Driver to drive?

[Spehro Pefhany]

On Tue, 05 Oct 2004 20:38:26 GMT, the renowned Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hi Spehro,

They are in ceramic DIP, probably kept in production for military
applications that don't mind the cost.


The SOIC is only around 25 cents US. Still quite a bit for four flip
flops. But LS stuff as the OP was requesting will likely become ever
harder to obtain so it makes sense to migrate the design at least to HCT
if he can. It it isn't running fast I'd see if it can be done in the
4000 series. That has enjoyed a product life almost like the VW Beetle
and is cheap.

The HC series is very much available in the simpler functions, wheras
I think the HCT stuff is well on the way out, so that's another option
(requiring a bit of care regarding the inputs, of course)


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Wim Ton]

"Johan Karremans" <johankarremans@hotmail.com> wrote in message
news:26d2168f.0410050419.255e7d50@posting.google.com...

Can somebody tell me what the substitute ic is from ic 74LS173.

Maybe you can build one in a PAL or GAL

Wim

 

[john jardine]

"Rich Grise" <null@example.net> wrote in message
news:wDm8d.4345$cd1.1746@trnddc03...

[-]

Speaking of references, who spotted the Alien skull in Predator 2 before
they announced it all over the place?

Thanks,
Rich

I did!.
Blinked twice as the camera passed that trophy display. I'm easily amused by
sly stuff like that.
Also enjoy spotting writers sticking the occasional dialogue line in from
some obscure film I've also seen, or identifying minor prop parts that have
been recycled from elsewhere.

(This markedly On-Topic post hereby marks JJs first ever use of his new
fangled, broadband, internet thingy. Golly, it aint arf fast!.)
regards
john

 

[Mike Monett]

ChrisGibboGibson wrote:

John Larkin wrote:

[snip]

Comparing the results with a 10 digit meter I got accuracy within 0.005% of
the
Vrefs I was using. That's quite amazing for a dollars worth of comparator
and
discretes.

10 digit DVM? Who makes that?


Keithley, circa early 80s

Gibbo

Model?

Mike Monett

 

[Winfield Hill]

ChrisGibboGibson wrote...

Spehro Pefhany wrote:

Doesn't take much leakage across the capacitor or current source to
reduce the linearity at midscale down to the 12-bit level though.

I might have known you'd spot the flaw!

Some leakage, but dielectric absorption is usually more damaging.


--
Thanks,
- Win

(email: use hill_at_rowland-dotties-org for now)

 

[Winfield Hill]

Mike Monett wrote...

ChrisGibboGibson wrote:

John Larkin wrote:

[snip]

Comparing the results with a 10 digit meter I got accuracy
within 0.005% of the Vrefs I was using. That's quite amazing
for a dollars worth of comparator and discretes.

10 digit DVM? Who makes that?

Keithley, circa early 80s

Really? 6.5 and 7.6 or even 8.5 digits, but 10 digits?

Note, 6.5 or 7.5 digits lets one measure to better than 1ppm
resolution, yet 0.005% is only 50ppm, or 5.5-digit territory.


--
Thanks,
- Win

(email: use hill_at_rowland-dotties-org for now)

 

[Joerg]

Hi George,

The abrupt shut-off would be of no concern if you stop using the PLL
just before that event. It should be no problem because the length of
the transmission is under your design control so the receiver would
"know" when to quit logging the PLL.


Joerg, I think you're saying that a PLL with small noise BW would be
useless to detect the sharp OFF transition in the waveform, so you
gotta get it out of there at the right time and use something else
that can detect the sharp OFF transition quickly.

The PLL would not detect the sharp OFF transition, it would not be very
suitable for that. The PLL would detect the exact phase position of the
sine wave. Something else would have to detect the ON or OFF transistion
but that is rather easy because for that you only need a few hundred
usec precision. The PLL would do the fine stuff. But again, I'd first
look into zero crossing techniques. I have only done these at much
higher frequencies above 2MHz but it didn't require a lot of hardware,
just good low noise design.

I'm starting to think that the way to go is to use a DSP to first lock
on to the tone like a PLL, then to look at the tone in, say, 50 nsec
time slices and detect when the waveform drops below the value that
the DSP predicted would occur based on the waveform's history. That
would mean it's headed south fast, and that's the OFF event needed for
timing reference.

I don't think determining a 50nsec accuracy with the ON or OFF events is
going to work. You really need to determine the exact position of the
phase of your 1KHz signal.

Yet another approach is to send out a unique binary sequence and run
a matched digital filter against it. There are several codes that are
used for this purpose and probably someone makes chips with such a
code and filter built in. That would give you absolute (time of onset)
and relative (50nsec spec) at the same time. I am partial to the zero
crossing scheme. But then again, maybe that is because I am an analog
guy.

Wow - that's beyond my level!

If you use a DSP it isn't really rocket science. But the trick will be,
as with the 1KHz method, to treat the signal with silk gloves.

Another idea: Why don't you do all that at the RF level? Fire up the
transmitter, gently modulate it with something unique, wait until
stabilized, then close an RF gate with good isolation and synchronized
to the RF signal.

Now the receiver would measure the exact arrival of the RF and also
verify the unique modulation, to avoid triggering on a foreign signal.
Measuring zero crossings increases in precision as the frequency
increases. Just look at the frequency: At, say, 200MHz there are already
10 cycles in a 50nsec period. A simple threshold comparator circuit
could already achieve a timing accuracy far beyond of what you need. Of
course you'd have to know the group delay of all the filters in the path
up to this comparator. The wider the bandwidth of your total path the
lesser the effect of group delays.

Regards, Joerg

http://www.analogconsultants.com

 

[Electric dabbler]

"Scarfie" <chris@csmediapro.com> wrote in message
news:Xns9579708BC8676csmediaprocom@216.168.3.44...

Rich Grise <null@example.net> wrote in news:bcm8d.4327$cd1.143@trnddc03:

On Monday 04 October 2004 12:17 pm, Scarfie did deign to grace us with
the following:

Rich Grise <null@example.net> wrote in
news:QDg8d.5204$x65.3923@trnddc06:


Well, I have no idea how a DVD works, but if it's a data storage
medium, the data can be got out any way you want it, depending how
much hacking you want to do.

First, I need to drag my headbone into the 21st century - isn't a DVD
pretty much just a CD with an order of magnitude or so more storage?

Thanks,
Rich



Pretty much the same as CD. The only problem with getting the data out
the
way we want it is hacking into the deck's OS or hardware to make it do
what
it needs to do.

The system clock...the system clock...just need to override it with
another
clock signal...

Hi,

Sadly this wont be so easy on a DVD player, with CD players it IS possible
to alter the system clock and to some extent alter the
pitch of the audio since the data is clocked off the disc at the same rate
everything is locked to one crystal. So long as the frequency
change wasn't that much the CD player could continue to work just at the
wrong speed!

DVD players also have a master clock, usually about 27MHz (for the PAL
system), the problem is that altering this will alter all the timing in
the player, since the DVD player has to produce a correctly synchronised TV
picture the timing pulses for this will change too...

What you require is almost certainly possible, you would need to find a way
to modify the way the MPEG decoder behaves so that it repeats
frames many times until you are ready for the next one, thereby creating a
slow motion effect. Of course the servo would need to be controlled
also to keep the read buffer topped up . If you can find a consumer DVD
player that uses a chipset that is documented by the semiconductor
manufacturer
it might just be possible but quite extensive knowledge of programming would
be required.

Another option might be to use a DVD player that is based around a PC
DVD-ROM drive, these were quite common in the early days of DVD, it might be
possible to modify the control data going to the IDE interface so that
frames are repeated, I suspect that the MPEG decoder would get upset about
this
simplistic approach.

What about an 'industrial' DVD player with RS232 control?

http://www.colinbroad.com/cbsoft/manuals/p2DVD.pdf

Just a few thoughts,

Philip

 

[Spehro Pefhany]

On 5 Oct 2004 15:11:57 -0700, the renowned Winfield Hill
<Winfield_member@newsguy.com> wrote:

ChrisGibboGibson wrote...

Spehro Pefhany wrote:

Doesn't take much leakage across the capacitor or current source to
reduce the linearity at midscale down to the 12-bit level though.

I might have known you'd spot the flaw!

Some leakage, but dielectric absorption is usually more damaging.

It is reduced to an offset error when you do serial single-slope
conversion.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Spehro Pefhany]

On Tue, 05 Oct 2004 17:25:32 -0700, the renowned John Larkin
<jjlarkin@highSNIPlandTHIStechPLEASEnology.com> wrote:

On Tue, 05 Oct 2004 19:25:21 -0400, Spehro Pefhany
speffSNIP@interlogDOTyou.knowwhat> wrote:

On 5 Oct 2004 15:11:57 -0700, the renowned Winfield Hill
Winfield_member@newsguy.com> wrote:

ChrisGibboGibson wrote...

Spehro Pefhany wrote:

Doesn't take much leakage across the capacitor or current source to
reduce the linearity at midscale down to the 12-bit level though.

I might have known you'd spot the flaw!

Some leakage, but dielectric absorption is usually more damaging.

It is reduced to an offset error when you do serial single-slope
conversion.



Is it? The DA model is additional series R-C circuits across the main
cap. If the time constants are longer than the ramp time, that
obviously reduces to a shunt resistor, so will curve the ramp down.
The parasitic tau would have to be much shorter than the ramp time to
not bow the ramp, in which case it's just a small shunt cap, so is
basicly invisible.

ESR would cause a DC offset.

Does that make sense?

Yes, it does. A similar claim was in the National AN, and I don't
think it can be accurate.

Bob Pease says a 1uF Polyester cap (which has pretty high DA, of
course) looks (to a first order) as it has a 1G in series with 6nF in
parallel. That time constant is 6 seconds. Higher order terms are
about one decade less in time constant each- like 200M/3nF, 40M/1.5nF,
5M/1nF, 1M/800pF, 200K/600pF. So chances are there will be elements of
the DA that are both larger and smaller than the ramp time in time
constant.

Does anybody know what sorts of DA amplitudes and taus we might see on
a 0.1 uF ceramic cap? Or what sorts of c/v effects?
John

Here's some coarse info from a film capacitor maker:
http://www.wima.com/absorption.htm


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[xray]

On Tue, 05 Oct 2004 17:08:26 GMT, "Clarence" <no@No.com> wrote:

I usually do not see Fred's crap. Killfiled you know. SO your reply is the
first I have seen. He hasn't changed his song, nor got a clue.
Fred Boggs is FOS. The Polls show it "TOO CLOSE TO CALL" at this point.
He is simply trying, unsuccessfully, to show Bush being Bushwhacked by the
extreme left. It hasn't happened!

If your considering moving, pack your bags.

Thanks for popping in with more useless drivel. I haven't played here
much, and won't. Just let me say that you are number two on my list of
useless bull' spreaders. PD is number one.

 

[xray]

On 5 Oct 2004 10:30:43 -0700, jdurban@vorel.com (Product developer)
wrote:

In the end common sense will prevail

I certainly hope so. Your level of brainwashed crap has set new levels
of documented stupidity in this newsgroup.

 

[xray]

On 5 Oct 2004 17:57:22 -0700, soar2morrow@yahoo.com (Tom Seim) wrote:

They can move to the same country that Alec Baldwin moved to after
making the same threat in 2000. I would happily send them brochures.

Toughen up. You are only #3 in the list of right wing clowns here.

 

[xray]

On Wed, 06 Oct 2004 03:00:23 GMT, xray <notreally@hotmail.invalid>
wrote:

If your considering moving, pack your bags.

Oh, and I forgot to criticize you're grammar.

 

[George W]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:s4F8d.24567$QJ3.18364@newssvr21.news.prodigy.com...

Hi George,

<BIG snip>

Another idea: Why don't you do all that at the RF level? Fire up the
transmitter, gently modulate it with something unique, wait until
stabilized, then close an RF gate with good isolation and synchronized
to the RF signal.

OK, if the receiver has a DSP up front at the VHF input and the transmit
carrier is gated on cleanly at the source after it stabilizes then we should
be able to tell within a few RF cycles when the carrier arrives if S/N is
reasonable.

Now the receiver would measure the exact arrival of the RF and also
verify the unique modulation, to avoid triggering on a foreign signal.
Measuring zero crossings increases in precision as the frequency
increases. Just look at the frequency: At, say, 200MHz there are already
10 cycles in a 50nsec period. A simple threshold comparator circuit
could already achieve a timing accuracy far beyond of what you need.

Now I remember. About 10 years ago my company developed a satellite modem
using a DSP to do PLL threshold-extended FM demodulation. (We would need
just a simple discriminator in the present application.) I don't remember
whether the DSP was at the 70 MHz input or at a lower frequency after a
mixer. It might have been at 10.7 MHz I think.

It's been a few years since I looked at prices, but DSPs capable of 200 MHz
operation were pretty pricey then and they may still be. May reduce battery
life too. Attractive, though, because they can do a lot in addition to
serving as the FM demodulator. If too expensive at VHF one could be
mplemented after a mixer stage but then you have to pay for the mixer,
filter etc in addition to the DSP and it starts to lose it advantages for
counting RF cycles accurately as the frequency goes lower. Hmmmm ....

George

 

[Mike Monett]

Winfield Hill wrote:

Mike Monett wrote...

ChrisGibboGibson wrote:

John Larkin wrote:

[snip]

Comparing the results with a 10 digit meter I got accuracy
within 0.005% of the Vrefs I was using. That's quite amazing
for a dollars worth of comparator and discretes.

10 digit DVM? Who makes that?

Keithley, circa early 80s

Really? 6.5 and 7.6 or even 8.5 digits, but 10 digits?

Note, 6.5 or 7.5 digits lets one measure to better than 1ppm
resolution, yet 0.005% is only 50ppm, or 5.5-digit territory.

--
Thanks,
- Win

Chris is perhaps a bit confused. I believe the best dvm technology
available in the 80's was 6.5 digits, such as in the HP3456A, etc.

10 digits is, of course, 0.1 ppb. There was no way to calibrate a dvm to
this level prior to 1987, when the Josephson junction became the NIST
voltage reference. So a hypothetical 1980's 10-digit dvm could not even
be calibrated during the design cycle.

Also, if 10-digit dvm's were available in the 80's, we should be able to
purchase them now from used equipment vendors, such as John Bau: (A very
nice guy - if you need equipment, I recommend him highly)

http://www.users.qwest.net/~jbau/tstequip.htm

But he doesn't stock any. So a 10-digit dvm was not available in the
80's, and 8.5 digits is probably the best most of us will see.

Besides, what would anyone do with a 10-digit dvm? The thermoelectric
voltages would ruin any measurements we would likely make

Mike Monett

 

[budgie]

On 5 Oct 2004 05:19:04 -0700, johankarremans@hotmail.com (Johan Karremans)
wrote:

Can somebody tell me what the substitute ic is from ic 74LS173.

74LS173 in stock at my local supplier here in Perth Oz at $A0.99. Why do you
think you need a substitute - if I can get them down the corner, I'd be surpised
if they aren't available almost everywhere.

 

[Spehro Pefhany]

On Tue, 05 Oct 2004 23:40:29 -0400, the renowned Mike Monett
<no@spam.com> wrote:

Besides, what would anyone do with a 10-digit dvm? The thermoelectric
voltages would ruin any measurements we would likely make

Mike Monett

XXX.XXX XXX X volts is 10 digits. (up to 1000V and down to 100nV
resolution). Just not all 10 at once. ;-)


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Mike Monett]

Mike Monett wrote:

[...]

10 digits is, of course, 0.1 ppb. There was no way to calibrate a dvm to
this level prior to 1987, when the Josephson junction became the NIST
voltage reference. So a hypothetical 1980's 10-digit dvm could not even
be calibrated during the design cycle.

Update: NBS started using the Josephson junction in 1972, but the early units
had outputs in the low millivolts which required multiplying and scaling, and
gave an uncertainty of about 1e-8. 1V arrays became available in 1985, and 12V
by 1989. The Josephson constant became the legal standard for the volt on
January 1, 1990. For more info, see

"A Practical Josephson Voltage Standard at One Volt":
http://nvl.nist.gov/pub/nistpubs/sp958-lide/html/315-318.html

Even today, the best calibration service NIST offers is 40 ppb, and only by
special arrangement:

http://ts.nist.gov/ts/htdocs/230/233/calibrations/Electromagnetic/Voltage.htm

Mike Monett

 

[Robert Morein]

"martin griffith" <martingriffith@yahoo.co.uk> wrote in message
news:70q4m0lv8hi7ck1dskekjofrm5u8mtsri6@4ax.com...

On Tue, 5 Oct 2004 00:32:56 -0400, in sci.electronics.design you
wrote:

I like to watch movies with my laptop in my lap.
From what I've read about lithiums, this could be dangerous.
However, the only lithium accidents I've heard about involve cellphone
lithium polymers in plastic bags, presumably counterfeited in China.

Most laptops, on the other hand, use high grade Sony 16550 or 16850
cylindrical cells, which are hermetically sealed with conventional
organic
liquid electrolyte. In terms of robustness and longevity, this particular
design is considered to be the Cadillac of lithiums.

Is anyone familiar with, or has anyone heard of, incidents when this type
of
cell ruptured with explosive force, or enough heat to burn through the
pack
casing?

One manufacturing criteria the cell is supposed to withstand is sawing
through, or crushing the case, without provoking an explosion.

try this


http://www.eet.com/article/printableArticle.jhtml?articleID=47900158&url_prefix=issue/fp&sub_taxonomyID=


martin

The problem with counterfeiting is well known.
I buy my batteries from a distributor who obtain directly from Compal's U.S.
subsidiary.
The question is whether genuine lithium packs present a significant risk to
the user.