Gps receiver with 1pps output
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All of our Distribution Amplifiers are built in the U.One approach would be to synchronize a fixed frequency oscillator on the leading edge of the 1PPS signal. In many cases, this will result in adequate performance.
However, in situations where simple synchronization does not provide adequate performance, digital phase-lock techniques can be applied to a digital oscillator to achieve much better results. This article will describe a DPLL that locks a digital oscillator, i.
Increase Pulse Width 1 PPS signal from GPSDO
Furthermore, the DPLL will smoothly re-lock to the external timing reference when it is restored. This article will not provide an in-depth review of phase-lock techniques. The Web has many excellent articles on the subject.
Readers not familiar with phase-lock techniques are encouraged to read his article: Discrete-time PLLs, Part 1: Basics. In my work, I need to be able to operate equipment in such a manner that it is aligned to an external timing reference such as the GPS 1PPS signal. This requirement is generally associated with a requirement to provide time tags for measurements of events in a consistent manner even when the equipment is distributed on a network.
The resolution required of the time tags that accompany the measurements is generally such that normal time synchronization methods, such as Network Time Protocol NTPare inadequate for the purpose. Every oscillator made has a fundamental error: its absolute frequency with respect to its specified operating frequency is non-zero.
Furthermore, even if its frequency was absolutely correct, its phase relative to another oscillator at the same frequency would not likely be the same. To reliably exchange data between two systems operating using different clocks, the frequencies have to be the same or there will exist a finite probability that the data will arrive within the meta-stability window of the receiver and be corrupted.
Even when the frequencies of the two oscillators are exactly equal, the phase of the two oscillators must be such that the receiver can sample the data outside its meta-stability window.
Time server using 1PPS GPS receiver
Phase-lock techniques allow one oscillator, a variable oscillator, to be frequency and phase aligned to another. Simple synchronization of one oscillator to another does not remove the frequency errors, and the resulting frequency errors that remain can cause the meta-stability issue discussed above unless the synchronization process occurs at a rate fast enough to keep the sampling window in the stable region between the two clock domains.
For example, the frequency differences that remain between two synchronized, but not phase-locked, systems is the reason that synchronization is performed for each character when using asynchronous communications devices such as UARTs.
In terms of time, the frequency difference between systems produces an effect that slews time between them. Depending on the desired time tag resolution and the period over which the measurements are made, the frequency difference that can be tolerated can be quite low. Using a DPLL, the frequency and phase differences between the systems can be reduced such that the remaining errors are proportional to the period of the reference oscillator of the digital oscillator, i.
DDS, being used. In fact, it is possible to measure the frequency of the reference oscillator relative to the external timing reference, and essentially eliminate time drifts between the two systems because the frequency error of the reference oscillator has been eliminated while the digital oscillator was being phase-locked to the external timing reference.
The diagram follows the form of the classic PLL with the exception of the limiter function following the phase detector PD. The red external signal input is processed in the OSC clock domain to avoid meta-stability issues.Welcome, Guest.
Please login or register. Did you miss your activation email? This topic This board Entire forum Google Bing. Print Search. Read times. I've looked at the Navman Jupiter-T but it's way out of budget. Gyro Super Contributor Posts: Country:.
It has two outputs which can be programmed anywhere up to several MHz though you have to be careful to get an integer divide of it's TCXO at MHz frequencies. I did some experements still need to box it! Chris "Victor Meldrew, the Crimson Avenger!
Thanks for the reference. Will have a read through that today. Much appreciated. GPS looks easier and more stable. Hope it helps. I had to use an analogue switch to float the loop filter during the absences. It did work, but was jittery as hell.
The alternative is DCF A high impedance buffer tapped onto the crystal might work but I've never tried it. It's also prone to interference - most radio controlled clocks work on the basis of getting a fix sometimes. Yes, GPS is definitely a better bet these days. Bryan Frequent Contributor Posts: Country:.
Quote from: SingedFingers on January 21,pm.
Quote from: Bryan on January 22,am. Thanks everyone. I wanted to avoid the PPS output as I'm impatient and it takes a shorter amount of time for the PLL to lock on a higher frequency signal from my slightly shoddy experiments with the 74hcMany ham radio operators use this as their 10 MHz reference for frequency locking radios. They come in two versions, one that is sine wave, the other a square wave so choose according to your application.
As a result, the designer has chosen to use a very long loop time constant — several thousand seconds at least. Initially it will be within 0. For optimum GPS signal Lock, place the antenna for a clear view of the sky, avoid potential interference sources such as high voltage power lines, etc. Q : I use a frequency counter and the frequency of the device shows a difference, what should I do? A : The LCD frequency of the device is from a internal calculation, the actual test frequency may have a deviation.
However, when the machine displays L A : Some of this is normal. The signal strength is affected by the satellite locations, weather rain, snow, etcand any signal absorption, or reflections. LCD Display Option Programming Commands currently are to be sent as a double basic string, without a space between them.
It is a freeware, portable app. Key Features 10 MHz low noise sine wave, high stability output. Inexpensive, compact, and user programmable options for the LCD display format.
Unique algorithm to maintain high accuracy 10 MHz Frequency Standard output. SIZE: H 55mm 2. External DC power, 5. User defined 6-character display area. Time Display; user options are available for international Time Zones. Highest Accuracy is when the least significant digits are 0. Q : The displayed GPS signal strength changes from high, to low, etc. Cookies on this site are used to personalize content and ads, to provide social networking features and analyze traffic.
We also share information about your use of the website with our partners social networking, advertising and web analytics who can combine it with other information provided to them or they have gathered from the use made of its services.Additional 1PPS and frequency outputs are available with option cards.
To configure these outputs, navigate to:. External 1PPS sources "references" —if present and valid—are utilized to discipline the oscillator, in other words to correct for oscillator drift the oscillator cannot discipline to either NTP input, or a User set time, unless in Host Disciplining mode. If no external 1PPS input references that can be used for disciplining are present, the oscillator will be in Freerun mode. The on-time point serves to accurately align the outputs, such as the 1PPS output, to the correct time, based on its reference inputs.
The on-time point of the 1PPS output can be configured to be either the rising or falling edge of the 1PPS signal by default, the rising edge is the on-time point. An Orolia Brand. SecureSync Online User Manual. Spectracom - Essential Ingenuity. You Are Here: You are here:.
All Files. Like other types of SecureSync 's signal outputs, a 1PPS output can be configured in several ways: Signature Control allows you to determine under which conditions an output signal shall be present, i. See also Signature Control. The on-time point of the 1PPS signal: rising or falling edge The pulse width An offset can be entered to account for cable delays or other latencies. Download PDF Manual. Follow us on Twitter. Follow us on LinkedIn. Follow us on YouTube.
Publishing Date: FebruaryWhat is a time server?
A time server gets its time from a reference time source. That source can be a another time server, a local time source such as a rubidium or cesium atomic clock.
Its longtime time drift is about 0 seconds. This is possible because the GPS time signals are constantly adjusted to keep very accurate time needed for navigation. This is not a project for a beginner.
I will generally describe what you need and assume you have a usable set electronics skill. Now let get all the important stuff you need:. A GPS receiver with an one pulse per second output. Mine is a UPB subtype. It has a backup battery connector for time keeping while no power is available. Choose a module which breaks out the DCD input and the 3. Mine is a breakout board made by HEX. You also need a prototype pcb to mount all the parts.
I used one which measures about 5x7cm. Get yourself a nice project box to put the pcb in.
Besides these components you will also need some tools like a soldering iron, screwdriver and drills. But I guess you already have them. When soldering all components on the pcb, you should connect all common signals together. For example, the 3. Same with all the GND connections. Capacitor C2 will be charged when power is applied and will provide the GPS module with some power to keep track of time when the USB connection is temporary disconnected. The LED flashes with every 1 pulse per second.
I used a blue LED. The UP gps module is very sensitive and worked about 2 meters away from a door which has no direct line of sight to the sky. Note that the antenna of the GPS module is the ceramic part and not the metal shielding. Keep in mind the orientation in such a way that the antenna can be pointed to the sky. I use a windows workstation to test the GPS module. Start your favorite serial terminal I used Putty and configure it for 8N1.GPSモジュールGM-316の1PPS出力
You should see something like this:. These are NMEA sentences and are outputted once per second. You now can use the module in your time server, but you can also reconfigure the defaults to output more GPS sentences and use a faster baudrate.
This program can change the default settings of your gps module.Please contact Microsemi for details. Configure and Get a Quote. The XLi SAASM is designed to generate precision time and frequency signals to synchronize high bandwidth mission critical communications systems that require the highest security support.
Classified Red keys are also supported. For example, the N. The XLi SAASM configuration recognition software automatically detects the unit''s setup at power-on providing "plug-and-play" configuration capability for current and future application needs.
MyMicrosemi Partner Portal. PoE Support Cases. PoE Collateral. Storage ICs Documents and Software. Timing ICs Documents. Overview Resources. Secures Military Communications The XLi SAASM is designed to generate precision time and frequency signals to synchronize high bandwidth mission critical communications systems that require the highest security support.
Field-ready The XLi SAASM configuration recognition software automatically detects the unit''s setup at power-on providing "plug-and-play" configuration capability for current and future application needs.