Driver to drive?

[Tim Wescott]

nick wrote:

i am a beginner
"nick" <ucheng4@csc.cuhk.edu.hk> źśźgŠóślĽóˇsťD:1104029171.458387@jupiter.cse.cuhk.edu.hk...

thx




The ARRL Handbook, most recent edition. RSGB Handbook, same.

"Radio Frequency Design" by Hayward.

Any appropriate title by Ulrich Rhode (but you should probably start
with Hayward).

"Experimental Methods in RF Design" by Hayward, Campbell and Larkin. I
haven't read the book, but I've seen it highly recommended.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Active8]

On Sun, 26 Dec 2004 12:53:43 GMT, Kevin Aylward wrote:

This is why I use a common mode feedback feeding extra emitter followers
in http://www.anasoft.co.uk/Mospoweramp2.jpg. The two stage gain amounts
to the order of 160db gain. The 130db of feedback at low frequencies
gets one rather low distortion

Interesting circuit. You mean the common mode feedback going to the
active loads on the input pair?

I'd like to hear your explaination of the next stage. I'm only
halfway understanding its operation. Looks like emitter followers
with an improved Widlar current mirror at the emitters. Cascode
outputs with all that surrounded by the miller caps. Looks like the
feedback current out the bottom of all that bucks the current in its
respective diff input branch.

--
Best Regards,
Mike

 

[Nico Coesel]

John Larkin <john@spamless.usa> wrote:

If it's only 2 layers and has no ground plane, and power and ground
are just skinny routed traces, I'd be astonished if it actually
worked.

You'll be amazed what can be accomplished by using only 2 layers if
the bypass capacitors are well placed and the power is well routed. I
actually have a 2 layer 386SX 33MHz motherboard which was available
commercially (not my design, just something that ended up in a box
with PC stuff).

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl

 

[John Larkin]

On Sun, 26 Dec 2004 19:14:16 GMT, nico@puntnl.niks (Nico Coesel)
wrote:

John Larkin <john@spamless.usa> wrote:


If it's only 2 layers and has no ground plane, and power and ground
are just skinny routed traces, I'd be astonished if it actually
worked.

You'll be amazed what can be accomplished by using only 2 layers if
the bypass capacitors are well placed and the power is well routed. I
actually have a 2 layer 386SX 33MHz motherboard which was available
commercially (not my design, just something that ended up in a box
with PC stuff).

Yeah, but it takes some luck, and maybe a few iterations, especially
in a mixed-signal design with fast parts, like this is. And if it's
autorouted, a lot of the traces will make the grand tour of the board.
It might work, or it might be a nightmare.

Moderm PCs have a lot of layers... anybody know how many?

John

 

[Active8]

On Sun, 26 Dec 2004 20:18:40 GMT, Ben Bradley wrote:

The pot with wiper to the base bothered me, because I recalled
reading about the possibility of the wiper opening up and causing Bad
Things to happen. I looked ii up, and it turns out it's by the same
author, on this other page:

http://sound.westhost.com/amp_design.htm#bias_servo

It's a small internet. That's a good idea - testing the spkrs. I

hope they're all close, though. Don't need a spkr dependant amp.

It looks like unless I purchase those papers Win mentioned, I can
flog Spice all day long and get nowhere.

--
Best Regards,
Mike

 

[John Woodgate]

I read in sci.electronics.design that Kevin Aylward
<salesEXTRACT@anasoft.co.uk> wrote (in <rvyzd.56612$ef5.4072@fe1.news.bl
ueyonder.co.uk&gt about 'active collector loads (audio freq)', on Sun, 26
Dec 2004:

The 130db of feedback at low frequencies
gets one rather low distortion

Until the signal reaches the end-stop, of course. x volts out,
distortion 0.00...1%. (x + 0.1) V out, distortion 1%. (x + 1) V out,
distortion 30%. (All voltages r.m.s, of course)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

Bill B. is intrigued with the concept of electrically small ("energy
sucking") antennas. It seems to me the ferrite, the multiple turns,
and they're capacitance render the space occupied by the antenna
of much lower impedance than the surrounding space, rendering
it "energy sucking".

Actually, I'm fascinated by the "microscopic" analysis of antennas.

Go and study what happens to the EM fields and the individual
charges, moment by moment. Try to *see* the operation. Be
a concept-loving 'babylonian' rather than a math-loving 'greek.'
Textbooks go for the frequency-domain calculation-based approach.
I want to be able to visualize the shape of the EM fields in the
antenna's nearfield under various conditions.

This is analogous to giving up on Ohm's law and instead
examining the shape of e-fields and the behavior of carriers
in a conductor. Ohm's law is great for circuit design, but
the simplification it brings will conceal all sorts of
interesting and complicated phenomena. For engineering,
use Ohm's law, but if you want to tear off the hood and
look at the details of the physics, then Ohm's law *is* the
hood that needs to be torn off. Same with antennas: to
confront the physics, we have to carefully remove the mental
models which simplify everything and which make engineering
easy.

When I started understanding what the nearfield looks like,
I soon found out about "energy sucking" antennas, I realized
that my intuition was right: the frequency-domain approach hides
some very interesting phenomena. If we start looking at 3D
fields and electron density while ignoring the EM spectrum and
the whole Impedance concept, we gain some insights that don't
appear in textbooks. Suddenly a superregen receiver is an
obvious device. Suddenly the tuning capacitor across your
AM radio ferrite coil is an obvious technique. Lasers stop
looking so much like QM devices and have obvious connections
with classical EM. And suddenly the Sutton/Spaniol antenna
becomes a very cool discovery (and why are only the Fringe
Science types discussing it?)

----

If I had some real math skills, I'd love to look at antennas from
the viewpoint of photon tunneling. Because of tunneling,
antennas have access to any photon within approx 1/4 wavelength
distance. This might do nothing but make antenna physics
excruciatingly complicated. But with luck it will reveal some
interesting physics of which nobody else is currently aware.
Or it might highlight some antenna designs which aren't currently
known.

 

[Guy Macon]

richard mullens wrote:

The binding on my first edition is just fine.

You obviouly don't use it as much as I use mine.

 

[Hal Murray]

Moderm PCs have a lot of layers... anybody know how many?

I think the mother boards are typically 4 layers.

They work pretty hard to get there - lots of competition in that business.

The board designers do get some help from the chip designers - sensible pinouts.
(Basically, the chip designers have to demonstrate that you can build a sensible
board with only 4 layers.)

--
The suespammers.org mail server is located in California. So are all my
other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited
commercial e-mail to my suespammers.org address or any of my other addresses.
These are my opinions, not necessarily my employer's. I hate spam.

 

[RST Engineering (jw)]

But you don't understand. The old DOS program will only output a printer
file that is intended to go to a camera for photo shooting. Nobody any more
takes camera art and shoots it to make boards. Everybody wants gerbers/NC.
The old DOS program will NOT output gerbers/NC.

I need a translation from this old DOS program to gerbers/NC for a lousy
couple of dozen boards.

Jim



"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:FbydncPztIk9slLcRVn-1Q@rcn.net...

RST Engineering (jw) wrote:

 

Why are you making a PCB if all that is going on it is a single LED? It
would be more efficient to mount the LEDs in some kind of fixture (e.g.
a matrix of holes drilled in a piece of metal, wood or styrene).
Although you can etch a PCB to do this (I recommend Olimex,
www.olimex.com, for this, since they charge by panel area rather than
by number of PCBs). Or you could build it on snippets of regular matrix
board. But as I said, I don't understand why you need a PCB for this
application.

 

[Tim Williams]

"Chuck Harris" <cf-NO-SPAM-harris@erols.com> wrote in message
news:zY2dnSXvk8nA6lTcRVn-tg@rcn.net...

That's nice Tim. What you are touting as a great advantage (lack of
permissions)
is the Achilles heel of 'doze.

Unless you use it for personal computing... which just so happens to be 90%
of the sales which M$ goes to...... but I digress...

Tim

--
"I've got more trophies than Wayne Gretsky and the Pope combined!"
- Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms

 

[keith]

On Sun, 26 Dec 2004 18:02:30 -0600, Hal Murray wrote:

Moderm PCs have a lot of layers... anybody know how many?

I think the mother boards are typically 4 layers.

Most these days are six. The low-end stuff is still four though.

They work pretty hard to get there - lots of competition in that business.

Sure. The only ones making money are the one's making the processor and
the OS. Smart people don't fun M$. ;-)

The board designers do get some help from the chip designers - sensible
pinouts. (Basically, the chip designers have to demonstrate that you can
build a sensible board with only 4 layers.)

Again, many are six-layer to get the wiring reasonable. Server boards are
almost always six layer.

--
Keith

 

[richard mullens]

Guy Macon wrote:

richard mullens wrote:


The binding on my first edition is just fine.


You obviouly don't use it as much as I use mine.

I'm sure that you're right - Mostly I just make the occasional device with a microcontroller (AVR).

I guess that there is a spectrum of usage - and for some a paperback edition would be just fine (and more to the point cheaper !)

 

[Leon Heller]

"RST Engineering (jw)" <jim@rstengineering.com> wrote in message
news:10su6obgp98hd4d@corp.supernews.com...

A very, very long time ago, I bought the original DOS version of Easy-PC
out of an ad in Ham Radio magazine. With all respect to the current
product, that old DOS sucker was about the buggiest thing this side of
Microsoft.

At any rate, the LAST board I laid out in the Easy-PC is about at the end
of it's mercifully long (20 years or so) life but I need a few dozen more
boards to match up with a few hundred dollars worth of metalwork so as not
to waste metal. The PC board house that made the last run of boards told
me that this was the end, that they couldn't set up for photo negatives
any more.

The old DOS program will NOT run under Windoze, no how, no way, no sir.
I've tried every trick I know of and it still jams on loadup (even AFTER I
get it out of its original 5" floppy format). However, the trial version
of Easy-PC 8 loads the old board just fine. The only problem is that it
will give me a PRINT version only, no Gerbers. My current PC board house
can only work from gerbers -- they put their camera into storage ten years
or so ago.

The point being:

1. Does anybody have a version of Easy-PC that gives gerbers/NC files and
would be willing to do a quick import and export of files for me? I
promise, no more requests if I can get this one job done.

I've got the latest version of Easy-PC. I'll generate the Gerbers for you if
you email them to me.

Leon
--
Leon Heller, G1HSM
leon.heller@dsl.pipex.com

 

[John Larkin]

On Sun, 26 Dec 2004 12:33:27 -0800, "Richard Henry" <rphenry@home.com>
wrote:

"John Larkin" <john@spamless.usa> wrote in message

Moderm PCs have a lot of layers... anybody know how many?

Did you mean modern, or modem?

Modern. Funny, I bet I've written a few million lines of code and at
least a hundred manuals, and I've never learned to type.

John

 

[Richard Henry]

"John Larkin" <john@spamless.usa> wrote in message
news:me4vs0t3sub385ct61tvl6jkjvj537avet@4ax.com...

On Sun, 26 Dec 2004 12:33:27 -0800, "Richard Henry" <rphenry@home.com
wrote:


"John Larkin" <john@spamless.usa> wrote in message


Moderm PCs have a lot of layers... anybody know how many?

Did you mean modern, or modem?


Modern. Funny, I bet I've written a few million lines of code and at
least a hundred manuals, and I've never learned to type.

Most mispellings won't pass by a compiler. Tragically, some will.
\

 

[John Perry]

Michael Black wrote:

....
Cookbook with 1974 copyright. Even better, he used the concept in his
Psych-Tone in the February 1971 issue of Popular Electronics, page 25,
to generate random musical tones. (But I see nothing in his RTL Cookbookb
from 1969)

My copy of S. W. Golomb's _Shift_Register_Sequences_ is copyright 1967, and
his reference list goes back to 1801 (abstract algebraic theoretical
underpinnings), with obviously applicable references to 1953.

I happened upon Golomb's book while researching background material on that
same HP Journal article (for other purposes), which described a
pseudorandom-modulated probe signal that increased the range and accuracy
of one of their time-lapse-detection fiber optic test equipments.

I, too, seem to have lost the original hpj article and all direct references
to it.

--
j point e point perry at
cox point net

 

[xray]

On Fri, 24 Dec 2004 06:16:55 +0000, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that Winfield Hill <hill_a@t_rowland-
dotties-harvard-dot.s-edu> wrote (in <cqfv8102hmk@drn.newsguy.com&gt
about 'Suggestions for AoE 3rd Ed.', on Thu, 23 Dec 2004:

Right. We told our publishers the binding needs to be improved. But
they were surprised; apparently most books don't get such heavy use.

You have to allow for it to be thrown at the wall (or the boss) when
even its sage advice doesn't solve the problem. (;-)

I think the mass and basic aerodynamics are about right for that, but it
is another reason to consider stronger spines.

I agree about the binding getting stressed by those of us who find it a
good practical reference (even if never flung toward those that might
need educating).

 

[Kevin Aylward]

Active8 wrote:

On Sun, 26 Dec 2004 20:05:42 GMT, Kevin Aylward wrote:

Jim Thompson wrote:
On Sun, 26 Dec 2004 12:50:06 -0500, Active8 <reply2group@ndbbm.net
wrote:

On Sun, 26 Dec 2004 12:53:43 GMT, Kevin Aylward wrote:

This is why I use a common mode feedback feeding extra emitter
followers in http://www.anasoft.co.uk/Mospoweramp2.jpg. The two
stage gain amounts to the order of 160db gain. The 130db of
feedback at low frequencies gets one rather low distortion

Interesting circuit. You mean the common mode feedback going to the
active loads on the input pair?

I'd like to hear your explaination of the next stage. I'm only
halfway understanding its operation. Looks like emitter followers
with an improved Widlar current mirror at the emitters. Cascode
outputs with all that surrounded by the miller caps. Looks like the
feedback current out the bottom of all that bucks the current in
its respective diff input branch.


Looks to me like Kev got overwhelmed with his own BS ;-)

Nonsense.


130dB feedback... ROTFLMAO!

It does do 130db of feedback at LF, according to spice. Its two
stages of cascode amplification. 160 db of gain is 2 of 80db. This
is 2 of 10,000. A non cascode stage might do Va/Vt = 50/25m = 2000.
So, a cascode can certainly get 10,000 in one stage.

I take back that part about the Wilson mirror. The other half has
the same circuit so it's just 3 emitter followers.

How many MOSFET models in SS are accurate in the sub-threshold
region? Surely none you've just dropped in from the manufacturer. If
it's as bad as Win suggests, I may as well forget expecting any
Spice results to be accurate.

Yes and no. BSim3 models are usually quite accurate in all regions, if
you can get the correct models. However, small signal distortion analyis
is not supported for them in spice.

I'd like to find some good models for audio power.

One cheats.

SS has two set of models for the EC10N20 and EC10P20 range. One is a
kludged BSim3 (EC10N20 and EC10P20) one is a level 1 (EC10N16 and
EC10P16). Both are set up to approximately match each other especially
the capacitances. I do runs with each type to check stability, and use
the level 1 for small signal distortion.

If one is not in subthreshold, the level 1 will give results that are
"reasonable". Who cares if its 100% in error if one is designing say at
0.01%. What one is trying to do is know that the distortion is not 0.1%
if one is after 0.01%. So, if one wants say 0.002%, one tries to get
spice to show its better by a factor of, say two. Engineering is not
exact, but one can still work around this with guestimates.

I can send you the SS files for the amp if you want.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.