rail) and green stands for either gnd (sgnl gnd) or +1 (clk gnd) ... orange is VCO bias ... of course you'll have to figure out how to separate the clock and signal rails for yourself ...  I left this open for experimentation - and as I said, they can be reversed depending on the filtering approach ...

Quote
Would a lm072 / LM082 be OK?
Can I change the transistors to more common types?

I use 2n5484's because it's the only good low-turn-on nchan jFET I can buy off the street up here ... the op-amp that I used in my circuit is a TL072 - spec sheet says it limits the output swing to about 1.5v at both rails under light load but scope said something more like 1.0v with the ones I tried in this circuit and in my latest optical S/H that uses the same clock ...

it's important to use low turn-on devices and medium to high-swing op-amps because the 9volt space is split between three important factors : (i) sufficient gain and headroom for signal to pass in the first gain stage, (ii) the DC on the first drain sets the average voltage in the sampler which has to lie betwen two limits or else sampling won't take place in part of the signal headroom range that lies around said DC and (iii) the clock circuit has to provide enough output swing, again, for the sampler to turn on and off properly ...

If you find alternative device combos that work please post - this will help others who want to try this stuff out ...

jc

sta63bmx

I laughed my ass off at the guitar sound clips.  You know what it sounds EXACTLY like?  EXCITEBIKE!

Doot doot deet doo doot deeeeeeeee
Doot doot DEET doo doot deeeeeeeee
brinka dinka doo dee dee doo doo doo doo
DOO doot doot doot duh deet!

dunnnn dunnnnn dunnnnnn
DEEDLY dunnnnnn
Dunt deeeee DUN
dunnnnnnnnnn NUNT

doot
doot
doot

BWEEEEEEEEEEEEEEEEE!

*farting motorcycle sounds*

Some really cool sounds, yes, but the Excitebike sound had me laughing out loud.  Really neat!

bwanasonic

Quote from: sta63bmx on April 05, 2006, 11:39:54 PM
I laughed my ass off at the guitar sound clips.  You know what it sounds EXACTLY like?  EXCITEBIKE!

I was reminded of one my favorite Nintendo video game scores - Earthbound.

I need a slightly more idiot friendly version of this project, as I am unfamiliar with the grounding concepts needed.

Kerry M