Advanced Receiver Architectures in Radio-Frequency Applications
The general principles of several types of receivers fall under the two main headings of TRF (tuned radiofrequency) receivers, where the received signal is processed at the incoming frequency right up to the detector stage, and the superhet (supersonic heterodyne) receiver, where the incoming signal is translated (sometimes after some amplification at the incoming frequency) to an intermediate frequency for further processing. There are however, a number of variants of each of these two main types. Regeneration (‘reaction’ or ‘tickling’) may be applied in a TRF receiver, to increase both its sensitivity and selectivity. This may be carried to the stage where the RF amplifier actually oscillates – either continuously, so that the receiver operates as a synchrodyne or homodyne, or intermittently, so that the receiver operates as a super-regenerative receiver, both of which have been described previously. The synchrodyne or homodyne may be considered alternatively as a superhet, where the IF (intermediate frequency) is 0 Hz. In this paper we present the new type of receiver architectures which work in radiofrequencies.
