Radio clock signal7/30/2023 ![]() SIMON: Isn't that all taken care of on the Internet these days? I mean, we set the time according to what we see on our iPhones. So if the WWVB signal goes away, these devices will have to be changed manually. WITHERSPOON: Well, these little WWVB receivers are embedded in lots of devices that look for accurate timing - clocks, watches, weather stations, even irrigation systems. SIMON: So what would the effect of the closing of WWV be? THOMAS WITHERSPOON: Oh, thank you very much. Thomas Witherspoon wrote about this on his shortwave listener website, He joins us from the studios of the CBC in Quebec City - that's a lot of alphabet soup to get through in this intro. But a 2019 budget proposal for NIST would close WWV, WWVH in Hawaii and WWVB, which syncs up the time for about 50 million radio-controlled clocks, wristwatches and appliances. The time stamp is regulated by an atomic clock. It's signal provides a frequency standard for receivers. SIMON: WWV is the oldest continuously operating radio station in the United States. UNIDENTIFIED PERSON: National Institute of Standards and Technology time - this is radio station WWV, Fort Collins, Colo. For the digitizerNETBOX the time information of the host PC is used as the driver is running there.Shortwave listeners might recognize this signature ID. Please note that it is necessary to use the same source as time synchronization to the PC as the driver stores the starting time using the time information of the PC. MI series: timestamp module with extra connection needed.MC series: timestamp module with extra connection needed.M2i series: separate option BASEXIO or BASEXIO2 is needed as shown in picture.M3i series: connection through the extra I/O lines connector on front plate.M4x series: connection through the extra I/O lines connector on front plate.M4i series: connection through the extra I/O lines connector on front plate.M2p series: connection through the extra I/O lines connector on front plate.generatorNETBOX series: connection through connector on front plate.digitizerNETBOX series: connection through connector on front plate.The timestamp reference signal is connected to the Spectrum digitizer in different ways depending on the card family you're using: The right hand picture (click to enlarge) shows the setup for a M2i.2030 200 MS/s digitizer in combination with an IRIG-B receiver card. This timing signal can be taken from a GPS receiver, a radio clock or an IRIG-B receiver. The timestamp reference clock signal is normally a simple TTL signal that has a timing of one 1 Hz (1 pulse per second). This information can be used to synchronize acquisitions that have been done on different locations (like power line failures spread across the country) or the acquisition can be taken into relation to external events. The timestamp counter is split into two parts then, the lower part using the sampling clock as before and the upper part of the counter using the external reference signal as counting pulse (please see picture to the right, click to enlarge).Ĭombining the information of acquisition starting time (stored by the driver), reference clock signal count and timestamp sampling clock count, one gets a very precise absolute time information when the trigger signal has been received. One mode, called timestamp reference clock mode, uses an external signal to synchronize to. ![]() The timestamp of the Spectrum digitizers can run in different counting modes. If a trigger is recognized and an acquisition takes place, this timestamp counter is stored into a separate memory and can be read out afterwards. ![]() For this an internal timestamp counter is running permanently, driven by the sampling clock. ![]() The timestamp mode is used to get precise timing information of the received trigger signal. Using an IRIG-B, GPS or radio clock source as reference signal for timestamps Timestamp Theory ![]()
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