The problem with TRF architectures was that multiple stages of tuned filters were expensive. Later models mechanically coupled the variable capacitors of each filter section together so that the user would only need to turn one knob to tune in a station.īlock diagram, schematic, and, photos of a typical TRF radio. To tune in a station you would simply tune each of the filters to the desired frequency. The output of the last tunable filter was fed into an envelope detector (a diode) where the demodulated audio was amplified and played out of a loudspeaker. The signal chain consisted of an antenna to collect the radio signal which was fed into four stages of filtering interspersed with three stages of amplification. The earliest radio architecture was known as tuned radio frequency (TRF), which became widely adopted in the mid to late 1920s for use in consumer receivers. My favorite way of abstracting radio architecture is to consider everything at the block diagram level: filters, amplifiers, multipliers (or mixers as we call them), and assume all blocks are impedance matched. To understand how an SSB transceiver works we must first review the basic architectures of radio receivers. I am one of those die-hards, and in this post I will show you how to get started. In reality, due to the proliferation of low-cost amateur equipment, there only exists a very small group of die-hards who actually design, build from scratch, and operate their own SSB transceivers. The most complicated part of this communication system is the single-sideband (SSB) high frequency (HF) transceiver. Amateur radio is the only hobby that offers its licensed operators the chance to legally design, build, and operate high power radio transceivers connected to unlimited antenna arrays for the purpose of communicating anywhere in the world.
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