The most common way to ‘kill’ a Atmel AVR microcontroller is by programming fuse bits wrong. Sooner or later every Atmel AVR enthusiast will stumble across a fuse-bit related problem. The most common mistake, a wrong clock source selection through the CKSEL fuse-bit, can be fixed easily. The fuse-bits CKSEL0 through CKSEL3 let the microcontroller … [Read more…]
A low-noise block downconverter (LNB) is a key element in a satellite receiver system and is responsible for converting the relatively high frequency of the received signal into the more convenient L-Band. But how do they work and what do they look like on the inside? Let’s have a look! From a theoretical standpoint, a … [Read more…]
More and more computers (especially laptops) aren’t equipped with serial and / or parallel ports anymore. Therefore, more and more programming interfaces utilize USB instead. However, some people are extremely attached to their older serial / parallel programmers and often oversee how a USB based device can simplify their life a lot. Atmels’s AVRISP mkII … [Read more…]
An Oven Controlled Crystal Oscillator (OCXO) is used wherever one needs a highly accurate and precise frequency reference. Abracon manufactures a series of affordable off-the-shelf OCXOs, which are due to their low price and outstanding performance particularly suitable for homebrew designs. Abracon’s AOCJY1 series offers various through-hole OCXOs with several possible frequencies between 10 MHz … [Read more…]
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 … [Read more…]
Many integrated FM quadrature demodulation circuits, such as the MC3361 or MC3362, have a defined LC tank circuit that creates a specific phase shift of 90 degrees at the center frequency of the demodulator. Let’s take a closer in depth look at how they work. A quadrature demodulator for FM signals consists out of two … [Read more…]
A phase detector generates a voltage proportional to the difference in phase between two signals. They are used in Phase-Locked-Loop (PLL) designs and PM / FM demodulator circuits. But how do they work? I promised in a previous blog article titled ‘No Tune NE602 / NE612 FM Demodulator’ that I would explain how a quadrature … [Read more…]
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 … [Read more…]