Time issue ,

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Steve Shuff

Aug 21, 2021, 8:50:58 AM8/21/21
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Hi All
I am trying to get to the bottom of a timing related issue.

As you can see below is a clip from my Wave_Server  (via sniffwave)

 WBK.HHE.GB.00 (0x0 0x0) 0 i4  75  75.0 2021/08/21 12:29:40.00 (1629548980.0000) 2021/08/21 12:29:40.99 (1629548980.9867) i255 m143 t19 len 364 [D:1.66s F: 1.0s]
The content  " [D:1.66s F: 1.0s] " from above  means what ?
I am thinking that the D and F relate to Delay and Fast  but I would like to know for sure please.
The EW version is the most current running on a Raspberry Pi 3B+ of which when when checking the time against the "Time is" internet function shows only to be 0.025 sec of error..
The WFTimefilter log shows 
20210821_UTC_12:14:37 WBK.HHZ.GB.00 1629548075.000 1.000 s overlap detected; rejecting out-of-sequence packet (starttime 1629548074.000)

 The Digitizer is an EarthData PS2400 with GPS which does suffer the WRNO ,
However ElBerto from the forum kindly wrote the EW module for the PS2400 with a WRNO fix included.

Any help would be appreciated . 

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Baker, Lawrence M

Aug 21, 2021, 12:26:50 PM8/21/21
to steves...@gmail.com, Baker, Lawrence M, 'Meremonte, Mark E' via Earthworm Community Forum

Type sniffwave with no arguments and you'll get something like this that explains what D ans F mean:

$ sniffwave
sniffwave version 2016-11-16 2.5.6
Usage: sniffwave <ring name> [sta] [comp] [net] [loc] [y/n/s/time] [v]
 Note: All parameters are positional, and all but first are optional.
 Appending the optional 'v' or 'verbose' argument causes module,
 installation and type names to be printed in addition to usual ID numbers.
 The <y/n/s> flag is a data flag or 'time in seconds'. If 'y' is specified
 the full data contained in the packet is printed out.
 If flag set to s, provides max/min/avg statistics of the trace data.
 If flag set to numeric value, program runs only for that number of seconds.
 If sta comp net (but not loc) are specified then only TraceBuf
 packets will be fetched (not TraceBuf2); otherwise both are fetched.
 sniffwave output Data and Feed latencies in this form [D: secs F: secs]
 Data latency is the difference between current time and last sample time in current packet.
 Feed latency is the difference between current time and previous packet arrival time.
 Example: sniffwave WAVE_RING PHOB wild NC wild n
 Example: sniffwave WAVE_RING wild wild wild y verbose
 MSEED capability starting with version 2.5.1, prints mseed headers
 of TYPE_MSEED packets (no filtering yet).

Larry Baker
US Geological Survey

On Aug 21 2021, at 5:50:46 AM, Steve Shuff <steves...@gmail.com> wrote:


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El Berto

Aug 23, 2021, 3:14:09 AM8/23/21
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F value is correct due to Earthdata protocol: 2400 provides data in 1 second packet so to receive data you need to wait about 1 second to fill block.

Steve Shuff

Aug 23, 2021, 4:23:49 AM8/23/21
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Thanks for your reply which makes sense now.
I was curious, as sometimes the system would run for 90 minutes without any time warnings then some would show before returning to no errors again.
My first thought was it may be a GPS issue not seeing the whole sky as where it is located there are trees covering approx 50 % of the sky .

On another note, how much work would be involved in compiling a module for the SARA SADC1.0 digitizer ?
There was a module developed for Windows but not for the Raspberry Pi, Thought I might try to develop the Pi version if it's not too difficult 

Best regards 

Steve Shuff.

El Berto

Aug 23, 2021, 12:25:57 PM8/23/21
to Earthworm Community Forum
Internal PLL should keep clock, if not clock would drift but it should do it enought slowly.
I don't remember if ED protocol would manage satellites number...

About Sara I don't know, I started writing ED module from ED serial protocol, you should get Sara protocol (I hope serial) or make reverse-engineering of Windows software source code but it will take much more time.
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