7/22/2023 0 Comments Wwvb radio![]() ![]() The Opendigitalradio project (a project to establish broadcasting systems for digital audio broadcasting), or rather Matthias HB9EGM himself, has built a GPSDO:Īside from the uBlox LEA-M8F GPS receiver, reference clock + PPS generator module, there's barely anything on that board – a chip to regulate the supply voltage, and one to protect against ESD if one decides to solder on the USB debugging plug. You can find a lot of these modules on the surplus/used market – Trimble GPS comes to mind, for example – but you can also build such things yourself: Thus, in the professional world, WWVB and similar things are pretty much forgotten, since the signal simply is too narrowband to give you a good frequency and timing estimate within short time. GPS-discplined oscillators (GPSDOs) are really common in cellular base station technology, where you must very accurately coordinate frequency (and time), to be able to use the (billions of euros) licenses for the limited spectrum you've got most efficiently – avoid the guard band between you cell's "own" band and the neighboring cell, as well as minimize frequency-error induced losses in transmission. Frequency standards in cellular infrastructure You'll find a lot of modules on the market that will not only give you a Pulse Per Second (PPS), but also a frequency standard signal, most commonly 10 MHz, but there's other frequencies, too. The table includes periods when the signal was off or intermittent for more than 5 minutes.GPS-based frequency answer rightly pointed at devices that use GPS to generate the 1-second pulsing.Ĭuriously, these modules only address the once-per-second accuracy issue, not the frequency standard issue, which GPS is indeed commonly used to solve: Broadcast Outages for WWVB WWVB Homeĭuring normal operation, the 60 kHz signal from WWVB is transmitted 24 hours per day, 7 days a week. For more information, contact Broadcast Manager Michael Lombardi at michael.lombardi or (303) 497-3212. A detailed technical description of the new format can be found here.ĭisciplined oscillator products that track and lock to the 60 kHz WWVB carrier and were designed to work as frequency standards, will not work with the PM signal and will now become obsolete. A few radio controlled clocks that used information from the carrier – specifically the Spectracom NetClock and receivers manufactured by True Time during the 1970s and 1980s – will no longer be able to read the time code and will also be obsolete. Existing radio-controlled clocks and watches are not affected by this enhancement, and continue to work as before. This enhancement to the broadcast, which has been tested throughout 2012, provides significantly improved performance in new products that are designed to receive it. Since Octoat 1500 UTC (9:00 AM MDT), NIST Radio Station WWVB has been broadcasting a phase modulation (PM) time code protocol that has been added to the legacy AM/pulse-width-modulation signal. ![]()
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