In March, 2012, Abracon announced the production of ultra-low jitter, VCXO based frequency translators / jitter attenuators. This is supposed to resolve some problems that accompany classic PLL-based designs at an affordable price. Now, the ABFT frequency translators / jitter attenuators are available on the market and it’s time to have a closer look. The … [Read more…]
This article is going to take a closer look at the properties of a pseudo random bit sequence and a simple direct sequence spread spectrum signal both in the time- and frequency domain using the FFT capabilities of a Teledyne LeCroy WaveAce 1002. A while back, I posted an article about a Pseudorandom Number Generator … [Read more…]
Jackson Labs offers several different precision timing solutions. Among them are various GPS-disciplined oscillators. They sent me an evaluation board for one of their ultra small, low-cost GPSDO. So let’s check it out! The GPS-disciplined Oscillator (GPSDO) reviewed in this article is a state-of-the-art eval board from Jackson labs equipped with a high-performance GPS receiver, … [Read more…]
This is another piece of industry story time. This time it’s about Vislink MRC DAR Plus receivers and transmitters. It shows that even highly integrated devices in the USD 10K range can be repaired quickly and inexpensively. The MRC DAR Plus series transmitter / receiver are professional devices for studio-transmitter links (STL), transmitter-studio links (TSL), … [Read more…]
A while back, I was asked if I could repair a ODU for a BMS Truck-Coder II. Someone had managed to rip the N connector straight off the casing, including a bit of the microstrip line from the distributed element output filter. See what approach I took to fix the broken stripline. The BMS Truck-Coder … [Read more…]
There are tons of circuits for listening devices available on the internet. For the most part, they all have in common that they are virtually useless. This article shows how to build a reliable, small and inexpensive listening device using a PLL clock multiplier and a standard crystal. Most audio listening devices, also called spy … [Read more…]
FM demodulators have and always will be desired circuits. Many circuit designs use old and obsolete parts or appear to be too complicated for beginners. This design shows a very simple FM demodulator, a quadrature demodulator to be precise, for a 455 KHz IF using only a handful of parts and an NE602. The NE602 … [Read more…]
The core of any spread spectrum (and other cryptographic) system is a pseudo random number generator (PRNG). Pseudo random numbers play a big role in the world of electronics and cryptology. The quality of a spread spectrum link and its properties strongly depend on this device. For my Direct Sequence Spread Spectrum Experiments I needed … [Read more…]