Little spy bugs and tracking devices are generally very popular circuits in the electronics community. This is probably because the user gets to feel like James Bond and other special agents for a while. Let’s have a look at a simple tracking device. Spy bugs and tracking devices are not only very popular in the […]
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Search Results for: simple oscillator circuit
Low Noise Oscillator Design
The overall performance of any RF circuit in regards of it’s phase noise and spectral purity depends significantly on the frequency generating circuitry, commonly an oscillator. Low noise oscillators with high spectral purity are neither witchcraft nor black magic. Many people think the design of oscillators is black magic as such circuits usually either work […]
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Overtone Crystal Oscillator
Crystals with higher frequencies than about 30 MHz are almost exclusively overtone crystals. Such a crystal is intended to be used on an odd multiple of it’s fundamental frequency. Unfortunately, the crystal doesn’t want to resonate on it’s overtone frequency voluntarily, the oscillator circuit needs to force the correct overtone. For a little 2m band […]
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Simple oscillator as crystal tester
For homebrew crystal filters such as Cohn-Type or Ladder-Type filters it is often necessary to select crystals within 10 – 50 Hz of the target frequency. To make the selection process a little bit more pleasant, I designed this little test circuit. It is basically just a very simple oscillator utilizing a hand full of […]
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DIY Spark Gap Transmitter
This article plunges you into the mesmerrizing world of early radio technology through the assembly and analysis of a DIY spark gap transmitter. This project offers a practical insight into the fascinating dynamics of damped harmonic oscillators and explains charasteristics such the logarithmic decrement, decay rate, damping factor, q factor, and beyond. Prepare to spark […]
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LNB Modification for 10 GHz QO-100 Satellite Reception
This article shows how to modify an inexpensive LNB to accept an external LO-reference signal in order to be used as a K-band downconverter for QO-100 (Qatar Es’hail 2) amateur radio sattelite reception, radio astronomy or similar K-band experiments. This article is a shortened version of a scientific paper that I wrote as the lead […]
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ICS501 / ICS501 VHF Experiments
The ICS501 / ICS511 from Renesas are easy to use, fully integrated clock multipliers for output frequencies up to 200 MHz. What makes them particuarly interesting is the integrated crystal oscillator circuit and ability to produce some fractional multiples, such as 6.25 or 2.5. So let’s find out if they’re interesting for the hobbyist who […]
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Video Distribution Amplifier | 10 MHz Reference Distribution
Three Sigma VDA-100 Video Distribution Amplifiers (DA) have been sitting on my shelf for a while. The DAs have been waiting to be repurposed for something useful. When Jackson Labs sent me a custom variant of the FireFly-IIA GPS-Locked double ovenized 10 MHZ reference oscillator, I decided to repurpose one of the VDA-100 as a […]
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L-Network impedance matching
Impedance matching is an everyday problem for RF circuit designers. The L-Network is one of the easiest lossless ways of matching a low source impedance to a higher load impedance. This article shows how they work and how to design them. Matching a transistor amplifier’s low output impedance with the higher impedance of an antenna […]
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Review: Analog Devices ADF4351
Frequency generation is usually a very critical part in every RF design. The higher the target frequency, the higher complexity. Usually. With the ADF4351, Analog Devices offers an effort-saving component level solution for frequencies up to 4.4 GHz. The ADF4351 from Analog Devices (ADI) is a modern wideband PLL synthesizer with integrated low phase noise […]
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