Thanks John,
What amount do you consider expensive?
$12K is expensive.
That is indeed beautiful. Although, to be honest, I never really had anOn Tue, 29 Sep 2009 15:27:53 -0700, Joerg <invalid@invalid.invalid
wrote:
John Larkin wrote:
On Tue, 29 Sep 2009 12:53:36 -0700, Joerg <invalid@invalid.invalid
wrote:
John Larkin wrote:
On Tue, 29 Sep 2009 13:34:14 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
John Larkin wrote:
On Tue, 29 Sep 2009 09:25:15 -0700, Joerg <invalid@invalid.invalid
wrote:
John Larkin wrote:
On Mon, 28 Sep 2009 17:43:22 -0700, Joerg <invalid@invalid.invalid
wrote:
John Larkin wrote:
On Mon, 28 Sep 2009 20:05:23 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
John Fields wrote:
On Mon, 28 Sep 2009 10:25:05 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
On Sat, 26 Sep 2009 17:58:27 -0700, Archimedes' Lever
OneBigLever@InfiniteSeries.Org> wrote:
On Sat, 26 Sep 2009 16:52:40 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
On Sat, 26 Sep 2009 17:28:50 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
John Larkin wrote:
There's the slideback technique: drive a comparator with RF on one
side, DC feedback on the other. Tease the DC appropriately.
I once made a slideback sampling oscilloscope, using tunnel diodes, as
my EE senior project. I won an award and had to attend a dreadful IEEE
chapter banquet and repeat it to a bunch of old-fart power engineers
who didn't understand a word I said. I described the slideback
sampling scope in this ng some years back and a certain party loved
the idea so much he later decided that he'd invented it himself.
http://store.americanmicrosemiconductor.com/diodes-tunnel-diodes.html
TDs are insanely expensive nowadays, ballpark $100. I used to get them
for a couple bucks from Allied. The fabrication process is insane, and
nobody ever modernized it.
There are some more modern planar germanium back diodes, essentially
low Ip tunnel diodes, but they're RF detectors, useless for switching.
Pity, I used to like tunnel diodes.
http://aeroflex.com/AMS/Metelics/pdfiles/MBD_Series_Planar_Back_Tunnel_Diodes.pdf
John
Try PiN diodes then.
For what? Certainly not switching, amplifying, oscillating, detection,
or mixing.
---
Re. switching, From:
http://en.wikipedia.org/wiki/PIN_diode
"Under zero or reverse bias, a PIN diode has a low capacitance. The low
capacitance will not pass much of an RF signal. Under a forward bias of
1 mA, a typical PIN diode will have an RF resistance of about 1 ohm,
making it a good RF conductor. Consequently, the PIN diode makes a good
RF switch."
---
Good, but not fast. PIN diodes specialize in having a lot of stored
charge, so that the signal current can be quite a bit larger than the DC
current without causing excessive distortion.
Cheers
Phil Hobbs
PINs stop behaving like PINs at low frequencies, too. So they don't
make useful wideband switches.
Got to watch the carrier lifetime. The lower the bottom of your spectrum
and the higher the RF current, the longer its carrier lifetime must be.
I found PIN diodes to be great and most of all cheap variable
attenuators as well as switched. Designed in tons of them.
But I meant active switching when I was referring to a TD. A TD would
*generate* a fast step from an arbitrarily slow drive.
I've drooled over SRDs all my life and every time I wanted to buy one I
either couldn't have one or it was outlandishly expensive. Guess
avalanching is the only game in town and if you want avalanche-rated
then a bone-simple BJT can easily shoot up to twenty bucks.
SRDs aren't hard to get. MA/Com has distributor parts, under a buck.
M-Pulse and Metelics are good about samples. If you want a few, send
me a SASE.
Oh, here it is...
229-1769 DIO SRD 30V SOT23 150PS MA44769 1PF
MA44769-287 PENSTOCK
Price 58 cents in small quantities.
They also have MA44767-287, 600 ps risetime, a little easier to drive
because it stores more charge.
These make nice edge generators and frequency multipliers. I have a
rubidium clock that generates the 6.3846826128 GHz frequency from a 10
MHz rock with an absurdly small number of cheap parts.
Thanks, John! That's a decent price. And thanks for the SASE offer, but
maybe I'll combine that with a beer at Zeitgeist when I get down there
Well, drop in. We have a zillion exotic parts in stock. And the
quality of Z's burgers has improved radically lately. Only biker bar I
know of with Chimay on tap.
As a kid I grew up in Europe and back then such exotic parts were very
hard to find over there, even at hamfests.
We were lucky. Tons of exotic surplus gear, lots of old teevees,
Allied and Lafayette and Fair Radio Sales mail-order available to
anyone, local distributors for over-the-counter transistors and
10-turn pots and such... the counter guys gave me more parts than I
ever paid for. I made a deal with my parents to dump my allowance in
favor of a revolving credit account with Allied, so I could just order
stuff. I made spending money fixing radios and TVs.
John
Still not as good as now. I just bought an excellent-condition HP 8568B
spectrum analyzer for $900. About 2 cents on the dollar. So far this
year I've bought test equipment that would have cost way over $100000
new, for probably $4k altogether. Amazing.
Cheers
Phil Hobbs
And I'm looking at, theoretically, a quarter million dollars worth of
sampling heads over there on my shelf. This is an amazing time to
start a niche business, or even an exotic hobby.
Is there anything available at reasonable cost that does zippy sampling
without needing a Goliath of a scope attached to it?
Not really. The 5000 and 7000 series scopes had sampling plugins - I
have a bunch, and they're dirt cheap now - but they were pretty bad
compared to the superb 11801-series stuff.
There is an 11802 on Ebay right now for $1k but untested, "powers up".
Thing is, I haven't gotten much more space here. A sampler for the 7704
over here would be nice. What is so bad with S-4 and 7S11? Ok, the
25psec risetime doesn't quite rival your gear but for most stuff that
should do.
That stuff works, but it's not as quantitative as the later gear. And
TDR is a fabulous thing to have, and the TDR on the 7-series stuff is
really mediocre.
Isn't this beautiful?
ftp://jjlarkin.lmi.net/Z250A.jpg
ftp://jjlarkin.lmi.net/Z250_TDR.jpg
(TDR of the test trace, J28 to J29)
There probably isn't much of a TDR market. But I believe there would be
Yes. I the US one can buy a fairly decent passenger car for that kind of
Trace impedances matter a lot to us. Board houses sometimes take
One market for a small, affordable USB TDR would be to sell to board
Ok, I understand that. But since you know the geometries from the
Those theories sure are weird
That is next to impossible to do without TDR.
But it sure is beautiful there:
Expensive indeed. Any idea what makes these buggers so expensive?
The usual. High NRE costs, low sales volume, combined with the desire to
Total C would be a very crude way to guess trace impedances. Too
Yup, very nice. It was occupied by the Nazis during the war, and thereIt's also cool to add SMAs to access power pour layers and TDR them.
That blows away all sorts of cockeyed theories about bypassing
high-speed stuff.
Those theories sure are weird
Transitions, like pcb-to-connector, are also interesting to TDR. Leads
to x-acto slashing sometimes.
That is next to impossible to do without TDR.
There are some little USB samplers, but they're very expensive.
Probably not much of a market anymore and the TDR guys in the field
dont' need a precision under a foot to figure where they have to drop
the bucket of their Kubota.
Too much cheap surplus stuff on ebay, too. I'd love to do a cheapish
USB TDR, but there's probably no good market.
There probably isn't much of a TDR market. But I believe there would be
a market for a sampling scope app where people can check (repetitive)
timings to within several picoseconds. With comm data rates almost in
the two-digit GHz-range that market should be growing.
One market for a small, affordable USB TDR would be to sell to board
houses. The Polar Instruments stuff (from the Channel Islands, another
story) is expensive and very dated.
But it sure is beautiful there:
http://lisamm.files.wordpress.com/2009/08/guernsey.jpg
Tek used to assemble scopes there, for tax reasons. After that stopped
We, at least, use metal:
And I bet you have a TVS across the 12VDC line. I'd rather that folks
After the radial-lead polyfuse. The surface-mount ones suck.
Luckily few of my cusomers want to mess with LabView.
Good man
What are they using? SCADA software?
The jet engine and FADEC test folks usually write their own systemJohn Larkin wrote:
On Wed, 30 Sep 2009 12:59:03 -0700, Joerg <invalid@invalid.invalid
wrote:
John Larkin wrote:
On Wed, 30 Sep 2009 11:30:28 -0700, Joerg <invalid@invalid.invalid
wrote:
Nico Coesel wrote:
John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
On Wed, 30 Sep 2009 16:29:03 GMT, nico@puntnl.niks (Nico Coesel)
wrote:
John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 29 Sep 2009 12:53:36 -0700, Joerg <invalid@invalid.invalid
wrote:
There are some little USB samplers, but they're very expensive.
What amount do you consider expensive?
$12K is expensive.
Expensive indeed. Any idea what makes these buggers so expensive?
The usual. High NRE costs, low sales volume, combined with the desire to
make a living.
You wouldn't believe what I've seen in some electro-optical gear. A
couple of <$1 photodiodes, some MMICs or RF amps in the same price
range, a couple BNC connectors, a (chintzy and cheap) PVC plastic
enclosure, price tags between $500 and $1000. For that money they didn't
even include a TVS to guard against the common ESD or "whoops, got the
power reversed" accidents in a lab. That would have pushed the cost by
at least 50c ...
We, at least, use metal:
http://www.highlandtechnology.com/DSS/J740DS.html
And I bet you have a TVS across the 12VDC line.
After the radial-lead polyfuse. The surface-mount ones suck.
Good man
The usual scenario would be that either the power supply limits or a PVC
stench develops.
I'd rather that folks
would buy from companies like yours. But often they gravitate towards
those that they know from the past or that have a "name" in their field.
The gear is sometimes fancy but very pathetic. A sad episode was a TEC
plus laser diode driver combo box, very expensive. Janitor plugged in
his big industrial Hoover, turned it on, all the LEDs on the box lit up
and then ... *PHUT*
It's similar in other fields. I've lost count how many times fairly
simple test jobs were done with very expensive NI gear and LabView while
we did it for around a hundred bucks with a LabJack at a client. It is
often impossible to convince folks that this much less expensive route
can yield the same results.
Luckily few of my cusomers want to mess with LabView.
What are they using? SCADA software?
Wow, ok, that's a different caliber. One of my newer clients in in thatOn Wed, 30 Sep 2009 14:26:46 -0700, Joerg <invalid@invalid.invalid
wrote:
John Larkin wrote:
On Wed, 30 Sep 2009 12:59:03 -0700, Joerg <invalid@invalid.invalid
wrote:
John Larkin wrote:
On Wed, 30 Sep 2009 11:30:28 -0700, Joerg <invalid@invalid.invalid
wrote:
Nico Coesel wrote:
John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
On Wed, 30 Sep 2009 16:29:03 GMT, nico@puntnl.niks (Nico Coesel)
wrote:
John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 29 Sep 2009 12:53:36 -0700, Joerg <invalid@invalid.invalid
wrote:
There are some little USB samplers, but they're very expensive.
What amount do you consider expensive?
$12K is expensive.
Expensive indeed. Any idea what makes these buggers so expensive?
The usual. High NRE costs, low sales volume, combined with the desire to
make a living.
You wouldn't believe what I've seen in some electro-optical gear. A
couple of <$1 photodiodes, some MMICs or RF amps in the same price
range, a couple BNC connectors, a (chintzy and cheap) PVC plastic
enclosure, price tags between $500 and $1000. For that money they didn't
even include a TVS to guard against the common ESD or "whoops, got the
power reversed" accidents in a lab. That would have pushed the cost by
at least 50c ...
We, at least, use metal:
http://www.highlandtechnology.com/DSS/J740DS.html
And I bet you have a TVS across the 12VDC line.
After the radial-lead polyfuse. The surface-mount ones suck.
Good man
The usual scenario would be that either the power supply limits or a PVC
stench develops.
I'd rather that folks
would buy from companies like yours. But often they gravitate towards
those that they know from the past or that have a "name" in their field.
The gear is sometimes fancy but very pathetic. A sad episode was a TEC
plus laser diode driver combo box, very expensive. Janitor plugged in
his big industrial Hoover, turned it on, all the LEDs on the box lit up
and then ... *PHUT*
It's similar in other fields. I've lost count how many times fairly
simple test jobs were done with very expensive NI gear and LabView while
we did it for around a hundred bucks with a LabJack at a client. It is
often impossible to convince folks that this much less expensive route
can yield the same results.
Luckily few of my cusomers want to mess with LabView.
What are they using? SCADA software?
The jet engine and FADEC test folks usually write their own system
software, using RT Linux or some such. Test runs are often script
driven, may involve thousands of channels of stimulation and
acquisition, and may run for days. They have to simulate 1553 busses,
pitot tubes, thermocouples, tach pickups, vibration things, pressure
sensors, LVDTs, all sorts of nonsense. And then faults on all of the
above.
I just got DAQFactory back to work. Was like pulling teeth. Almost like
Now, think of something snappy like that to say about Iran.
On Sep 28, 3:22 am, "Speeders & Drunk Drivers are MURDERERS"
xeton2...@yahoo.com> wrote:
"John Fields" <jfie...@austininstruments.com> wrote in messagenews:6opvb5l27upk1u2ut4qpokhr586j3dlmdh@4ax.com...
On Sat, 26 Sep 2009 17:48:21 -0700, Archimedes' Lever
OneBigLe...@InfiniteSeries.Org> wrote:
On Sat, 26 Sep 2009 15:51:08 -0700, "Speeders & Drunk Drivers are
MURDERERS" <xeton2...@yahoo.com> wrote:
BULLSHIT! My MOSFET's went even farther than this shit, yup mine are in sub NanoOhm. No heat, they blow my 36V 150watts light bulbs twice, no heat on the MOSFET, no death affect like your MOSFETs under constant current. A thumb size TO-220 can produce 1.2kw of switching power.
NXP claims world's first sub 1 milliOhm MOSFET in a Power S08 ...
Jul 8, 2009 ... NXP Semiconductors has unveiled the world's first n-channel sub 1 milliOhm 25 V MOSFET, PSMN1R2-25YL, and is claiming the lowest ever RDSon ...
YOUR MOSFETs (no apostrophe, idiot)?
What company do YOU make or design MOSFETs for?
Otherwise, it is you that is full of shit.
---
Indeed.
Just thinking about what he's proposing against what can actually be
done with ohmic material leads to the conclusion that he is, indeed,
full of shit.
Here are the proofs of why you jerks are real stupid:
1) You believe in something that you shouldn't be believing such as the hype of the new Chevy Volt 200 MPG, Even a light hybrid Honda/Toyota hybrid can't make it above 50mpg especially under your fat asses, you got to do some trick to go above 50mpg. Now a new heavy weight called Volt claiming to hit 200mpg, that's the real shit there.
2) What happens to your hype to send men to Mars in 2004 by your fucking BUSH? See, the whole thing is dead like I said back then.
3) I have tangible truth about everything I said here, it's your own problem for lacking education. You have nothing but bogus formulas, stupid beliefs in bogus things such as WMD in Iraq, Rosy economy, then the whole thing collapse. That's why I never care to give you respect. You judgments are so dirt low as usual. I would be stupid if I reveal anything new to you in technologies..
NOW FLUSH ALL OF YOU LOW-LIFE AMERICAN JERKS!!
Captain: What in the hell happened?
Mechanic: Somebody set up us the bomb.
Engineer: An unknown assailant has planted an explosive device!
Operator: We get signal.
Communication operator: Captain! We have received a transmission!
Captain: What ! Captain: What?!
CATS: All your base are belong to us. CATS: With the help of the
Federation Government forces, CATS has taken all of your bases.
CATS: You are on the way to destruction. CATS: Your ship is about to
meet its doom as well.
Captain: What you say !! Captain: IIt can't be...!
CATS: You have no chance to survive make your time. CATS: Cherish
these few remaining seconds of your lives.
Captain: For great justice. Captain: Our hopes for our future ...