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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Tue Sep 23, 2008 6:29 am Post subject:
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It might be patchable with a S&H and Ken Stone's ASR. I'll give it a try... _________________ http://www.casia.org/modular/ |
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Tue Sep 23, 2008 7:42 am Post subject:
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I was thinking about something along these lines a couple of weeks ago. I thought about calling it "Sample and Klee".
Double the number of LF398s and you would be in some very new territory. _________________ My Site |
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loss1234
Joined: Jul 24, 2007 Posts: 1536 Location: nyc
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
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Posted: Tue Sep 23, 2008 8:25 am Post subject:
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Scott Stites wrote: | I was thinking about something along these lines a couple of weeks ago. I thought about calling it "Sample and Klee".
Double the number of LF398s and you would be in some very new territory. |
Let's make it 16 stages, shall we |
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
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Posted: Tue Sep 23, 2008 10:58 am Post subject:
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16 sounds good. always up for moving into new territory. _________________ You can check your anatomy all you want, and even though there may be normal variation, when it comes right down to it, this far inside the head it all looks the same. |
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loss1234
Joined: Jul 24, 2007 Posts: 1536 Location: nyc
Audio files: 41
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Scott Stites
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Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Tue Sep 23, 2008 12:11 pm Post subject:
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The simplest schematic using an LF398 is Rene Schmitz's YASH, IMO. It's got quite a bit of droop, but you can increase the size of the sample cap and sample width cap to decrease that.
It's really a nice little circuit - complete with clock, S&H, and external clock input using very few parts.
http://www.uni-bonn.de/~uzs159/
Click on "S&H" to the left, then click on "YASH" (Yet Another Sample and Hold). _________________ My Site |
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Scott Stites
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Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Tue Sep 23, 2008 12:16 pm Post subject:
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You can also put a SPST switch across the pulse cap (470 pF), and it becomes a Track and Hold when you close the switch. _________________ My Site |
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
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Posted: Tue Sep 23, 2008 3:00 pm Post subject:
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Scott Stites wrote: | You can also put a SPST switch across the pulse cap (470 pF), and it becomes a Track and Hold when you close the switch. |
i'm a little shaky on the basics... are you talking about using a switch to bypass the 470 pF cap?
thanks
d _________________ You can check your anatomy all you want, and even though there may be normal variation, when it comes right down to it, this far inside the head it all looks the same. |
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Sine
Joined: Sep 10, 2007 Posts: 111 Location: Netherlands
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Posted: Tue Sep 23, 2008 4:07 pm Post subject:
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Ooh, tricky ... even more if you want to daisy-chain them
precision becomes a huge factor because you will be adding an amount of error with each step. |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Tue Sep 23, 2008 4:50 pm Post subject:
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loss1234 wrote: | can someone recommend/post a SIMPLE schematic for a sample and hold, either using an lf398 or an opamp, so that i could try and make 4, 6 or 8...or more as a big module to try out this idea?
thanks |
this is Kunii921's, about as minimal as it gets
http://masa921.hp.infoseek.co.jp/image/kairo/sh.gif |
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
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fluxmonkey
Joined: Jun 24, 2005 Posts: 708 Location: cleve
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Posted: Tue Sep 23, 2008 6:07 pm Post subject:
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bubblechamber wrote: | is this from the future? |
no, from japan (which is similar)... _________________ www.fluxmonkey.com |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Tue Sep 23, 2008 6:09 pm Post subject:
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Sadly no, it is Japanese style YYMMDD |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Tue Sep 23, 2008 6:17 pm Post subject:
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andrewF wrote: | Sadly no, it is Japanese style YYMMDD |
Almost ISO notation, good! _________________ Jan
also .. could someone please turn down the thermostat a bit.
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urbanscallywag
Joined: Nov 30, 2007 Posts: 317 Location: sometimes
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Posted: Tue Sep 23, 2008 6:52 pm Post subject:
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I'm a big fan of ISO style dates. Every day just gives an "increment" of the date number. |
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Tue Sep 23, 2008 9:54 pm Post subject:
Re: S&H sequence generator |
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andrewF wrote: | Anyone with 4 or 5 S&H modules and a mixer care to patch this up and report back? |
OK, I just tried it with seven stages. It gives interesting patterns, but it's hard to predict and control. Probably not my favorite method of pattern generation. I used my TGTSH generators and found that the patern could also be varied by clocking off a TRI wave and varying the different threshold levels.
But I agree with Dan, a bank of S/H modules is definitely worth having.
Ian |
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Peake
Joined: Jun 29, 2007 Posts: 1113 Location: Loss Angeles
Audio files: 3
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Posted: Tue Sep 23, 2008 10:03 pm Post subject:
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Ah, Japanese design- that explains the initial WTF transistors are those! effect
Are there any ICs out there which house multiple S/H cells? Individual I/O or single I/multiple O? Isn't there an SSM or Curtis IC for that? It would be good for this application. _________________ We are selling emotions, there are no emotions in a grid. -mwagener
"IC 741. Sometimes you don't want fidelity." -Small Bear Electronics Catalog |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
Audio files: 1
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Posted: Wed Sep 24, 2008 2:07 am Post subject:
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Well -- you can often use Analog Switch ICs for creating S&Hs - these are easy enough to find in quad versions and not too $$$
Analog Devices do a few..
AD684 - but $$$ and only +/-5v supply...
There's also the SMP0x range but these look to have internal sample caps and some are multiplexed (not what you'd want for this?) _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Wed Sep 24, 2008 6:06 am Post subject:
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Quote: | i'm a little shaky on the basics... are you talking about using a switch to bypass the 470 pF cap? |
Yep. The LF398 will pass any signal as long as the clock input is high (if it's configured to do so, which it is on the YASH). The cap creates a very thin, 3 uS pulse, so the LF398 passes the signal for 3 uS, then shuts off the input and holds the sample on the cap. By bypassing that cap, instead of a fast pulse, you get a high for as long as the clock is high. So while the clock is high, the output of the LF398 tracks the input, and when the clock goes low, the LF398 freezes the sample at that point. Very cool effect, esp if you're using an LFO as the input.
Take care,
Scott _________________ My Site |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Wed Sep 24, 2008 7:53 am Post subject:
Re: S&H sequence generator |
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frijitz wrote: |
OK, I just tried it with seven stages. It gives interesting patterns, but it's hard to predict and control. Probably not my favorite method of pattern generation. I used my TGTSH generators and found that the patern could also be varied by clocking off a TRI wave and varying the different threshold levels.
But I agree with Dan, a bank of S/H modules is definitely worth having.
Ian |
cheers
it sounds a good option would be a bank of S&H modules on one panel with all the in/outs and trigger inputs pre-patched and an inverting/non inverting scaling mixer for the feedback paths, like the one on the top of the CGS VCO . it may be easier to control with negative feedback |
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andrewF
Joined: Dec 29, 2006 Posts: 1176 Location: australia
Audio files: 4
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Posted: Thu Nov 20, 2008 4:26 am Post subject:
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well I'm 16 hours away from some beer and 3 months summer holidays
and one of my plans is to develop a circuit based on a series of S&H sub-modules.
It seems to me a cmos 4066 or two would do the job of 4 or 8 FETs.
Is there any reason not to use 4066 for switching the S&H? FETs seem a lot more popular in these ccts...why?
cheers |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
Audio files: 1
G2 patch files: 1
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Posted: Thu Nov 20, 2008 6:09 am Post subject:
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I'd say use something along the lines of the DG211 (there's many variants - and be aware that some are active high while others are active low - that's shot me before)
Pretty much the same as 4066, but good with bipolar signals. Probably makes your ideas a whole load easier! _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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Tim Servo
Joined: Jul 16, 2006 Posts: 924 Location: Silicon Valley
Audio files: 11
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Posted: Sat Nov 22, 2008 9:02 pm Post subject:
S&H sequence generator |
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Hi All,
So I'm a tad confused on the concept. I haven't actually tried this, but if you had several S/Hs connected in series and triggered by the same pulse, wouldn't they all "capture" the same voltage level? I mean, while the sample pulse is high, the circuit simply passes the input to the output. If this happens on several circuits in series, aren't you essentially connecting all of them end to end?
I would think that you would actually need to pulse the last S/H first, and then pulse the upstream units in turn. Now, you could do this with a single pulse driving several integrators / comparators (each int/comp would have a slightly different time constant so that the S/H units were triggered sequentially). Another (MUCH simpler) way of implementing a cascaded S/H array is the method Ken Stone and others use, where you trigger each S/H in turn, and merely switch the outputs using an analog multiplexer:
http://www.cgs.synth.net/modules/cgs34_asr.html
Anyway, I've gotten a bit off track here, but my basic question is, does the S/H configuration shown in the first post actually work, or do all the outputs go to the same level?
I await wisdom from those who have actually hooked this up and looked at the various S/H outputs.
Tim (watch, I'll be out when the UPS guy delivers the wisdom) Servo |
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