On Sat, 22 Dec 2012 15:34:34 -0800, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>On Sat, 22 Dec 2012 15:04:03 -0800, Jon Kirwan <jonk@infinitefactors.org> wrote:
>
>>On Wed, 19 Dec 2012 07:11:45 -0800 (PST), George Herold
>><gherold@teachspin.com> wrote:
>>
>>>On Dec 18, 9:45&#4294967295;pm, Jon Kirwan <j...@infinitefactors.org> wrote:
>>>> <snip>
>>>> I agree that it could sell for the cost of a scope --
>>>> depending on what is included. For example, it may provide
>>>> alternate functions (signal generator?) which later have
>>>> practical use, as well. And especially with a nice manual.
>>>
>>>Well that's fine too... If you want to grow it into something
>>>bigger.
>>>We also have a use for function generators that go below a few Hz.
>>>We resell these protek function generators, which leave a bit of a bad
>>>taste in my mouth.  There is a six or seven digit frequency display,
>>>the last few digits of which are meaningless, you change the freq.
>>>from 1.00000 kHz to 1.00001 kHz on the display, but nothing changes at
>>>the output.
>>><snip>
>>
>>Take a look at this:
>>
>>	http://www.ebay.com/itm/130815250956
>>
>>The idea adds value. If it included an input for a 10MHz
>>reference, too...
>
>Digital scopes don't need timebase checking, and DC is good enough for checking
>the vertical.

I think George wasn't thinking of excluding training on
analog scopes. Whether or not a replacement design chooses to
consider them is another matter, of course. But since a new
design is still in the research stage, everything is on the
table so to speak, I think.

>>Anyway, still throwing ideas together and thinking.
>>
>>Jon
>
>I think I met that swap-meet scope guy. I wanted to buy a scope and he said it
>worked. I offered him a check with the understanding that I'd stop payment if it
>didn't work. He refused.
>
>Another swap-meet trick. If somebody says "I don't know if it works", then it
>doesn't.
>
>But ebay has mostly killed the electronic flea markets. Most ebay stuff *does*
>work.

In case others might wonder what you are referring to and
haven't read the ebay link, the ebay seller (Reed Dickinson)
writes this about his experience with swap meets:

      I recently attended the bi-monthly electronics swap
      meet in Santa Ana, CA. There was an out-of-state
      vendor there who had a number of Tektronix 475A and
      485 oscilloscopes that were very reasonably priced.
      The vendor assured me that all of these oscilloscopes
      were in working order; however, there was no power
      available to verify this statement. I accepted this
      explanation and after several minutes of intense
      haggling we arrived at a mutually agreeable price
      and then I was the proud owner of four 485 and three
      475A Tektronix oscilloscopes. During the next week I
      fired them up and found that only two of the 475A's
      and none of the 485's had a trace visible on them.
      One of the 485's was lacking the inverter board and
      as well had no tunnel diodes nor any of the socketed
      ICs. Needless to say, I was not a happy shopper. And
      to top it all off, I did not get the seller's contact
      information. I decided that I needed a portable
      calibration tester and a very long extension cord.
      I do not design extension cords but I do design
      portable testers; the Pyramid Generator is the
      culmination of that effort.

Jon

On Sat, 22 Dec 2012 15:04:03 -0800, Jon Kirwan <jonk@infinitefactors.org> wrote:

>On Wed, 19 Dec 2012 07:11:45 -0800 (PST), George Herold
><gherold@teachspin.com> wrote:
>
>>On Dec 18, 9:45&#4294967295;pm, Jon Kirwan <j...@infinitefactors.org> wrote:
>>> <snip>
>>> I agree that it could sell for the cost of a scope --
>>> depending on what is included. For example, it may provide
>>> alternate functions (signal generator?) which later have
>>> practical use, as well. And especially with a nice manual.
>>
>>Well that's fine too... If you want to grow it into something
>>bigger.
>>We also have a use for function generators that go below a few Hz.
>>We resell these protek function generators, which leave a bit of a bad
>>taste in my mouth.  There is a six or seven digit frequency display,
>>the last few digits of which are meaningless, you change the freq.
>>from 1.00000 kHz to 1.00001 kHz on the display, but nothing changes at
>>the output.
>><snip>
>
>Take a look at this:
>
>	http://www.ebay.com/itm/130815250956
>
>The idea adds value. If it included an input for a 10MHz
>reference, too...

Digital scopes don't need timebase checking, and DC is good enough for checking
the vertical.

>
>Anyway, still throwing ideas together and thinking.
>
>Jon

I think I met that swap-meet scope guy. I wanted to buy a scope and he said it
worked. I offered him a check with the understanding that I'd stop payment if it
didn't work. He refused.

Another swap-meet trick. If somebody says "I don't know if it works", then it
doesn't.

But ebay has mostly killed the electronic flea markets. Most ebay stuff *does*
work.


-- 

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

On Wed, 19 Dec 2012 07:11:45 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

>On Dec 18, 9:45&#4294967295;pm, Jon Kirwan <j...@infinitefactors.org> wrote:
>> <snip>
>> I agree that it could sell for the cost of a scope --
>> depending on what is included. For example, it may provide
>> alternate functions (signal generator?) which later have
>> practical use, as well. And especially with a nice manual.
>
>Well that's fine too... If you want to grow it into something
>bigger.
>We also have a use for function generators that go below a few Hz.
>We resell these protek function generators, which leave a bit of a bad
>taste in my mouth.  There is a six or seven digit frequency display,
>the last few digits of which are meaningless, you change the freq.
>from 1.00000 kHz to 1.00001 kHz on the display, but nothing changes at
>the output.
><snip>

Take a look at this:

	http://www.ebay.com/itm/130815250956

The idea adds value. If it included an input for a 10MHz
reference, too...

Anyway, still throwing ideas together and thinking.

Jon

On Dec 19, 3:59=A0pm, John Larkin <jlar...@highlandtechnology.com>
wrote:
> On Wed, 19 Dec 2012 07:11:45 -0800 (PST), George Herold
>
>
>
>
>
> <gher...@teachspin.com> wrote:
> >On Dec 18, 9:45 pm, Jon Kirwan <j...@infinitefactors.org> wrote:
> >> On Tue, 18 Dec 2012 18:26:06 -0800, josephkk
>
> >> <joseph_barr...@sbcglobal.net> wrote:
> >> >On Tue, 18 Dec 2012 17:06:51 -0800 (PST), George Herold
> >> ><gher...@teachspin.com> wrote:
>
> >> >>> >Hmmmm. I think i have some beautiful ways to make autoset very
> >> >>> >challenging, a few modulated signals with the modulation signal a=
ppearing
> >> >>> >elsewhere. And we can produce many more signals easily so long as=
 they do
> >> >>> >not have to be really high quality of their type. Maybe 30 to 50 =
signals?
> >> >>> >Indeed, low quality signals may be more challenging.
>
> >> >>> >+/- 12 and 15 V stuff is getting scarce, maybe we want to change =
to +/- 5
> >> >>> >V analog and 3.3 V logic. As you say packaging and PS are major c=
ost
> >> >>> >items, let's see what we can do about that.
>
> >> >>> >?-)
>
> >> >>> If you do move forward on this, I'd appreciate being kept in
> >> >>> the loop at some level acceptable to you. I'm very interested
> >> >>> if that's okay.
>
> >> >>Yeah sure... Jon as I've said to you, I don't expect to make much (i=
f
> >> >>any) money from teachscope.. the volume/cost is too low unless someo=
ne
> >> >>wants to market it to groups other than physics labs.
> >> >>I saw the 50MHz Rigol scope, for $330?,
> >> >>can't sell teachscope for more than a scope!
>
> >> >I am not so sure about that, a lot depends on how we position ourselv=
es in
> >> >the market. Just the same it would be a tough sell.
>
> >> I agree that it could sell for the cost of a scope --
> >> depending on what is included. For example, it may provide
> >> alternate functions (signal generator?) which later have
> >> practical use, as well. And especially with a nice manual.
>
> >Well that's fine too... If you want to grow it into something
> >bigger.
> >We also have a use for function generators that go below a few Hz.
> >We resell these protek function generators, which leave a bit of a bad
> >taste in my mouth. =A0There is a six or seven digit frequency display,
> >the last few digits of which are meaningless, you change the freq.
> >from 1.00000 kHz to 1.00001 kHz on the display, but nothing changes at
> >the output.
>
> Sounds like they might use a binary DDS and do ugly rounding to
> decimal. That problem can be worked around, but the DDS clock
> frequency gets messy, or you need a huge, like 64 bit, phase
> accumulator.

I didn't look at it that close, but it seemed to tick over on what
might have been binary numbers.  So I can forgive maybe one 'funny'
digit, but this had three!  You'd never know as a user, unless you had
something to compare it with.

In other ways the protek is OK, I've used the sweep function and burst
mode,
(I think I was even able to send an external trigger for the burst.)
And like I said the only cheap DDS I know that has milli Hertz
resolution.

George H.
>
>
>
>
>
>
>
> >> >>Maybe it could be a sparkfun thing?
>
> >> >That is worth serious consideration, it could be sold case less and n=
o PS,
> >> >with designs for the case and labeling. Normal PS might be a USB wall
> >> >wart (~ 3$ US ?) and make the rest onboard, with their test signals a=
s
> >> >part of the signals to look for.
>
> >> I think making it "ready to go" out of the box will give it
> >> wider utility. It would be nice to give it the look and feel
> >> of a typical Rigol instrument, in fact.
>
> >> But I'm also for anything fun.
>
> >> Perhaps start by examining existing oscilloscope tutorials
> >> (some manuals have been produced for that) and similar
> >> manuals for similar tutoring devices like this. See what
> >> others have considered and done. Make a list, work through it
> >> and organize it with an eye to functional blocks. Then widdle
> >> away expensive functional blocks that can't be justified
> >> (along with the associated features that require them.) Then
> >> see where that leaves things and find the right balance.
> >> (Delving enough into certain details may be required to lock
> >> down that they can be achieved, of course.)
>
> >Grin, =A0knock yourself out! =A0In some ways I fear that (many)
> >physicist's have already abandoned 'scopes. =A0 I was at a summer
> >meeting and saw demo experiments where the interface was National
> >Instruments (DAC)-> labview-> computer. =A0 With no real time display
> >of the signal. =A0It seemed crazy to me not to have a scope to give (at
> >least) real time diagnostics of what was happening. =A0But clearly a
> >scope was not a tool that they felt comfortable using... sigh.
>
> I toured the Cornell EE dept when The Brat was at Cornell. I counted
> about 40 computer screens and one oscilloscope screen.

Maybe they keep the 'scope guys in the back room, their lab benches
will be messier.. clutter looks bad to visiting parents.

George H.
>
> --
>
> John Larkin =A0 =A0 =A0 =A0 Highland Technology, Inc
>
> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com
>
> Precision electronic instrumentation
> Picosecond-resolution Digital Delay and Pulse generators
> Custom laser drivers and controllers
> Photonics and fiberoptic TTL data links
> VME thermocouple, LVDT, synchro =A0 acquisition and simulation- Hide quot=
ed text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

On Wed, 12 Dec 2012 17:49:40 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

>On Dec 12, 7:03&#4294967295;pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
>Web-Site.com> wrote:
>> On Wed, 12 Dec 2012 15:14:48 -0800 (PST), George Herold
>>
>>
>>
>>
>>
>> <gher...@teachspin.com> wrote:
>> >On Dec 12, 5:51 pm, John Larkin <jlar...@highlandtechnology.com>
>> >wrote:
>> >> I'm being asked to make some replacement FSK modems for a system I
>> >> designed about 30 years ago... not much money to be made, really just
>> >> a charity job. I originally used the XR2206 as the transmit
>> >> oscillator, and they are gone. Well, Mouser has one piece for $83.
>>
>> >> MAX038 is gone, too. Jameco has some 2206 DIPs, which I could scoop
>> >> up, I guess.
>>
>> >Do you need a lot? &#4294967295;We've got several tubes left over from a
>> >discontinued
>> >gizmo*.
>>
>> >> Anybody know of a classic analog sinewave generator chip? A uP and DDS
>> >> would be a lot of hassle. And I'd like to be able to set the
>> >> mark/space frequencies with pots.
>>
>> >> I guess I could make a triangle oscillator and sort of bend it into a
>> >> sine wave. THD wouldn't matter much.
>>
>> >You could use a clocked 4017 with different R's into a opamp summing
>> >junction. &#4294967295;(Phil or James suggested it a while back.) &#4294967295;With ten steps
>> >you move most of the 'distortion' out to the 9th and 11th harmonic.
>>
>> >George H.
>>
>> >*Teachscope, sold for a few hundred and put out 12 different 'signals'
>> >that the students would have to 'go find' with a 'scope. &#4294967295;I wish
>> >someone would make the current day equivalent out of a uC.
>>
>> >> The receive direction is easy. I'll use my almost-famous dual tach
>> >> circuit
>>
>> >>https://dl.dropbox.com/u/53724080/Circuits/DoubleTach.jpg
>>
>> >> with a decent output filter and a comparator.
>>
>> >> --
>>
>> >> John Larkin Highland Technology, Inc
>>
>> >> jlarkin at highlandtechnology dot comhttp://www.highlandtechnology.com
>>
>> [snip non-compliant sig]
>>
>> You can easily make a modem from active filter structures. &#4294967295;That's
>> what I used for the OmniComp/GenRad international-frequency-selectable
>> modem circa 1981-82... dirt cheap but very accurate.
>>
>> The discriminator was patented...
>>
>> &#4294967295; &#4294967295; &#4294967295;http://www.analog-innovations.com/SED/Pat-4472816.pdf
>
>Neat, what was the mixer?   (an XOR?)
>
>George H.
>>

I previously misunderstood your question... see Fig 5 in the patent...
it's a synchronous "phase flipper" ;-)
		
                                        ...Jim Thompson
-- 
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

On Dec 19, 3:13=A0pm, Spehro Pefhany <speffS...@interlogDOTyou.knowwhat>
wrote:
> On Wed, 19 Dec 2012 07:11:45 -0800 (PST), George Herold
>
>
>
>
>
> <gher...@teachspin.com> wrote:
> >On Dec 18, 9:45 pm, Jon Kirwan <j...@infinitefactors.org> wrote:
> >> On Tue, 18 Dec 2012 18:26:06 -0800, josephkk
>
> >> <joseph_barr...@sbcglobal.net> wrote:
> >> >On Tue, 18 Dec 2012 17:06:51 -0800 (PST), George Herold
> >> ><gher...@teachspin.com> wrote:
>
> >> >>> >Hmmmm. I think i have some beautiful ways to make autoset very
> >> >>> >challenging, a few modulated signals with the modulation signal a=
ppearing
> >> >>> >elsewhere. And we can produce many more signals easily so long as=
 they do
> >> >>> >not have to be really high quality of their type. Maybe 30 to 50 =
signals?
> >> >>> >Indeed, low quality signals may be more challenging.
>
> >> >>> >+/- 12 and 15 V stuff is getting scarce, maybe we want to change =
to +/- 5
> >> >>> >V analog and 3.3 V logic. As you say packaging and PS are major c=
ost
> >> >>> >items, let's see what we can do about that.
>
> >> >>> >?-)
>
> >> >>> If you do move forward on this, I'd appreciate being kept in
> >> >>> the loop at some level acceptable to you. I'm very interested
> >> >>> if that's okay.
>
> >> >>Yeah sure... Jon as I've said to you, I don't expect to make much (i=
f
> >> >>any) money from teachscope.. the volume/cost is too low unless someo=
ne
> >> >>wants to market it to groups other than physics labs.
> >> >>I saw the 50MHz Rigol scope, for $330?,
> >> >>can't sell teachscope for more than a scope!
>
> >> >I am not so sure about that, a lot depends on how we position ourselv=
es in
> >> >the market. Just the same it would be a tough sell.
>
> >> I agree that it could sell for the cost of a scope --
> >> depending on what is included. For example, it may provide
> >> alternate functions (signal generator?) which later have
> >> practical use, as well. And especially with a nice manual.
>
> >Well that's fine too... If you want to grow it into something
> >bigger.
> >We also have a use for function generators that go below a few Hz.
> >We resell these protek function generators, which leave a bit of a bad
> >taste in my mouth. =A0There is a six or seven digit frequency display,
> >the last few digits of which are meaningless, you change the freq.
> >from 1.00000 kHz to 1.00001 kHz on the display, but nothing changes at
> >the output.
>
> >> >>Maybe it could be a sparkfun thing?
>
> >> >That is worth serious consideration, it could be sold case less and n=
o PS,
> >> >with designs for the case and labeling. Normal PS might be a USB wall
> >> >wart (~ 3$ US ?) and make the rest onboard, with their test signals a=
s
> >> >part of the signals to look for.
>
> >> I think making it "ready to go" out of the box will give it
> >> wider utility. It would be nice to give it the look and feel
> >> of a typical Rigol instrument, in fact.
>
> >> But I'm also for anything fun.
>
> >> Perhaps start by examining existing oscilloscope tutorials
> >> (some manuals have been produced for that) and similar
> >> manuals for similar tutoring devices like this. See what
> >> others have considered and done. Make a list, work through it
> >> and organize it with an eye to functional blocks. Then widdle
> >> away expensive functional blocks that can't be justified
> >> (along with the associated features that require them.) Then
> >> see where that leaves things and find the right balance.
> >> (Delving enough into certain details may be required to lock
> >> down that they can be achieved, of course.)
>
> >Grin, =A0knock yourself out! =A0In some ways I fear that (many)
> >physicist's have already abandoned 'scopes. =A0 I was at a summer
> >meeting and saw demo experiments where the interface was National
> >Instruments (DAC)-> labview-> computer. =A0 With no real time display
> >of the signal. =A0It seemed crazy to me not to have a scope to give (at
> >least) real time diagnostics of what was happening. =A0But clearly a
> >scope was not a tool that they felt comfortable using... sigh.
>
> They can get a real-time display from a suitable .vi, but typically
> the lab guys have it set up to autoscale so it's very hard to get a
> analog-y feel for what's going on, despite the rolling chart
> display. For example, a signal that is trending will look like it
> has much less noise than a signal that is stable with exactly the
> same noise level.

It was worse than that.  There was a prof, who had made a different
mechanism for doing the bouncing gold wires, quantum conductance
mesasurment.  (The bouncing wires give transient steps in the
resistance of 12.7(?)k ohms(e^2/h,) (Really thin wires work best.)
Instead of bouncing wires, he had the wire on a beam, that he flexed
from the back with a fine pitched screw.  I thought it might work, but
the dam# labview program, could only capture the time record and then
display it later. So he'd move it around and then go see what he
'caught'... no better than bouncing wires.  I so wanted to push the
prof out of the way, grab a scope, and see if the mechanism worked.
I'll have to build my own someday.

George H.
>
>
>
> >George H.
>
> >> Jon- Hide quoted text -
>
> >> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

On Wed, 19 Dec 2012 07:11:45 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

>On Dec 18, 9:45&#4294967295;pm, Jon Kirwan <j...@infinitefactors.org> wrote:
>> On Tue, 18 Dec 2012 18:26:06 -0800, josephkk
>>
>>
>>
>>
>>
>> <joseph_barr...@sbcglobal.net> wrote:
>> >On Tue, 18 Dec 2012 17:06:51 -0800 (PST), George Herold
>> ><gher...@teachspin.com> wrote:
>>
>> >>> >Hmmmm. &#4294967295;I think i have some beautiful ways to make autoset very
>> >>> >challenging, a few modulated signals with the modulation signal appearing
>> >>> >elsewhere. &#4294967295;And we can produce many more signals easily so long as they do
>> >>> >not have to be really high quality of their type. &#4294967295;Maybe 30 to 50 signals?
>> >>> >Indeed, low quality signals may be more challenging.
>>
>> >>> >+/- 12 and 15 V stuff is getting scarce, maybe we want to change to +/- 5
>> >>> >V analog and 3.3 V logic. &#4294967295;As you say packaging and PS are major cost
>> >>> >items, let's see what we can do about that.
>>
>> >>> >?-)
>>
>> >>> If you do move forward on this, I'd appreciate being kept in
>> >>> the loop at some level acceptable to you. I'm very interested
>> >>> if that's okay.
>>
>> >>Yeah sure... Jon as I've said to you, I don't expect to make much (if
>> >>any) money from teachscope.. the volume/cost is too low unless someone
>> >>wants to market it to groups other than physics labs.
>> >>I saw the 50MHz Rigol scope, for $330?,
>> >>can't sell teachscope for more than a scope!
>>
>> >I am not so sure about that, a lot depends on how we position ourselves in
>> >the market. &#4294967295;Just the same it would be a tough sell.
>>
>> I agree that it could sell for the cost of a scope --
>> depending on what is included. For example, it may provide
>> alternate functions (signal generator?) which later have
>> practical use, as well. And especially with a nice manual.
>
>Well that's fine too... If you want to grow it into something
>bigger.
>We also have a use for function generators that go below a few Hz.
>We resell these protek function generators, which leave a bit of a bad
>taste in my mouth.  There is a six or seven digit frequency display,
>the last few digits of which are meaningless, you change the freq.
>from 1.00000 kHz to 1.00001 kHz on the display, but nothing changes at
>the output.

Sounds like they might use a binary DDS and do ugly rounding to
decimal. That problem can be worked around, but the DDS clock
frequency gets messy, or you need a huge, like 64 bit, phase
accumulator.


>>
>> >>Maybe it could be a sparkfun thing?
>>
>> >That is worth serious consideration, it could be sold case less and no PS,
>> >with designs for the case and labeling. &#4294967295;Normal PS might be a USB wall
>> >wart (~ 3$ US ?) and make the rest onboard, with their test signals as
>> >part of the signals to look for.
>>
>> I think making it "ready to go" out of the box will give it
>> wider utility. It would be nice to give it the look and feel
>> of a typical Rigol instrument, in fact.
>>
>> But I'm also for anything fun.
>>
>> Perhaps start by examining existing oscilloscope tutorials
>> (some manuals have been produced for that) and similar
>> manuals for similar tutoring devices like this. See what
>> others have considered and done. Make a list, work through it
>> and organize it with an eye to functional blocks. Then widdle
>> away expensive functional blocks that can't be justified
>> (along with the associated features that require them.) Then
>> see where that leaves things and find the right balance.
>> (Delving enough into certain details may be required to lock
>> down that they can be achieved, of course.)
>
>Grin,  knock yourself out!  In some ways I fear that (many)
>physicist's have already abandoned 'scopes.   I was at a summer
>meeting and saw demo experiments where the interface was National
>Instruments (DAC)-> labview-> computer.   With no &#4294967295;real time&#4294967295; display
>of the signal.  It seemed crazy to me not to have a &#4294967295;scope to give (at
>least) real time diagnostics of what was happening.  But clearly a
>scope was not a tool that they felt comfortable using... sigh.
>

I toured the Cornell EE dept when The Brat was at Cornell. I counted
about 40 computer screens and one oscilloscope screen.


-- 

John Larkin         Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation