Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently. The major concern is the low input impedance of the detector-amplifier bipolar stage. Nevertheless, it can be easily compensated with positive feedback or regeneration. A sufficient amount of regeneration can make tuning astonishingly sharp. Another concern is the [...]
This idea presents a simple circuit for a superhet radio receiver that can be built up in sections, with each section tested before assembly. The receiver circuitry as presented here can be built for less than $50.
Don’t be misled—even though the set has some pretty obvious limitations as presented, it’s still capable of worldwide reception [...]
Cell phones aren’t the only devices to benefit from ever- smaller and more highly integrated communications-IC technology. The simple, three-IC superheterodyne radio in Figure 1 can receive stations in the 4.5- to 10-MHz range from around the world with only a 10-ft antenna. A superheterodyne radio works by mixing the incoming RF signal with a [...]
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