Driver to drive?

[dcaster@krl.org]

On Wednesday, November 19, 2014 2:53:10 AM UTC-5, Ken wrote:

From what I think is the same facility;

http://ic.pics.livejournal.com/bmpd/38024980/1622553/1622553_900.jpg


Why is the ceiling fully reflective? Save on lighting?

Reflective insulation is effective for heat flow down. Not very good at keeping heat from rising.

Dan

 

[rickman]

On 11/19/2014 3:19 AM, Jamie M wrote:

On 11/18/2014 2:44 PM, sroberts6328@gmail.com wrote:
other hand goes through high power silica fibers.

Jamie, Start with Jeff Hecht's book "The Laser Guidebook" and
Silfvast's Book "Laser Fundamentals" before you go down this beam path.

The learning curve is extremely steep an


Hi,

Thanks, I recall hearing from previous discussions on here that glass
is opaque to CO2 laser wavelengths. I was also wondering about a
relatively cheap CO2 40Watt laser tube like this one:

http://www.ebay.com/itm/151058818267

Could the output laser beam from something like that be focused down
to a small enough spot that it would melt metal powder? If so I guess
as was mentioned already the bonding to the layer below might be
the reason a cheap 3D metal printer can't be made with these tubes,
otherwise it could be good for really high resolution small metal
parts. Maybe the concept of a "heated bed" common in plastic filament
3D printers could be used to keep the small (ie 1cm x 1cm) work area
hot enough to make the layers bond easier.

Your lens would need to be quartz or perhaps a plastic that is
transparent to IR. In chemistry we used quartz cuvettes to hold samples
for spectrophotometry... although I think that was for UV. I guess the
opaqueness of glass depends on the frequency of IR as we did use glass
test tubes for some IR work... I think. Heck, that was some 40+ years
ago.

--

Rick

 

On Tuesday, November 18, 2014 8:47:16 PM UTC-8, josephkk wrote:

On Mon, 17 Nov 2014 20:01:15 -0800 (PST), edward.ming.lee@gmail.com wrote:

On Monday, November 17, 2014 7:35:51 PM UTC-8, rickman wrote:
On 11/17/2014 9:15 PM, edward.ming.lee@gmail.com wrote:
On Monday, November 17, 2014 5:56:18 PM UTC-8, rickman wrote:
On 11/17/2014 8:46 PM, edward.ming.lee@gmail.com wrote:
On Monday, November 17, 2014 5:29:40 PM UTC-8, rickman wrote:
On 11/17/2014 11:53 AM, edward.ming.lee@gmail.com wrote:
On Monday, November 17, 2014 8:13:27 AM UTC-8, jurb...@gmail.com wrote:
If they actually squatted, they should not win the case. No disagreement there. Now if they stopped paying rent because the roof caved in or something...


In my case, the root leaked for one day, did not cave in. I spent thousands to repair it afterward. But he seems entitled to living free forever because it leaked one day. It never leaked again. This is just an excuse, if not for this, there are others. He even stated in his answer that he is withholding rent because there are missing shelfs in the fridge. Any sane judge would see that he is just gaming the system.

And some people are that much of an asshole to sue in a case like that..

I am pretty sure to get a net judgment against the defendant, but probably unable to collect from the deadbeat. I am angry at the court to allow such non-sense. After the eviction, will take it to the federal court to sue the state.

I may not be a lawyer, but I'm pretty sure you are fighting both an
uphill and a losing battle. States have sovereign immunity meaning you
can't sue them unless they agree to it. Obviously this has some
limitations such as complying with Federal laws and such. But you will
be hard pressed to try to recover any losses unless you can show they
acted with malice or denied you your rights. Since your problem is that
they followed due process, you just don't like the time it takes to do
that, I think you are just shortening further the short end of the stick
you were handed.

I know. But it will still catch their attention. Defendant did not respond to Order to Show Cause (not serving plaintiff) and the Judge did not follow through with the Order. Did the judge not understanding the Order, or the Court Order means nothing. If the court erred, they should be held accountable.

Yeah, that sounds good, but there are laws that say you can't hold the
government responsible for their actions. I'm not sure what you mean
exactly by, "Judge did not follow through with the Order". If this was
brought to the Judge's attention and he tossed it off, then maybe you
have a shot. But if you expect the Judge to keep track of the
defendant's failures, that is not really what they are there for. They
do the judging based on what is brought to their attention. Nothing more..


The Order clearly say that matters in dispute are not to be considered for TWR (temporary eviction). I don't know what defendant filed with the court.. But it's not admissible without serving plaintiff. He could lie his tail off. In his answer to Appeal Court's Order to Show Answer, no valid reason for defending UD, even if he served previously. Now, defendant's game with the system renders lower court proceeding meaningless. The lower court judge has all the information to rule on TWR, but choose not to.

I'm sorry, I can't understand what you are saying. "In his answer to
Appeal Court's Order to Show Answer, no valid reason for defending UD,
even if he served previously." What does this mean? It doesn't even
have a verb...

I do understand the final sentence which seems to be the important part.
So what was the consequence of that? You mean this gives further delays?

Yes, it forced me to appeal to the District Court and waited 5 months.

This is what i am going to file:
---------------------------------

MOTION TO QUASH DEFenDant's answer and request for temporary writ of restitution

Plaintiff requested and court issued "ORDER TO SHOW CAUSE WHY A TEMPORARY WRIT OF RESTITUTION SHOULD NOT ISSUE":
"... to show cause, if any, why the Court should not issue a Temporary Writ of Restitution, allowing Plaintiff/Landlord to remove Defendant/Tenant from the rental premises ..."

"The hearing on this Order to Show Cause is not the trial on the merits. Plaintiff/Landlord may request at a later date that a trial be set ..."

"IT IS FURTHER ORDERED that the time period for Defendant/Tenant to file an answer or other response to the Complaint for Unlawful Detainer filed in this case is hereby shortened to ten (10) calendar days from the day the Summons and Complaint for Unlawful Detainer are served on Defendant/Tenant (not counting the day of service)."

For the Complaint and Order, plaintiff filed, served and provided proof of service to the court properly. The deadline for such answer expired more than 10 days before the hearing. As of this filing, defendant did not and still have not respond to plaintiff's request for the Order to Show Cause.. As a consequence, the hearing was meaningless, since there was no answer for the plaintiff to examine and nothing for the defendant to contest. The court below should have issued the Writ of Restitution immediately. Lack of such court action from below, plaintiff was forced to appeal to this court and suffers additional five months of liquidation damages.

Valid reasons to show cause include claims such as: Defendant claims ownership of property. Defendant paid plaintiff $6000 to purchase the property, rather than to rent. Plaintiff gave the property to defendant. Defendant mailed payments somewhere. Defendant paid off someone. Of course, any such claims would be subject to criminal perjury prosecution in the court of law. Defendant did not provide relevant answer and plaintiff moves the court to quash defendant's answer.

Plaintiff filed appeal to contest lower court's failure to act, due to defendant's failure to answer. This court ordered defendant to answer why there was no answer. Defendant could have blamed the post office. Defendant could have accused plaintiff of lies. Defendant could have paid off someone. Defendant did not provide any such claims either. As a result, defendant gave up the right to contest the order. Lower court should have acted accordingly and issue the Temporary Writ of Restitution.

Plaintiff already post the maximum bond of $2500, including around $3500 in illegally detained rental payments at that time, defendant could have claimed up to $6000 from plaintiff at trial. More than enough to cover all the payments made to plaintiff previously. Lower court did not consider the facts diligently, and rejected plaintiff's motion for summary judgment on the Writ of Restitution. Did the court below not understand the order? Did the court below have a different standard for plaintiff and/or defendant? Or did the Court Order not mean anything? The court below made an error in judgment and should be held responsible and liable.

Plaintiff is ready to go to trial to address defendant's allegations. Including back rents and indemnification bond, defendant can claim up to $10,000 from plaintiff. However, plaintiff cannot claim anything from defendant, since defendant is not required to put up a dime. If defendant put the illegally detained rental money in escrow and/or bond, plaintiff is willing and ready to answer any and or allegations from defendant.

Lack of any reason not to issue the Writ, plaintiff demands this court to issue the Temporary Writ of Restitution immediately.

I hope that you were not so careless as to demand anything from the judge
or court, verbally or in writing, as that is a sure way to get messed up
in the system. Pray or request normal statutory relief from your
undesired tenant who is far arrears in rent.

?-/

Not yet, i don't expect to get much out of the deadbeat and/or the court anyway. However, defendant's action, with state court sanction, enable me to file in federal court to challenge it. After TWR, works are done in State Justice and District Courts. Next step is to mark time in Federal Courts. Before TWR, time is the burden for the "plaintiff's side"; after TWR, the defense.

I want it in federal courts so the deadbeat won't just move on to AZ and CA (very likely).

BTW, is there a proper term for "plaintiff's side" vs. the defense?

 

[Joerg]

rickman wrote:

On 11/18/2014 6:39 PM, Joerg wrote:
rickman wrote:

[...]

Thanks again for the help. I had gotten off on the dual gate FET
tangent and was finding no traction because they seem to want more than
the 2 or 3 volts I have to work with. I like this a lot better but I
might try simulating one of the dual gate FETs just for fun.


The dual-gate is indeed not so great here because of the low supply
voltage.

I found a model for the BF992 and before I retire the simulations I ran
it a bit. I even dug around and found how to use the step feature to
look at the gain vs. gate2 voltage. Turns out it is not terribly
sensitive. I thought maybe it was the low power voltage and boosted it
a bit to 3.3 volts. Still not much sensitivity until Vg2 drops to
nearly zero where the gain falls off a cliff. The max gain of the
circuit with the dual gate is around 55 dB vs. 76 dB with the cascode.
Power consumption is about the same. So the dual gate FET is giving
around 16 dB gain vs. 38 dB for the cascode. But maybe even 3.3 volts
is not enough.

I'd ditch the dual-gate idea for this case. I didn't remember you had
such a low supply voltage. They are more for TV tuners.

The Cascode circuit is actually pretty simple. It is easier for me to
understand if I picture it as a common source followed by a common
gate/base circuit. Then I can visualize the operation with things I am
familiar with.

Just out of curiosity, is this ever done with a common drain as the
first FET? I expect that would certainly minimize the Miller effect and
provide the current gain needed to drive the common gate/base
transistor.


Never seen it and it would not make much sense because then the first
stage wouldn't contribute any gain. The cascode you have now virtually
eliminates the Miller effect by holding the emitter at a constant
potential of base voltage minus a diode drop.

Yes, the first transistor is providing about 12 dB of gain. In a source
follower the drain would be held at a truly constant voltage of Vdd
completely eliminating the miller effect, no?

Yes. In an ideal configuration the drain of T2 would not move at all but
there are many non-ideal parameters in the game. The finite beta of the
BJT for example. But there is a fix for almost everything, see below.

... The first transistor as a
follower yields current gain which then feeds the common base/gate
transistor which provides the voltage gain. This should also increase
the input impedance since the output voltage of the first transistor
follows the input voltage. I think this would reduce the effect of the
gate-source capacitance, no? Sort of an anti-miller effect and reminds
me of the guard rings used around sensitive inputs.

Yes, I think I have learned a lot in this. Thanks.

If you replace the BJT with another JFET you get closer to the ideal
situation. It also nets you a lot more bandwidth. See the attached file
below (correct the .lib statement back to your version).

I have a simulation of the antenna with tuning capacitance. I'm going
to look at the digital stuff for a bit but when I return to the
simulations I'll try combining the antenna with the amp.

I just hope the selectivity will be good enough or the man-made noise
low enough. Otherwise you'd have to delve into crystal filters, the
Q-multiplier or super-regenerative receivers. For example, if you
figured out a regulator loop in the FPGA and a Q-multiplier stage that
gets bandwidth-controlled by that you'd be really close to achieving
guru status


Version 4
SHEET 1 1340 680
WIRE 1008 -416 1008 -448
WIRE 1008 -256 1008 -336
WIRE 1152 -256 1008 -256
WIRE 1264 -256 1152 -256
WIRE 1008 -176 1008 -256
WIRE 32 -128 -16 -128
WIRE 128 -128 32 -128
WIRE 368 -128 368 -160
WIRE 128 -112 128 -128
WIRE 960 -112 848 -112
WIRE -16 -96 -16 -128
WIRE 848 -96 848 -112
WIRE -16 0 -16 -16
WIRE 128 0 128 -48
WIRE 368 0 368 -48
WIRE 416 0 368 0
WIRE 448 0 416 0
WIRE 608 0 512 0
WIRE 768 0 608 0
WIRE 848 0 848 -16
WIRE 368 32 368 0
WIRE 1008 32 1008 -80
WIRE 1264 48 1264 -256
WIRE 240 96 -16 96
WIRE 320 96 240 96
WIRE 768 96 768 0
WIRE 832 96 768 96
WIRE 960 96 832 96
WIRE 240 144 240 96
WIRE 368 144 368 128
WIRE 448 144 368 144
WIRE 496 144 448 144
WIRE 1008 144 1008 128
WIRE 1088 144 1008 144
WIRE 1136 144 1088 144
WIRE -16 160 -16 96
WIRE 768 160 768 96
WIRE 368 176 368 144
WIRE 1008 176 1008 144
WIRE 496 192 496 144
WIRE 1136 192 1136 144
WIRE 1264 224 1264 112
WIRE 240 256 240 224
WIRE -16 288 -16 240
WIRE 368 288 368 256
WIRE 496 288 496 256
WIRE 496 288 368 288
WIRE 1008 288 1008 256
WIRE 1136 288 1136 256
WIRE 1136 288 1008 288
WIRE 368 336 368 288
WIRE 768 336 768 240
WIRE 1008 336 1008 288
FLAG 368 336 0
FLAG -16 0 0
FLAG 32 -128 V2.2
FLAG -16 96 Vin
FLAG 240 256 0
FLAG -16 288 0
FLAG 128 0 0
FLAG 368 -160 V2.2
FLAG 448 144 Vs
FLAG 1008 336 0
FLAG 1152 -256 Vout
FLAG 1008 -448 V2.2
FLAG 1088 144 Vs2
FLAG 768 336 0
FLAG 416 0 G1
FLAG 608 0 Vin2
FLAG 832 96 Vin3
FLAG 1264 224 0
FLAG 848 0 0
SYMBOL voltage -16 -112 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR SpiceLine Rser=1
SYMATTR InstName V1
SYMATTR Value 2.2v
SYMBOL voltage -16 144 R0
WINDOW 123 24 152 Left 2
WINDOW 39 24 124 Left 2
SYMATTR Value2 AC 1
SYMATTR SpiceLine Rser=10
SYMATTR InstName V2
SYMATTR Value SINE(0 50uV 60K)
SYMBOL res 224 128 R0
SYMATTR InstName R1
SYMATTR Value 10Meg
SYMBOL cap 112 -112 R0
SYMATTR InstName C5
SYMATTR Value 100ľF
SYMBOL res 352 -144 R0
SYMATTR InstName R3
SYMATTR Value 100k
SYMBOL njf 320 32 R0
SYMATTR InstName T1
SYMATTR Value JBF862
SYMBOL res 352 160 R0
SYMATTR InstName R2
SYMATTR Value 100k
SYMBOL cap 480 192 R0
SYMATTR InstName C1
SYMATTR Value 10ľF
SYMBOL res 992 -432 R0
SYMATTR InstName R6
SYMATTR Value 100k
SYMBOL njf 960 32 R0
SYMATTR InstName T2
SYMATTR Value JBF862
SYMBOL res 992 160 R0
SYMATTR InstName R5
SYMATTR Value 100k
SYMBOL cap 1120 192 R0
SYMATTR InstName C3
SYMATTR Value 1000nf
SYMBOL cap 448 16 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName C2
SYMATTR Value 0.01ľ
SYMBOL res 752 144 R0
SYMATTR InstName R4
SYMATTR Value 10Meg
SYMBOL cap 1248 48 R0
SYMATTR InstName C4
SYMATTR Value 10pF
SYMBOL voltage 848 -112 R0
WINDOW 123 0 0 Left 2
WINDOW 39 24 124 Left 2
SYMATTR SpiceLine Rser=1
SYMATTR InstName V3
SYMATTR Value 0.5v
SYMBOL njf 960 -176 R0
SYMATTR InstName T3
SYMATTR Value JBF862
TEXT 504 -200 Left 2 !.ac dec 10 0.1 10Meg
TEXT -24 400 Left 2 !.lib spice_BF862.prm


--
Regards, Joerg

http://www.analogconsultants.com/

 

[whit3rd]

On Tuesday, November 18, 2014 5:44:02 PM UTC-8, Joerg wrote:

whit3rd wrote:

Stagger-tuned IF transformers are better [for a receiver application]

Sure, but you cannot get them for 60kHz. They only come for 455kHz and
10.7MHz, anything else is boutique stuff.

Sad, that; I could grab an old 455 kHz model from the junk box
and swap capacitors on it to make a 60 kHz unit, but the convenience
of ordering them off-the-shelf is just... gone.

Even 455 kHz is now missing from Toko catalogs.

But one can fabricate these kinds of things, and the original poster
indicated multiple frequencies-of-interest (so "modern" ceramic
filters are also unavailable off-the-shelf).

<http://www.angelfire.com/electronic/funwithtubes/IF_Can-1.html>

 

[Phil Hobbs]

On 11/19/2014 03:19 AM, Jamie M wrote:

On 11/18/2014 2:44 PM, sroberts6328@gmail.com wrote:
other hand goes through high power silica fibers.

Jamie, Start with Jeff Hecht's book "The Laser Guidebook" and
Silfvast's Book "Laser Fundamentals" before you go down this beam path.

The learning curve is extremely steep an


Hi,

Thanks, I recall hearing from previous discussions on here that glass
is opaque to CO2 laser wavelengths. I was also wondering about a
relatively cheap CO2 40Watt laser tube like this one:

http://www.ebay.com/itm/151058818267

Could the output laser beam from something like that be focused down
to a small enough spot that it would melt metal powder? If so I guess
as was mentioned already the bonding to the layer below might be
the reason a cheap 3D metal printer can't be made with these tubes,
otherwise it could be good for really high resolution small metal
parts. Maybe the concept of a "heated bed" common in plastic filament
3D printers could be used to keep the small (ie 1cm x 1cm) work area
hot enough to make the layers bond easier.

cheers,
Jamie

The issue is mostly 3-D heat conduction away from the hot spot. A
semi-infinite chunk of metal effectively drops half the delta-T across a
thickness equal to the spot diameter, so for a given delta-T you need a
power level of the order of

P >~ deltaT*alpha*diameter

where alpha is the thermal conductivity. For metal this is typically
100 W/m/K, so for a 50-micron spot (which is doing pretty well with a
CO2 laser) and a 700 K delta-T, you need about

P ~ 700K * 100W/m/K * 5e-5 m = 3.5 W.

So if you wrote slowly enough, you ought to be able to use that 40-W
laser. How slowly? To heat up a 100-micron cube would take

E = (0.01 cm)**3 * 1.7 kJ/cm**3 = 1.7 mJ, so your writing speed would be
on the order of 2000 resolution elements per second, i.e. 0.005 cm *
2000 or 10 cm/s, which is pretty slow.

These numbers are probably within a factor of 3, so you really have to
have more laser power than that for a practical instrument.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

 

On Thursday, November 20, 2014 4:02:50 AM UTC, smb...@gmail.com wrote:

> I have two 6V 1.2A power supplies, and I'd like to parallel them to get ~ 2.4A. Can you safely do that? These are identical manufacture wall warts, and I don't know anything about them other than the ratings and that it claims to be a switcher on the label.

Probably. Odds are if there's a slight V_out difference that one will deliver upto 1.2A then current limit, then the 2nd one will kick in getting you 2.4A. Probably.


NT

 

On Wednesday, November 19, 2014 7:07:24 AM UTC, Grant wrote:

Hi,
Would you ever design such a wiring loom as this?
http://media.englishrussia.com/newpictures/Russian-military-factory-Sheglovski-Val-or-Sheglovs-Earthwork/1623286_900.jpg
or <http://goo.gl/D571Qv
Yeah, fault-finding would be so easy...
Nope.
Grant.

It must be fault tolerant.

But no, its bonkers. 1970s technology attached to whatever that huge array is.


NT

 

[Jasen Betts]

On 2014-11-20, smbaker@gmail.com <smbaker@gmail.com> wrote:

I have two 6V 1.2A power supplies, and I'd like to parallel them to
get ~ 2.4A. Can you safely do that? These are identical manufacture
wall warts, and I don't know anything about them other than the
ratings and that it claims to be a switcher on the label.

if they're mot regulated it's probably work ok.
otherwise probably not.

--
umop apisdn

 

[Jasen Betts]

On 2014-11-20, dakupoto@gmail.com <dakupoto@gmail.com> wrote:

Could some electronics guru pleas explain what
a "self-ballasted" LED lamp mean ? I have seen
LED lamps, running off the AC line, and powered
by a simple small 5V 1 Amp SMPS, but what exactly
does a self-ballasted LED lamp mean ?

It depends on the context.


possibly it has a resistor inbuilt for operation at some specified
voltage.

--
umop apisdn

 

[BackInTheUSSR@nullnut.rut]

(M)ulti (F)unction phased array (R)ADAR, Gospodin Rickman,

Having worked for some time on a Lithuanian project, all I can say is the Former All Soviet Standard (GOSPLAN) wiring scheme is first rate. The wire is good, the standard is good. The civilian RF connectors are fine, very BNC or SMA like.

However, when you use their older Mil-Spec connectors, you question why you bother. Assembling them is an Art Form, compared to the simplicity of Cannon/Amphenol Plugs. Not really designed for multiple connect/disconnect cycles. Designed for absolute minimum cost, and assembly is laborious.

However, as you all have guessed those green "CA" connectors pictured are just a little bit better then Jones Plugs. Very fragile to handle, which is why all wiring that uses them is clamped or shock proofed, religiously. Once assembled its decent and ensures contact. But the harness will be mounted in such a way to ensure it has very little tension on it. The connector in question is long obsolete.

Steve

 

[Martin Brown]

On 20/11/2014 03:40, dakupoto@gmail.com wrote:

Could some electronics guru pleas explain what
a "self-ballasted" LED lamp mean ? I have seen
LED lamps, running off the AC line, and powered
by a simple small 5V 1 Amp SMPS, but what exactly
does a self-ballasted LED lamp mean ?

In series with something that approximates a constant current source for
some reasonable range of applied input voltages. Could be as simple as a
crude ballast resistor or a semiconductor based device.

A bare LED has a rather rapid increase in current through it once it
starts to glow with a slightly higher applied voltage leading vastly
increased current and then total destruction if you go too high.

You can do some cute physics experiements plotting V-I curves for LEDs.
eg.

http://www.phys.uconn.edu/~hamilton/phys258/N/led.pdf

Expect some LEDs to be destroyed in this practical.

--
Regards,
Martin Brown

 

[Piotr Wyderski]

Martin Brown wrote:

> A bare LED has a rather rapid increase in current

Like any other PN junction: I(U) is exponential.

Best regards, Piotr

 

[legg]

On Wed, 19 Nov 2014 18:07:19 +1100, Grant <omg@grrr.id.au> wrote:

Hi,

Would you ever design such a wiring loom as this?

http://media.englishrussia.com/newpictures/Russian-military-factory-Sheglovski-Val-or-Sheglovs-Earthwork/1623286_900.jpg

or <http://goo.gl/D571Qv

Yeah, fault-finding would be so easy...

Nope.

Grant.
You're just reacting to the scale and technology used.

Similar complexity is present in semiconductor large scale integration
or optical interfaces. It's there, but you just don't notice it except
perhaps as a more frequent junking of some device that used to last
for decades.

Some applications simply defy miniaturization. Some will never last
long enough to justify the effort. The first attempt is often the
end-run, trying to avoid the need for so many individual terminations.

RL

 

[Martin Brown]

On 20/11/2014 05:40, jurb6006@gmail.com wrote:

On a forum, I read this :

"I am the proud new owner of a 2270. It seems to be in pretty good shape, but I noticed today that it seems like all the radio stations at once are coming from the left channel. The volume knob doesn't affect it, as it is the same level no matter where you turn it to. Changing the input selector doesn't help, and neither does moving the tuner. What is going on? "

Sounds more like local taxis breakthrough on the power amplifier to
speaker lead. A signal that doesn't depend on the input selector or
volume control isn't going through either!

The thread contiues with some details, these are FM stations. I can understand if it is AM, but FM ? He says it is about ten stations all at once, though that is probably subjective, it could be "only" five.

I can't see any way that normal FM channels could appear only on the
left channel of a stereo pair. In all the places I know they transmit
stereo as L+R and L-R except in Japan during bilingual news
transmission. (When L+R = Japanese and L-R = English)

What, in a regular audio reciever could demodulate multiple FM staions up in around 100 mHz that have a measely 75 kHz deviation ?

Could this have something to do with this digital stuff in the signal now ?

I shudder to think how this could happen as described unless there is
something else present causing massive intermodulation distortion.

--
Regards,
Martin Brown

 

[John Larkin]

On Wed, 19 Nov 2014 20:02:44 -0800 (PST), smbaker@gmail.com wrote:

>I have two 6V 1.2A power supplies, and I'd like to parallel them to get ~ 2.4A. Can you safely do that? These are identical manufacture wall warts, and I don't know anything about them other than the ratings and that it claims to be a switcher on the label.

It might work; one could current limit and the other one supply the
rest of the load current. Try it; nothing bad is likely to happen.

Some of these wart supplies current limit by shutting down for a while
and retrying. Those types won't work in parallel.

You could also get a 6V 3A wart cheap.


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Jim Thompson]

On Wed, 19 Nov 2014 20:02:44 -0800 (PST), smbaker@gmail.com wrote:

>I have two 6V 1.2A power supplies, and I'd like to parallel them to get ~ 2.4A. Can you safely do that? These are identical manufacture wall warts, and I don't know anything about them other than the ratings and that it claims to be a switcher on the label.

Try it, with a fire extinguisher at hand.

Unless they are PERFECTLY matched, one will try to supply all the
current and the other will pretty much shut down.

You could try "ballast" resistors from each to a common output, with a
resulting voltage drop.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice480)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.

 

[Joerg]

rickman wrote:

On 11/19/2014 8:52 PM, Joerg wrote:
rickman wrote:
On 11/19/2014 7:19 PM, Joerg wrote:
rickman wrote:
On 11/19/2014 1:47 PM, Joerg wrote:
Joerg wrote:
rickman wrote:
On 11/18/2014 6:39 PM, Joerg wrote:
rickman wrote:

[...]



On more hint: It's best not to amplify low frequency spectrum that
you
don't need because that contains a lot of crud, too much chance for
powerline stuff to modulate in. You could reduce C1 and C3 to
0.022uF to
curb that.

Yes, I'm aware of that. I put those caps on the high side just to
push
them out of the way of seeing what is going on. Although I was
tuning
them a bit last night and couldn't figure out what was going on. They
appeared to be acting as if they were much smaller than what I was
using... by about 100x. As I read more of the posts and someone
mentioned the Miller effect again, I realized the drain bypass
capacitor
sees a similar effect, but opposite in sense. So with a gain of
100x I
need 100x larger cap!


If the resistance in the source path drops for a gain change the
capacitance has to increase accordingly, otherwise it shouldn't have
to.
0.022uF should be good in you scenario.

What I mean is that if I calculate a value for a capacitance from the
corner frequency, the value I get is 100 times too small. C=1/2pi*R*f
Because this part is in both the input and the output paths the gain
magnifies the impact of the capacitance. Right now I am simulating with
4.7 nF which gives a nice peak in the ballpark of the frequency range I
am looking for. But if I use the simple calculation, 1/2pi*R*C = 338
Hz. Looking at the response curve for the source voltage it is about -6
dB at 60 kHz when it should be more than 40 dB down. Clearly
*something* is going on.


I don't quite follow there. The caps to ground are essentially shorts
for RF. IOW the FETs in your circuit operate with hardly any
degeneration, pedal to the metal. If you had resistors in series with
them then you could more precisely set the gain because it will be
determined by the ratio of the drain resistor (including load) and this
new series resistor.

The cap is a short only to a first order approximation or as a limit as
the frequency goes up. Closer to the corner frequency formed by the cap
and the bias resistor it is significant and rolls off the gain. When I
try to calculate that corner frequency is is off by more than 100x,
50kHz+ compared to the 338 Hz I calculate. Is this part not clear?

Normally one does not calculate RF amps at corner frequencies as that
can result in major production tolerance issues. The 10uF you have in
there lets the first amp level off to full gain at 10Hz. That's a recipe
for major line interference.

Maybe I'm looking at it backwards. The corner frequency I am
calculating is more likely the point where the roll off flattens out to
0 dB. Yes, the gain of the first stage flattens out with a 3 dB point
of 351 Hz, close enough to 338 Hz.

The corner frequency I thought I was calculating would be the point
where the impedance of the bypass cap becomes large enough to impact the
gain of the FET with is more about the drain resistor than the source
resistor.

Corner frequency really does not matter here. Just calculate it so the
60kHz is in the flat part. 0.022uF is a good start, assuming you don't
intend to listen to anything below 20kHz. VLF reception would be another
story.

If you want more repeatable and flat gain you'd have to place resistors
in series with C1 and C3. Of course that will lower overall gain.

I'm not serious about the dual gate FET. I just thought as long as I
have the simulator out I might take a look just to see how they do.


It's always good to learn about those because one can do weird tricks
with them. They are also useful as gain control elements. I just hope
they won't disappear. I think TV will eventually vanish and go Internet
and then they'd likely be obsoleted because that is the only mass
market
for them that I know of.

I can't see TVs ever loosing a tuner.


I meant mankind losing TVs, not just the tuner. Meantime, the tunerless
TV is almost reality. Some people in our neighborhood get their TV via
IP, through a CAT5 cable. No antenna, no dish, no coax from the cable TV
company.

But they still use a TV. ...

Their parents and grandparents do.

... Sure, if you are cable, which most people are,
and use a cable box you have no need for a tuner.

That's how it was 15 years ago. Neighbor's kids were constantly in front
of the TV. Now you don't find them in the living room anymore even
though the big screen TV is now way bigger than ever and with surround
sound. They are in their rooms or on a distant couch incessantly tapping
out text messages.

... But even if there are
only 1% of the consumers using an antenna port for something, that is
enough to make a squawk. I guess it is more about how many sales they
think they may loose vs. the cost. That cost is very small, so it
doesn't take many lost sales to cover $0.50 worth of parts. Even then I
doubt that have a good way of measuring it, so they have FUD. But once
the first company bails on the antenna port, you can expect them all to
follow quickly.

Eventually they will.

... That would only happen when TV
station broadcasts go away and I don't think that is at all on the
horizon.


The writing is on the wall, they'll gradually go the way of newspaper
agencies.

But there are still plenty of newspapers too...

But in what condition? Our only remaining paper is left-leaning which I
despise but have to swallow. They sobered up a bit on propaganda because
else they'd lose even more subscribers so it has become somewhat
bearable. The business section has been reduced to two pages and is now
behind the obituaries. From the contents it is rather obvious that they
no longer employ their own analysts. It's a far cry what what this
newspaper was 15 years ago.

Others have vanished completely. For example, every time I am flying I
try to find a Spanish language newspaper at stop-over airports, to learn
the language. Nada, zilch. They are all gone. One seller told me that I
should have come 10 years ago.

Digital TV was a mistake. Many stations gave up VHF without a
fight and now we have situations like here where stations pixelate out
all the time unless you have cable or satellite.

Yes, I fell off the digital cliff. My place in Frederick, MD is only 50
miles from DC, maybe less as the crow flies. But the only TV station I
can get now is MD public TV which is some 20 miles closer. Not that I'm
complaining. The loss of network TV was one of the best things to
happen in my life. really!

See? You are thinking like us now. Yet we are both middle-class families
and, therefore, exactly what advertisers want to reach. So they must
move away from TV and onto the Internet and that's exactly what is
happening.

So people like us are
watching substantially less TV than five years ago. What little we view
is all taped because one never knows when it's pixelating out, it often
takes 3-4 attempts to record a movie without signal failure. On the
upside this allows us to fast-forward through all the ads (except the
Hershey ad, I like that one). Longterm it all means less viewers and in
consequence less ad revenue. You can see it in the staffing, many
stations have reduced and have folks doing essentially two jobs.

Here at the lake I have *no* TV. But I have discovered the nefarious
sites that provide all sorts of past and present TV shows. It's funny
how the ads all try to take over your browser and trick you into
installing crap. IE actually is the current best browser to blocking
that stuff. Mostly I get a note at the bottom of the screen saying a
pop up was blocked.

With Firefox I don't even get those messages anymore. I have a li'l
dashboard where JS and all that is normally turned off. I only turn it
on if I use teleconferencing or when I really have to use a particular
site. Else I just move on if a site is too intrusive.

But even worse is the trend you can observe with kids because in less
than 10 years those will be the folks courted by advertisers. Many kids
I know have zero or almost zero interest in TV. They do not watch
ballgames on TV, no news, no shows. They get their news via Internet and
mostly through some social media sites. For movies they resort to
Netflix and similar services, if they care at all. And that's it, that's
their media consumption. The rest is all staring and pecking at a smart
phone. Ok, I am exaggerating a bit here but I clearly see this trend.
It's going to happen.

I have no doubt, but not very soon. The question is not how soon will
those kids grow up, but how soon the rest of us will stop doing what we
are doing either because we change or die. lol

It's a matter of only a couple of decades, maybe three. I predict that
by then TV will have shriveled to a tiny fraction of what it is now and
there will be carpal tunnel cases (thumb joints) of almost epidemic
proportions, along with major obesity and other issues that are
consequences of a sedentary lifestyle at young age.

I mean, they still support dial pulses on the phone line... if you
*have* a phone line.

We do. And we have a working (!) 1927 Western Electric wall phone in the
kitchen. Of course, the crank is disabled but when that thing rings
everyone in the house stands at attention.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[DecadentLinuxUserNumeroUn]

On Thu, 20 Nov 2014 01:51:36 +0000, Paul E Bennett
<Paul_E.Bennett@topmail.co.uk> Gave us:

DecadentLinuxUserNumeroUno wrote:

On Wed, 19 Nov 2014 14:02:53 -0700, Don Y <this@is.not.me.com> Gave us:

Hi,

I'm reviewing stats for some execution times (which imply data transfer
rates) of some utilities I'd run previously on laptops and, from that,
see what I can only attribute to lousy disk subsystem performance.

Granted, laptop drives tend to be less performant simply because
of power and space considerations (and, the Windows disk access
patterns). And, of course, laptops are all over the map in terms
of price/performance.

But, what sort of unbuffered,[1] single sector performance are you
likely to encounter in that environment? E.g., a desktop disk can
easily saturate a 100Mb link -- or a USB2 PCI i/f. I'm not sure
that is true with many (?) laptop drives...

I realize the 2.5" form factor (nor the PATA/SATA distinction)
should arbitrarily limit performance (though low RPMs can). E.g.,
I have some 2.5" drives that will do 300MB/s easily (though run
very warm and draw twice the power of "typical" drives)

Thx,
--don


[1] Of course, all disk accesses are buffered -- in several places.
My point is "without taking explicit and extraordinary measures"...


10,000 and 15,0000 rpm SAS drives.

Better... Solid State... duh. mSATA and M.2 mini-PCIe are
the screamers these days. Literally 100s of MB/s even over USB links.
Some laptops have a socket in them.

The Solid State SATA drives I have installed in my Gigabyte Brix PC claim a
transfer capability of 6Gb/s. Not sure I could fill the DDR3 memory that
fast though.

The tests are things like having multiple partitions on the same drive
and then copying a big 20GB movie file from one to the other.

It gets done in chunks and the copy or move routine manages that, but
it all has to go through the memory a couple times as the open file gets
written to and built up with a running check code to keep from having to
read the file again.

I notice small stuff... like when more than one file is selected, the
entire copy runs at one low rate (on mine that was some 70MB/s) thru the
whole thing.


When a single large file is selected, it "bursts" several hundred
megabytes at about 140MB/s for just a second or so, and then drops to
the low rate for the rest of the process.

Then, I found a neat trick and some insight as to what takes place
with these really big files. I used "move" instead, and it "bursted" at
a super high 1+GB/s rate and then dropped to like 180MB/s for the rest
of the move. So I concluded that the "move" code was probably actually
done well (better than the copy code) and could be relied on for good
numbers. I need to get a second SSD in there and see what the physical
volume to physical volume speeds are. They should be far higher, since
the other way was all partitions residing on the same physical drive.

Oh... darn... that is my spinning drive I did all that with.
Please take note.

The SSD in that box is my OS drive and I will not be taxing that like
this. I am sure Windows hits them way too often as it is.

So, when I get two more SSDs to put in there, I can refer to those
numbers. I do intend to do that as well.

 

[Tim Williams]

"legg" <legg@nospam.magma.ca> wrote in message
news:26qr6a9nfcf0dehq7rotu3tpc4an1jq24g@4ax.com...

Similar complexity is present in semiconductor large scale integration
or optical interfaces. It's there, but you just don't notice it except
perhaps as a more frequent junking of some device that used to last
for decades.

Some applications simply defy miniaturization. Some will never last
long enough to justify the effort. The first attempt is often the
end-run, trying to avoid the need for so many individual terminations.

Compactrons come to mind.

I've got to imagine tubes could be pretty slick these days with MEMS.

If they had MEMS back in the day, they could've done some really neat
stuff, integrated TV receiver - demodulator - chroma separator, say.

Of course... "neat stuff" would include transistors, so we'd still be
where we are today without the glowbugs. :^)

Tim

--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com