Proper clock signal terminations app note from SiTime. Link here (PDF) Clock signals with fast edges see traces on Printed Circuit Boards (PCB) as transmission lines rather than simple wire connections. If the length of PCB trace exceeds certain limit it requires matching of the trace impedance to one or both of the source and […]
Tag Archives: oscillator
100 MHz third overtone crystal oscillator
100 MHz third overtone crystal oscillator @ DIYfan: Couple of years ago I purchased from a local store 100 MHz crystal resonator and tried several times to make a working schematic on breadboard using standard circuits I found on the internet. It never worked good enough, usually oscillating at 33.3 MHz instead of 100 MHz. […]
Building a chaotic oscillator from common components
cpldcpu writes: A chaotic oscillator is an electronic circuit that can exhibit “chaotic“, nonperiodic behavior. A commonly cited example is Chua’s circuit, but there are many others. I always regarded these as carefully designed, rather academic, examples. So I was a bit surprised to observe apparently chaotic behavior in a completely unrelated experiment. See the […]
App note: Oscillator design considerations
Interesting app note from Silicon Labs about oscillators used on their wireless SoC series 2 devices, oscillator basics included. Link here (PDF) An oscillator is an electronic circuit which generates a repetitive, or periodic, time-varying signal. In the context of Wireless SoC Series 2 devices, this oscillator signal is used to clock execution of instructions […]
App note: Driving multiple loads with 32 kHz Nano-Power MEMS oscillators
Accomodating multiple loads from a single oscillator output discussed in this app note from SiTime. Link here (PDF) Optimizing board space and managing power consumption of wearable devices is critical in sustaining competitiveness within this fast growing consumer segment. With less power consumed, battery life is extended or provides the option to reduce the battery […]
Open source Agilent 53132A 53131A OCXO ultra high stability oven upgrade
Gaurav Singh made an open source 53132A OCXO Ultra stability time base, that is available on github: While i was working with my own GPSDO project. i need to have a frequency counter with descent stability so purchased my self a Agilent 53132A which is a 12 digit frequency counter, big brother to 53131A 10 […]
Twin ‘T’ CW (Morse) Practice Oscillator
Steve Smith (G0TDJ) writes, “I successfully completed the Twin ‘T’ Oscillator, original by Mike Maynard – K4ICY. It’s a great circuit and sounds really good. Much better than a raspy 555 version. Mike has been kind enough to put a link to my project on his website.” More details at www.ProjectAVR.com.
App note: Microcontroller Clock – crystal, resonator, RC Oscillator, or silicon oscillator?
App note from Maxim Integrated on clock sources of microcontrollers and their strengths and weaknesses. Link here The majority of clock sources for microcontrollers can be grouped into two types: those based on mechanical resonant devices, such as crystals and ceramic resonators, and those based on electrical phase-shift circuits such as RC (resistor, capacitor) oscillators. […]
Fun with 1.1GHz Potato chips
Afroman writes, “I built a ring oscillator using a 1.125GHz 74 series logic inverter IC from Potato Semiconductor. It was fun.” Via Afrotechmods.
App note: Best design and layout practices for SiTime oscillators
SiTime’s app note about how to properly route an oscillator’s PCB traces. Link here Proper decoupling, bypassing, and power supply noise reduction is important in many applications to ensure optimal performance for oscillators. A common strategy is to place capacitors near high speed devices on a printed circuit board (PCB). These capacitors serve important functions: […]
Simple crystal tester
Dilshan Jayakody writes: This is simple Colpitts oscillator to test commonly available passive crystals which range between 2MHz to 27MHz. This unit must connect to an oscilloscope and/or frequency counter to get the frequency of the crystal. This circuit is design to work around 9V to 12V DC power source. Both 2SC930 transistors can replace […]
Building a better RTL-SDR TCXO
Craig posted an article describing how he built a 28.8MHz RTL-SDR TCXO, that is available on github: Here’s a scratch-built 28.8MHz TCXO capable of +-1ppm stability from 0C-55C; best of all, it’s not only easy to build, but is designed entirely from readily available and inexpensive components. For improved temperature stability, the main oscillator can […]
Audio oscillator with frequency counter
Xristost blogged about his DIY Audio oscillator with frequency counter project: After I finished the oscillator, I made some minor changes in the square signal part of the schematic. I connected five of the inverters in parallel with low value load resistors, thus reducing the influence of the parasitic capacitance of the PCB. The goal is […]
BFO for SSB reception
Dilshan Jayakody writes: This post is about beat frequency oscillator (BFO) module which is used to receive SSB and CW signals from ordinary shortwave receiver. The original circuit which is related to this post is obtained through the internet and we modify it to get more precise output with commonly available electronic components. (Unfortunately at the […]
Crystal oscillator frequency pulling
KF5OBS writes: This video briefly explains how to influence a crystal oscillator’s frequency by introducing reactive elements such as trim capacitors and inductors. This example uses a very simplistic Pierce oscillator and a crystal ins series resonance.
DS1077 + Arduino
Wardy has documented his DS1077 configurable oscillator with the Arduino: I’ve finally had a chance to get around to playing with the DS1077 configurable oscillator! The circuit to get it working is very simple, just hook up the Ardiono as the I2C master, I used a 10K pullup resistor on both the SCL and SDA lines. […]
ATMega328 RC vs quartz oscillator comparison
Kenneth compares the RC oscillator found on the ATMeg328 against an external quartz crystal. As expected there is a huge difference in precision and stability between the two. This really demonstrates how both oscillators, but particularly the internal one, are very sensitive to temperature changes around the microcontroller. This is why my counter’s oscillator is […]
7400 competition entry: FM modulation and demodulation system
Alifred and his friend entered a FM modulation, demodulation and transmission system into the Open 7400 Logic Competition. An input waveform enters the Voltage Controlled Oscillator (VCO), resulting in a FM modulated waveform. This is then sent to an IR LED (through a buffering MOSFET) and is received by a photo-transistor at the other end. […]
Constant temperature crystal oscillator
Crystal oscillators generate pretty accurate frequencies, but the output varies a bit depending on the operating temperature. The crystal oven heats a crystal to a constant temperature to get the most accurate and consistent frequency possible. Via Hack a Day.