In this post, we are going to review and understand data collected from an Active Mixer tested at the bench. The mixer was designed for the only purpose of experimenting. Operating Principle The circuit is based around a common emitter BJT amplifier, DC bias is guaranteed by the 22k base
In this post we are going to take a look at a simple VCO I designed to accomplish a wide 2:1 tuning ratio, from 30 to 60MHz. Te design is based on a JFET Hartley topology with a BJT buffer. The resonant tank is made tunable by a pair
Hey guys, I'm creating this thread to archive what I discovered about the gyrator oscillator. The motivation came from a follower of mine. He had the idea to create a bode plotter. This kind of system demands a wide range VFO. My mind sparkled with the idea of
Sometimes when designing low frequency VCOs for HF and VHF bands we need high capacitance varicaps, to accomplish the desired frequency and sweep ratio. It is well-known that some rectifier and zener diodes act as general purpose varicaps, as the depletion capacitance is modulated by some applied DC voltage. To
There are many ways to accomplish frequency multiplication in analog and digital circuits. In modern systems, PLL and DPLLs are the most common, allowing multiple frequency outputs with arbitrarily phase relationship. Even so, a more fundamental approach, using harmonic generation, can be useful in a homebrew project, enabling fast prototyping,