Directly amplifying receiver

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Image:Directly amplifying receiver.jpg

Directly amplifying receiver. The first two transistors amplify the radio frequency. After the detection cascade (two diodes) the last transistor amplifies the sound frequency.

The Directly amplifying radio receiver is one example of the many different possible designs for a radio receiver. It contains a radio resonance filter, followed by a two-stage radio frequency (RF) amplifier, a diode detector, and a sound (audio) frequency amplifier.

This simple and stable design was usually preferred by radio amateurs in the early 1960's when they began experimenting with germanium transistors. However it is larger and consumes more power than the reflectional receiver of the same loudness and sensitivity, and is much less sensitive than the superheterodyne. It is also possible to find variants with only radio frequency amplifier stage (followed by the detector), or only the sound frequency amplifier with detection immediately after the resonance filter.