Kasper,
I am impressed a lot by the simplicity of your ideas. Added what Bruce
has said to it I think the idea can even be improved by
a) using a 12.288 MHz source for the micro.
and
b) using one (or two)external d-flip-flop(s)
The GCD of 1000 Hz and 12288000 Hz is 16000 instead of 3200
I've been working on the design for a frequency divider to complement the
Thunderbolt I recently bought from TVB (thank you Tom, it's working very
well as far as I can tell, though of course I've no other standard to
compare against).
Thanks to lots of advice and guidance from Bruce Griffiths
Randy,
10.238 MHz was very likely used for GPS applications. With GPS, it is
more important to keep LO harmonics away from the L1 input frequency
than to use any particular round frequency. The IF can be anything
suitable, as the baseband data is recovered using an NCO which corrects
for LO
Dave,
I do that sort of work for a living and a hobby. I'd be happy to
generate PC board artwork for you in exchange for one unit of the
finished product.
Perhaps you could post a schematic diagram, and I could evaluate it further.
Answers to your specific questions below.
At 7:19 PM +0100
Hi David and list
I am quite interested in this post too.
I have wanted to fabricate my own PCBs for several years now but I have
never made an attempt. I am set up here to do silk screening and I have
ovens and a hot-air soldering iron. Has anyone else tried to fabricate
their own boards or
David and Patrick,
Check out the following two sites to get an idea of the
current costs to have a custom made board produced.
http://www.pcb123.com/
http://www.expresspcb.com/index.htm
Richard
Hi David and list
I am quite interested in this post too.
I have wanted to fabricate my own PCBs
Hi,
I've had good experiences with www.pcbex.com. A little cheaper than
pcbfabexpress (which I've also used and recommend). Batchpcb (which someone
else mentioned) has been good for 1-off boards if they aren't too big --
sometimes
I've gotten boards which aren't sheared quite square, but
Hi David,
for guaranteed product quality, including choice of material (FR4 choices,
Getec, etc), tight impedance control, cleanliness (to reduce loss tangent
especially for high-frequency performance), and documentation including
solder-samples and cross-sections etc, try:
HI Dave,
for quick and inexpensive one-off designs, you may try a one-layer PCB.
Basically mounting all the parts onto an FR4 clad with Copper on one or two
sides (BTW: 5-layer boards don't exist as far as I know).
Use SMD parts, and bend-up the ground pins. Then solder these parts
Hi David:
1) There are many benefits of using Surface Mount Devices (SMD). In addition
to the reduction in board area just because the part is smaller there's also a
major reduction in board area because of the lack of through holes, i.e. you
get to use both sides of the board (doubling the
These are the ones we've used. I am sure there are many others.
Prototypes -- www.pcbfabexpress.com
Production -- www.pcbnet.com
Is there a way to split the layers of an old board apart to study them?
An assembly shop can x-ray them for you.
Also, as a group, dentists are bigger gadget
Prologix wrote:
David,
These are the ones we've used. I am sure there are many others.
Prototypes -- www.pcbfabexpress.com
Production -- www.pcbnet.com
Is there a way to split the layers of an old board apart to study them?
An assembly shop can x-ray them for you.
Regards,
Ulrich Bangert wrote:
Kasper,
I am impressed a lot by the simplicity of your ideas. Added what Bruce
has said to it I think the idea can even be improved by
a) using a 12.288 MHz source for the micro.
and
b) using one (or two)external d-flip-flop(s)
The GCD of 1000 Hz and 12288000
John Miles wrote:
For one-off PCBs, I've had good luck with www.batchpcb.com .
I agree. I've used them once and have been happy with the
results, you just can't be in any hurry. Unfortunately,
there's no indication of how long it will take a priori.
SMD is not hard to work with by hand,
At 08:04 PM 6/2/2008, you wrote:
Personally I *hate* turning boards over and clipping leads.
And I'd much rather layout SMD than T/H.
A man after my own heart. 0.5mm and even 0.4mm pin pitch is fine, QFN
is doable, but takes patience sadly BGA is a bit beyond the pale for
me right now until I
On Monday 02 June 2008 02:31:18 pm Patrick wrote:
I have wanted to fabricate my own PCBs for several years now but I have
never made an attempt. I am set up here to do silk screening and I have
ovens and a hot-air soldering iron. Has anyone else tried to fabricate
their own boards or is the
Quoth Bruce Griffiths at 2008-06-03 09:50...
How do you cope with SMT parts (eg high frequency ADCs) with metal
thermal transfer /ground connections under the package itself?
Haven't done it myself, but interested to hear others experiences. I'm
guessing that this would be a job for solder
Quoth Bob Paddock at 2008-06-03 10:04...
Cheapest place I've come across for easy boards with 10mil or large lines
is this one, but I've not used them yet (probably next month I will):
http://www.futurlec.com/PCBService.shtml
I was looking at these - they actually do overseas shipments for
On Monday 02 June 2008 04:53:17 pm [EMAIL PROTECTED] wrote:
Not the cheapest, but great for professional proto's when quality trumps
cost (above 1GHz, one source FR4 is totally different from another sources
FR4...)
Anyone have suggestions for Metal Core Protype Boards?
Used in high power
Bob Paddock wrote:
2. How many layers? In an ideal world with money no object, if I
understand the current art correctly, I think I'd probably aim for a five
layer
I assume that is a typo? You can not have an odd number of layers.
In this current 3D reality each layer has two sides.
How do you cope with SMT parts (eg high frequency ADCs) with metal
thermal transfer /ground connections under the package itself?
How to succeed the first time with ultra-small QFN packages
http://www.wirelessnetdesignline.com/showArticle.jhtml?articleID=202800018
A really good way to handle the pad on the bottom of the part is to put a
hole through the board right there. You usually need a bunch of vias to tie
the pad to the ground plane on the bottom of the board anyway. Put one hole
large enough for your soldering iron tip to reach in and touch the
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of David C. Partridge
Sent: Monday, June 02, 2008 1:20 PM
To: 'Discussion of precise time and frequency measurement'
Subject: [time-nuts] PCB design questions
I've been working on the design for a
I`m curious : What is a virgin teflon standoff, and does it have anything
to do with the teflon Don?
I don`t see much SMD, here, at the extreme edge of the known Universe, but I
can see that the single sided approach would make tracing a circuit much
easier,..
Quoth Bruce Griffiths at 2008-06-03 09:50...
How do you cope with SMT parts (eg high frequency ADCs) with metal
thermal transfer /ground connections under the package itself?
Haven't done it myself, but interested to hear others experiences. I'm
guessing that this would be a job for
Don Collie jnr wrote:
I`m curious : What is a virgin teflon standoff, and does it have anything
to do with the teflon Don?
...Don
C.
Don
In this context virgin teflon means machined from solid teflon and not
In message: [EMAIL PROTECTED]
Bruce Griffiths [EMAIL PROTECTED] writes:
: Don Collie jnr wrote:
: I`m curious : What is a virgin teflon standoff, and does it have anything
: to do with the teflon Don?
:
...Don
Another option is to cook the boards in a skillet.
http://www.sparkfun.com/commerce/present.php?p=Reflow%20Skillet
While John may be brave enough to hand solder BGA I am not :-)
Shorts can be easily detected with x-ray, but opens can be quite difficult
to spot.
If you do endup hand soldering
Prologix wrote:
Another option is to cook the boards in a skillet.
http://www.sparkfun.com/commerce/present.php?p=Reflow%20Skillet
While John may be brave enough to hand solder BGA I am not :-)
Shorts can be easily detected with x-ray, but opens can be quite difficult
to spot.
If you do
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