Tag Archives: Clock

8T49N004 Programmable Femtoclock® NG with 4-outputs

This design features a fourth generation programmable femtoclock that provides reference frequencies to replace crystals and SAW oscillators in high-performance applications. It is programmable through I2C interface. It has four selectable LVPECL or LVDS via I2C while its FemtoClock NG VCO ranges between 1.9GHz to 2.55GHz. It also meets the standard interface requirements of PCI Express (2.5Gb/s), Gen 2 (5Gb/s), and Gen 3 (8Gb/s) jitter that are low in both clock synthesizers and phase-locked oscillators.

The design is comprised of few components that can be divided into three main areas. First, the I2C interface area that uses optoisolator to ensure the compatibility of the external I2C device to the main clock frequency synthesizer. Second, the main part where the IDT8T49N004I clock generator generates the clock with selectable LVDS or LVPECL outputs. Lastly, the power supply of the device uses a low noise Low DropOut (LDO) regulator that is optimized for fast transient response. It also makes use of reference diodes and capacitor filters that secure the system from possible noise produced from the supply.

The design is applicable to several applications that requires reference clock especially network processors and Application-Specific Integrated Circuits (ASICs). It can improve the overall performance of the device since it makes the device more immune to noise and other undesired system behavior.

8T49N004 Programmable Femtoclock® NG with 4-outputs – [Link]

Nixie Tube Clock

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by Pete Mills :

If you’ve poked around the internets where electronics hobbyists collect, it is likely that you are acutely aware of our incontrovertible affinity for building timekeeping clocks. It is similarly unlikely that you have been able to evade the plenitude of nixie tube based projects. There is a reason for this.

Nixie tubes are cool. They have great aesthetic appeal with their difficult-to-photograph, warm orange glow, and dem curvy numerals. They add an organic je ne sais quoi to a hobby with ostensibly digital design cues. Further, they pose technical challenges in the way of producing and switching the ~175 V DC needed to light each tube element. And as far as I am aware, there are no new nixie tubes being produced; as such, procurement can be a challenge unto itself. My N.O.S. nixies came from Russia thru Ebay, and only 3 were duds. Incidentally the seller replaced those 3, FOC.

Nixie Tube Clock – [Link]

Arduino DCF77 Master Wall Clock

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by oliverb @ instructables.com:

Time displayed on large 1″ (26mm) 7 segment displays with secondary 4×20 LCD information display. The clock can be used stand alone or provides the following pulses to drive slave clocks 1 sec alternating, 30 sec, 1 min , 1 hour, 24 hr, 15 min chime of quarter hours, hourly chime of hours.

An Arduino 328 Microprocessor is used to decode and display time & date from the DCF77 “Atomic” Clock in Mainflingen near Frankfurt Germany.
The DCF77 signal is decoded using the fantastic new DCF77 library written by Udo Klein meaning the clock stays in sync and keeps perfect time even with a massive amount of noise on the received DCF77 signal. Udo Klein’s DCF77 library also continually “Auto Tunes” the quartz crystal so in the rare event the signal can’t be decoded the clock remains accurate within 1 sec over many days.

Arduino DCF77 Master Wall Clock – [Link]

Arduino VFD Display Clock Tutorial

FP770N2IBL0P092.MEDIUM

by Kesselwagen @ instructables.com

Vacuum fluorescent displays look really kinda fancy and cool to me, I really love the blue-breen color. That’s why I decided to write this Instructable about a clock based on this technology. This is my first instructable here, showing you how I have designed built my clock and how you can build yourself exactly the same or a similar clock that utilizes the VFD display. I’m not a native speaker – just for you to know if you’re wondering why some sentences might make no sense at all.

Arduino VFD Display Clock Tutorial – [Link]

Mini 7-Segment Clock V3

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Kevin Rye has written an article detailing his new Mini 7-segment clock v3:

I hope the LEGO minifig gives you a good sense of scale. This clock is pretty small. It’s amazing how small the Mini Clock has become after just 3 iterations. Just look at how small it is compared to version 1 and version 2.

Mini 7-Segment Clock V3 – [Link]

6 Digit LED Clock

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by sdgelectronics.co.uk:

I recently found six 2.3″ red 7 segment displays in my collection which I purchased from Rapid Electronics when they were clearing out non-RoHS stock. Since I have no clock at my work bench I decided to construct one from some prototyping pad board, a Microchip PIC18F26K20 microcontroller and a Dallas DS32KHZ temperature compensated 32.768kHz crystal.

6 Digit LED Clock – [Link]

Nixie Tube Clock

20150525_195643

by Peter @ petemills.blogspot.in:

Nixie tubes are cool. They have great aesthetic appeal with their difficult-to-photograph, warm orange glow, and dem curvy numerals. They add an organic je ne sais quoi to a hobby with ostensibly digital design cues. Further, they pose technical challenges in the way of producing and switching the ~175 V DC needed to light each tube element. And as far as I am aware, there are no new nixie tubes being produced; as such, procurement can be a challenge unto itself. My N.O.S. nixies came from Russia thru Ebay, and only 3 were duds. Incidentally the seller replaced those 3, FOC.

Nixie Tube Clock – [Link]

Large 7-Segment Clock

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by kevinrye.net:

I was extremely satisfied (and proud) of the way that the enclosure turned out for the rework of my 7490 Clock. The electronics on the other hand, is another story.

The innards of that clock were from a prototype I built in 2001. It was a proof of concept. It led to the design of what would become an extremely well-polished and accurate clock.

Since it was one of the first things I ever built, I decided to put it in an enclosure of its own and consider it too as a finished product.

The problem was that the prototype never ran properly. It worked, just not as well as it should. Needless to say, I tried to fix it in the way of an Arduino upgrade. On paper everything should run perfectly, but in the real world, it just doesn’t. The clock bounces all over the place. It’s more of a random number generator than a clock. I really thought that moving away from the 60Hz line signal as a timebase to a solid 1Hz signal from a DS3231 RTC would solve all my problems. At the end of the day, it boils down to the fact that it’s all soldered together on a DIY homebrew PCB. The holes that I drilled are too big for the pins; resulting in some pretty shoddy-looking soldering. It’s a noisy circuit, and I’m sure there’s some grounding issues in there too.

Large 7-Segment Clock – [Link]

Increasing Outputs from a Clock Source

ADF4351

In digital electronics, fan-out is defined as the number of gate inputs that the output of a single logic gate can feed. It is very important in digital systems for a single logic gate to drive other gates or devices. In this case, a buffer can be used between the logic gate and the devices it will drive. Clock buffer is also called as fan-out buffer. The IDT clock buffer clock divider and clock multiplexer portfolio includes devices with up to 27 outputs. Differential outputs such as LVPECL, LVDS, HCSL, CML, HSTL, as well as selectable outputs, are supported for output frequencies up to 3.2 GHz and single-ended LVCMOS outputs for frequencies up to 350MHz.

Modern digital systems often require many high quality clocks at logic levels that are different from the logic level of the clock source. Extra buffering may be required to guarantee accurate distribution to other circuit components without loss of integrity. Many systems require low jitter multiple system clocks for mixed signal processing and timing. The circuit shown in interfaces the ADF4351 integrated phase-locked loop (PLL) and voltage-controlled oscillator (VCO) to the ADCLK948, which provides up to eight low voltage differential signaling (LVDS) outputs from one differential output of the IDT 8SLVD1208-33. The IDT8SLVD1208-33I is characterized to operate from a 3.3V power supply. Guaranteed output-to-output and part-to-part skew characteristics make the IDT8SLVD1208-33I ideal for those clock distribution applications demanding well-defined performance and repeatability. Two selectable differential inputs and eight low skew outputs are available. The integrated bias voltage reference enables easy interfacing of single-ended signals to the device inputs. The device is optimized for low power consumption and low additive phase noise.

Fan-out buffers and clock dividers are general-purpose clock building block devices that can be used in any number of applications. They are ideal for clock and signal distribution in a large variety of systems, from personal computers to consumer electronics or industrial systems, as well as high-performance networking and communications systems.

Increasing Outputs from a Clock Source – [Link]