The Baofeng UV-5R uses a direct-conversion receiver rather than a conventional superheterodyne receiver with a separate IF stage. It uses an integrated RF transceiver IC from the RDA1846 family (some versions are marked AT1846S).
How the receiver works
The receiver uses quadrature direct conversion:
- The incoming RF signal passes through the RF front-end filtering and amplification.
- The signal is mixed down directly to baseband using quadrature mixing.
- Digital signal processing handles filtering and demodulation.
- The recovered audio is sent to the audio amplifier and speaker.
A technical examination of the RDA1846-based design describes it as a two-channel quadrature direct-conversion receiver. Unlike an older superheterodyne receiver, the UV-5R does not need a conventional chain of IF transformers and ceramic IF filters.
This helps make the radio:
- Small and inexpensive.
- Low in component count.
- Highly integrated.
- Relatively simple to manufacture.
One important point: Direct conversion doesn't necessarily mean a better receiver. The UV-5R has limitations in strong-signal handling, selectivity and susceptibility to interference. Having said that, I have several of these radios and they are excellent.