[Context is filtering on inputs from switches.]
Could somebody tell me why we are doing anything fancy at all? What's wrong
with just a simple pullup?
I can think of two cases that might be interesting.
One is signal integrity. There might be enough crosstalk to cause troubles.
This is a
Hal Murray wrote:
[Context is filtering on inputs from switches.]
Could somebody tell me why we are doing anything fancy at all? What's wrong
with just a simple pullup?
Pull down required because of thumbwheel switch encoding.
I can think of two cases that might be interesting.
One
Magnus is on vacation and has some (net) connectivity problems. I would
expect him to be back online within a day or two.
--
Björn
On Wed, 2008-07-16 at 18:27 +0100, David C. Partridge wrote:
I'm waiting to see what Magnus Danielson has to say, as it was he after all
who suggested adding
David C. Partridge wrote:
I'm waiting to see what Magnus Danielson has to say, as it was he after all
who suggested adding caps in parallel to the pull-downs, and also series
resistors.
Thinking about it retrospect, I think he may have meant the series resistors
to go between the pull-downs
of precise time and frequency measurement'
Subject: Re: [time-nuts] Frequency divider design critique request
Magnus,
Was the attached what you had in mind?
Thanks
Dave
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-- john, KE5FX
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of David C. Partridge
Sent: Tuesday, July 15, 2008 11:07 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Frequency divider design critique request
John
John Miles wrote:
Right; when the thumbswitches are toggled, the RC integrators will slow down
the edges into pins 9-11. Sometimes CMOS parts will latch up or otherwise
fail to reliably with slow edges -- it probably comes down to the
complementary thing, where both halves of a totem pole can
John Miles wrote:
Right; when the thumbswitches are toggled, the RC integrators will slow down
the edges into pins 9-11. Sometimes CMOS parts will latch up or otherwise
fail to reliably with slow edges -- it probably comes down to the
complementary thing, where both halves of a totem pole can
John Miles wrote:
Right; when the thumbswitches are toggled, the RC integrators will slow down
the edges into pins 9-11. Sometimes CMOS parts will latch up or otherwise
fail to reliably with slow edges -- it probably comes down to the
complementary thing, where both halves of a totem pole can
From: Bruce Griffiths [EMAIL PROTECTED]
Subject: Re: [time-nuts] Frequency divider design critique request
Date: Sat, 12 Jul 2008 12:11:03 +1200
Message-ID: [EMAIL PROTECTED]
Magnus Danielson wrote:
Why not? It basically solves a problem most of us has, and only a few tweaks
away
Magnus
Magnus
A minimalist approach for the 5MHz to 10MHz doubler could use a full
wave (diode, BJT or JFET) doubler followed by a series tuned 5MHz
shunt trap to minimise the 5MHz content in the output.
Actually, it depends on weither you would like to get a 10 MHz or not.
Another
Bruce Griffiths wrote:
I was only thinking that maybe there ought to be a buffer from the input
to the rectifier, or else higher frequency energy will escape out
towards the
source. At least some isolation should be there.
If one uses a common base stage to drive the diode
There are usually some BNC bulkhead connectors on eBay that terminate
in SMA/SMB/SMC pigtails, which are great for panel mounting.
Not directly related to this design, but it made me wonder about something.
If you are building a multiple output system and channel phase to channel phase
was
Bob Paddock wrote:
There are usually some BNC bulkhead connectors on eBay that terminate
in SMA/SMB/SMC pigtails, which are great for panel mounting.
Not directly related to this design, but it made me wonder about something.
If you are building a multiple output system and channel
Magnus Danielson:
1) Please could you clarify what you're proposing with the series resistors?
I get the idea about 10nF in parallel with R24-R26, though I'm not sure what
the benefit is? Those MUX control pins are going to sit pretty hard on 5V
or pulled down to ground.
2) You said:
I am
From: David C. Partridge [EMAIL PROTECTED]
Subject: Re: [time-nuts] Frequency divider design critique request
Date: Fri, 11 Jul 2008 18:41:52 +0100
Message-ID: [EMAIL PROTECTED]
Hej David,
Magnus Danielson:
1) Please could you clarify what you're proposing with the series resistors?
I get
At 10:41 AM 7/11/2008, David C. Partridge wrote:
M
All,
CPLD - wassat? OK, OK I have some idea, but that's about all I know.
Anyway these are probably BGA stuff which I couldn't hope to hand solder
anyway - it's enough of a stretch for me to think of hand soldering this SMT
board.
CPLD - small
Jim Lux wrote:
At 10:41 AM 7/11/2008, David C. Partridge wrote:
M
All,
CPLD - wassat? OK, OK I have some idea, but that's about all I know.
Anyway these are probably BGA stuff which I couldn't hope to hand solder
anyway - it's enough of a stretch for me to think of hand soldering this SMT
Magnus Danielson wrote:
Hej David,
Magnus Danielson:
1) Please could you clarify what you're proposing with the series resistors?
I get the idea about 10nF in parallel with R24-R26, though I'm not sure what
the benefit is? Those MUX control pins are going to sit pretty hard on 5V
or
Magnus
A minimalist approach for the 5MHz to 10MHz doubler could use a full
wave (diode, BJT or JFET) doubler followed by a series tuned 5MHz shunt
trap to minimise the 5MHz content in the output.
If the doubler components were perfectly matched (unlikely) the
fundamental trap could be
David Partridge wrote:
CPLD - wassat? OK, OK I have some idea, but that's about all I know.
Anyway these are probably BGA stuff which I couldn't hope to hand solder
anyway
Many CPLD's are leaded. Only the high-pin count CPLD/FPGA's are BGA.
Chris Hoover,
Christopher, per favor.
You
In my best HAL 9000 voice;
Hi Dave. Dave, what are you doing ? Dave we need BNC connectors. Those SMB's
are hard to work with. Dave, are you intending to have those SMB's stick out
through a panel ? Dave ? Dave, let me suggest that you layout the connector
pattern so either one can be used
I am not a big fan of BNC connectors on the PC board itself, because I am
not a big fan of attaching PC boards directly to panels in most cases.
There are usually some BNC bulkhead connectors on eBay that terminate in
SMA/SMB/SMC pigtails, which are great for panel mounting.
From: David C. Partridge [EMAIL PROTECTED]
Subject: [time-nuts] Frequency divider design critique request
Date: Thu, 10 Jul 2008 21:30:56 +0100
Message-ID: [EMAIL PROTECTED]
David,
As I've mentioned before, I've been working on the design of a frequency
divider to go with my TB.
The idea is
Hej Magnus
Magnus Danielson wrote:
David,
As I've mentioned before, I've been working on the design of a frequency
divider to go with my TB.
The idea is 10MHz sine in from TB, output 2.5Vp-p 50% duty cycle square wave
into 50R (5V into 1M), at 10Mhz, 5MHz, 1MHz and decade selectable
Hi David,
It looks like your design is pretty far along, so maybe it's too late for this
suggestion, but one thing you might consider is replacing the 7400 series logic
with a 5V CPLD programmable logic device.
This could offer several advantages:
1) any issues (such as jitter) could be
[EMAIL PROTECTED] wrote:
Hi David,
It looks like your design is pretty far along, so maybe it's too late for
this suggestion, but one thing you might consider is replacing the 7400
series logic with a 5V CPLD programmable logic device.
This could offer several advantages:
1) any issues
Magnus Danielson wrote:
I would consider a dedicated 1 PPS output.
I would consider a synchronise feature with a PPS/synchronise input. It should
be wise to not directly wire it to the counter resets, but provide an arm
button and maybe a very simple arrangement to indicate left, on mark and
The CPLD's (unlike the FPGAs) are single chip solutions.
There are many single chip FPGA solutions today from several different
companies.
If you are in the US and near a Avnet office you can pick up a Actel
Igloo Icicle
eval. board/programmer for $49. They are giving them out at the Actel
On Fri, Jul 11, 2008 at 11:33:53AM +1200, Bruce Griffiths wrote:
[EMAIL PROTECTED] wrote:
Hi David,
It looks like your design is pretty far along, so maybe it's too late for
this suggestion, but one thing you might consider is replacing the 7400
series logic with a 5V CPLD
The TrueTime XL-AK Time Frequency Receiver does just what you want plus
a few more outputs. Unfortunately they do not provide schematics in the
manual.
73, Dick, W1KSZ
-Original Message-
From: David C. Partridge [EMAIL PROTECTED]
Sent: Jul 10, 2008 1:30 PM
To: 'Discussion of precise
John Miles wrote:
I am not a big fan of BNC connectors on the PC board itself, because I
am not a big fan of attaching PC boards directly to panels in most cases.
There are usually some BNC bulkhead connectors on eBay that terminate
in SMA/SMB/SMC pigtails, which are great for panel
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