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 […]
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Search Results for: RF xor
DSSS / BPSK Clock Recovery with the Abracon ABFT
Clock recovery in Spread Spectrum applications and BPSK modulated signals can be somewhat tricky. There are no commercial solutions available solely for this task either. Or are there? This article shows a great off-label use of the Abracon ABFT. Clock recovery in a Direct Sequence Spread Spectrum (DSSS) receiver can be quite a challenge. Because […]
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Review: Abracon ABFT Frequency Translators
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 […]
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Closer look at a Direct Sequence Spread Spectrum Signal
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 […]
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How it works: Quadrature detector
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 […]
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No Tune NE602 / NE612 FM Demodulator
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 […]
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Pseudorandom Number Generator (PRNG)
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 […]
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