Hi
On a traditional RPi, many things go over the USB. The ethernet interface
connects via USB. On some, the WiFi also connects over USB. It all necks
down into a very narrow “pipe”.
Bob
> On Dec 5, 2019, at 3:21 PM, Anton Strydom wrote:
>
> HI Bob
>
> I do not require timing on the USB at
Hi
If you are moving blocks of data ( = pictures / video ) out over the same basic
USB interface. I suspect you will get into blocking issues. That sort of thing
will
make the basic “frame rate” stuff a bit less important. I have that same
“gotcha”
in what I’m doing. The network will be a bit
HI Bob
I do not require timing on the USB at all
On Thu, Dec 5, 2019 at 6:00 PM Bob kb8tq wrote:
> Hi
>
> One timing issue could be that USB is not that great for timing. Since it
> is
> packet based it introduces jitter in the link. Running NTP on a
> “traditional”
> RPi is unlikely to
>I'd like to test with the Raspberry Pi 4B which avoids USB in its gigabit
>Ethernet port path.
>
>Cheers,
>David
As a network engineer at a university I can tell you that you are just trading
one set of unknowns for a different and possibly larger set.
When you go from "n devices on the same
On 12/5/19 5:16 AM, Bob kb8tq wrote:
Hi
One timing issue could be that USB is not that great for timing. Since it is
packet based it introduces jitter in the link. Running NTP on a “traditional”
RPi is unlikely to produce numbers below a milisecond.
USB only guarantees 125 microsecond timing
Hi
Yikes
That should read “expected on an OCXO” !!!
Sorry !!!
Bob
> On Dec 5, 2019, at 8:05 AM, Bob kb8tq wrote:
>
> Hi
>
> That’s unexpected on an OCXO that may have been power off for a
> decade or more. Let it run for a month and see how it’s doing then.
>
> Bob
>
>> On Dec 2,
On Mon, Dec 02, 2019 at 12:30:44PM -0700, AC0XU (Jim) wrote:
> I have a FPS 1150A quartz oscillator with the 1 PPS disciplining
> option. With the frequency control set to "manual" I can use the digital
> thumbwheel control to set 10 MHz correctly. However, for two weeks there
> has been a
From: Bob kb8tq
Hi
One timing issue could be that USB is not that great for timing. Since it is
packet based it introduces jitter in the link. Running NTP on a
“traditional”
RPi is unlikely to produce numbers below a milisecond.
Indeed I’m digging into that for what I’m working on …..
Bob
Hi
One timing issue could be that USB is not that great for timing. Since it is
packet based it introduces jitter in the link. Running NTP on a “traditional”
RPi is unlikely to produce numbers below a milisecond.
Indeed I’m digging into that for what I’m working on …..
Bob
> On Dec 5, 2019,
Ok, thanks for the info. My unit should be arriving today or tomorrow.
--
David VanHorn
Lead Hardware Engineer
Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO 80301 USA
phone: 303-417-1345 x110
email: david.vanh...@backcountryaccess.com
-Original Message-
From: Scott
Hi
Since the DAC / reference is the main source of error, placing the sensor
a bit away from the OCXO makes sense. You also don’t want to watch the
OCXO heat the board. You want data on the outside temperature.
Since it’s all buried away in a Khalman filter, even the people who designed
it
Hi
That’s unexpected on an OCXO that may have been power off for a
decade or more. Let it run for a month and see how it’s doing then.
Bob
> On Dec 2, 2019, at 2:30 PM, AC0XU (Jim) wrote:
>
> Time Gurus-
>
> I have a FPS 1150A quartz oscillator with the 1 PPS disciplining option. With
>
A problem with inline measurement is that a suitable sense resistance for
measuring runtime current (perhaps at a few hundred mA) is not sensitive
enough for standby current (uA), and if chosen as a useful value for
standby current it drops far too much voltage during full power running.
An
kb...@n1k.org said:
> However if the âbroadcastâ NTP approach was the method of choice, then a
> wake up and do it would work. for. the server.
One of the disadvantages of broadcast is that you don't know what the round
trip time is so you can't use that to filter out quirky cases.
If
Good day Hal
Thank you for your contribution
The physical setup is as follows, each Rp1 has 2 or more cameras attached
to it via a multiplexer or usb depending on the camera, there are a number
of V2 RPi and also a couple of USB cameras attached to some of the RPi's.
All the equipment is powered
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